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At least 181 records · Page 10Linked to original sources

PubMed2006

Controlled trial of immediate endoluminal closure of colon perforations in a porcine model by use of a novel clip device (with videos).

BACKGROUND: Although endoluminal closure of a small perforation of the colon is technically feasible, the outcome of such a closure is unclear. OBJECTIVE: Our purpose was to evaluate the feasibility and the outcome of endoluminal closure of a small perforation of the colon with a novel clip device, the InScope MultiClip Applier (IMCA), and to assess the number of clips required for successful closure. DESIGN: Prospective controlled study. SETTING: University hospital. ANIMALS: 17 pigs. INTERVENTIONS: A 2-cm full-thickness colon perforation was randomized to 3 groups: control, no closure (n = 4), 2-clip closure (n = 7), and 4-clip closure (n = 6). MAIN OUTCOME MEASUREMENTS: (1) Technical feasibility of closure, (2) closure time, (3) clinical monitoring for 2 weeks, (4) necropsy (day 14), and (5) healing by a dye leak test and histologic examination. RESULTS: Endoscopic closure of the colon perforation was technically successful in 12 of 13 animals. A wide gaping hole prevented satisfactory closure in 1 animal. The median time for closure with 2 and 4 clips was 2 and 3 minutes, respectively. Clip closure of perforation prevented clinical sepsis (P = .008) and diminished the risk for fibrinous peritonitis (P = .02 for a single test of hypothesis; however, correction for the multiple testing of data removes this significance) and adhesion formation (P = .008) compared with controls, without any leakage. The outcomes of 2- and 4-clip closure were similar. CONCLUSIONS: Endoluminal closure of a 2-cm colon perforation with clips is successful in preventing peritonitis and adhesions and it can be accomplished quickly with this novel device. Clip closure at 1-cm intervals is sufficient for successful closure of a 2-cm colon perforation.

Animals↗

PubMed2005

Definition of postlumpectomy tumor bed for radiotherapy boost field planning: CT versus surgical clips.

PURPOSE: To compare the location and extent of the tumor bed as defined by surgical clips and computed tomography (CT) scans, after lumpectomy, for electron boost planning as part of breast radiotherapy. METHODS AND MATERIALS: Planning CT images of 31 operated breasts in 30 patients who underwent lumpectomy were reviewed. One or more clips were placed in the lumpectomy cavity. Serial CT images were used to measure the depth and transverse and longitudinal dimensions. The area and geometric center of the tumor bed were defined by the clips and CT. RESULTS: The CT and clip measurements were identical for the maximal tumor depth in 27 of 30 patients. The CT bed extended beyond the clips by 0-7 mm medially in the transverse/longitudinal extent (multiclip patients). The median distance between the geometric centers in the coronal plane for the tumor bed center was larger for patients with single clips than for those with multiple clips (p < 0.025). Tumor bed areas in the coronal plane defined by both methods correlated strongly. However, the CT-defined area was larger by 13.9 mm2. The CT bed was more readily visible in patients with a shorter interval between surgery and radiotherapy. CONCLUSION: The maximal depth of the tumor bed was similar using the two methods. The extent and centers of the clip-and CT-determined beds differed significantly. This may indicate an underestimation of the tumor bed as defined by clips only and justifies integration of CT information in boost field planning.

Adult↗

PubMed1999

Anastomotic tissue response associated with expanded polytetrafluoroethylene access grafts constructed by using nonpenetrating clips.

PURPOSE: The gross, light microscopic, and scanning microscopic appearance of arterial and venous anastomoses in expanded polytetrafluoroethylene (ePTFE) access grafts constructed with nonpenetrating clips were compared with that of those constructed with polypropylene suture. We hypothesized that clip-constructed anastomoses would provide controlled approximation of native vessel intimal and medial components with the ePTFE grafts. We further hypothesized that anastomotic healing with clips would involve primarily an intimal cellular response, as compared with suture-constructed anastomoses in which cells within the media and adventitia walls participate. METHODS: Femoral artery to femoral vein arteriovenous (AV) grafts were constructed in five dogs using 4-mm internal diameter ePTFE graft material. Each animal received one AV graft with anastomoses constructed by using polypropylene sutures in one leg and one AV graft with anastomoses constructed with Vascular Closure System clips in the contralateral leg. Animals were given aspirin for the duration of the study, and grafts were explanted at 5 weeks. At the time of explantation, graft segments were grossly evaluated and then underwent light and scanning electron microscopic analysis. RESULTS: At the time of explantation, all access grafts were patent. Joining the ePTFE grafts to the native vessels with clips resulted in minimal vessel wall damage. The lumenal contours of the discontinuous approximation were smooth and without gross endothelial disruption. These observations are in contrast to the lumenal compromise and endothelial disturbance associated with the sutured anastomoses. Furthermore, hemostasis was achieved immediately in the clipped grafts, decreasing the incidence of perianastomic hematoma. Finally, cellular reconstitution occurred at the anastomotic cleft in both the sutured and the clipped junctions. The neointima exhibited an endothelial cell lining on the lumenal surface and the presence of alpha-smooth muscle cell actin positive cells within the subendothelial layer. CONCLUSION: Vascular Closure System clips are a viable alternative to suture for the approximation of ePTFE AV access grafts to native blood vessels. The use of the clips resulted in a more streamlined anastomosis, with decreased vessel wall damage, immediate hemostasis, and a trend toward shorter procedure times.

Animals↗

PubMed2001

[Breast-conserving surgery and irradiation for early breast cancer: value of surgical clips in the surgical cavity].

PURPOSE: To evaluate, qualitatively and quantitatively, the role of surgical clips in planning the tumor bed electron or brachytherapy boost in patients undergoing breast-conserving surgery and radiotherapy. PATIENTS AND METHODS: In 60 patients with breast cancer stage I or II, the excision cavity boundaries were marked by clips at surgery. Patients received a boost with brachytherapy (n = 51) or electron beam (n = 9) after whole breast irradiation. The boost target volume was first planned using clinical, mammography and operative information and its accuracy evaluated by screening the surgical clips and, if necessary, adjusting the field to encompass all clips and to include the scar. Dosimetry was retrospectively performed for each brachytherapy patient and for each surgical clip. RESULTS: It was necessary to modify the target volume field in 11 cases (18%). The average dose received by the surgical clips was 116.1% of the dose delivered to the reference isodose (median: 101.75%, range: 16-457%). However, dose heterogeneity was important in the same patient and between patients. CONCLUSION: Delineation of the boost target volume with surgical clips is more accurate than with clinical landmarks alone but this technique does not allow measurements of the clip-chest wall and clip-skin distances. Virtual simulation with CT-scan cuts is recommended for optimising boost planning.

Brachytherapy↗

PubMed2003

Intraaneurysmal flow changes affected by clip location and occlusion magnitude in a lateral aneurysm model.

In order to study the flow dynamic changes inside an aneurysm sac due to the partial occlusion of the aneurysm neck, velocity fields were measured using a particle image velocitimeter (PIV) in in vitro aneurysm models under the physiological flow waveform. Lateral aneurysm models arising from the curved parent vessel with different occlusion ratios and sites-e.g. no clip, 50% proximal and distal clip, and 75% proximal and distal clip-were tested. Reduced inflow and intraaneurysmal velocities may provide a better hemodynamic environment for aneurysm embolization. Comparing inflow rates and averaged intraaneurysmal velocities in the proximal and the distal clip model, they were lower in the distal clip model in cases of 50% neck occlusion, but they were lower in the proximal clip model in cases of 75% occlusion. These results suggest that clipping sites for reduced inflow and intraaneurysmal flow velocities may differ for different residual neck sizes. Less effective inflow blocking in the 75% distally clipped model may be due to the curvature of the parent artery. Therefore, not only the residual neck size and clipping site but the geometry of parent vessel significantly affect the flow fields inside the aneurysm, and subsequently the success of the aneurysm treatment.

Blood Flow Velocity↗

PubMed2005

CLIP-170 facilitates the formation of kinetochore-microtubule attachments.

CLIP-170 is a microtubule 'plus end tracking' protein involved in several microtubule-dependent processes in interphase. At the onset of mitosis, CLIP-170 localizes to kinetochores, but at metaphase, it is no longer detectable at kinetochores. Although RNA interference (RNAi) experiments have suggested an essential role for CLIP-170 during mitosis, the molecular function of CLIP-170 in mitosis has not yet been revealed. Here, we used a combination of high-resolution microscopy and RNAi-mediated depletion to study the function of CLIP-170 in mitosis. We found that CLIP-170 dynamically localizes to the outer most part of unattached kinetochores and to the ends of growing microtubules. In addition, we provide evidence that a pool of CLIP-170 is transported along kinetochore-microtubules by the dynein/dynactin complex. Interference with CLIP-170 expression results in defective chromosome congression and diminished kinetochore-microtubule attachments, but does not detectibly affect microtubule dynamics or kinetochore-microtubule stability. Taken together, our results indicate that CLIP-170 facilitates the formation of kinetochore-microtubule attachments, possibly through direct capture of microtubules at the kinetochore.

Cells, Cultured↗

PubMed2003

Trans-catheter arterial chemoembolisation for hepatocellular carcinoma in patients with viral cirrhosis: role of combined staging systems, Cancer Liver Italian Program (CLIP) and Model for End-stage Liver Disease (MELD), in predicting outcome after treatment.

BACKGROUND: Trans-catheter arterial chemoembolisation (TACE) is the most common palliative treatment for hepatocellular carcinoma (HCC). The therapeutic options depend both on the characteristics of the tumour and on functional staging of the cirrhosis. AIM: To evaluate the effects of TACE on the survival of cirrhotic patients with HCC according to different staging systems [Okuda score, Cancer Liver Italian Program (CLIP) score, Model for End-stage Liver Disease (MELD) score] and in relation to the side-effects of TACE. METHODS: Fifty cirrhotic patients, 36 CTP class A and 14 class B, underwent 106 TACE treatments with mitoxantrone. Survival at 12, 24, and 36 months was evaluated. RESULTS: MELD at 12 months and CLIP at 24 months were identified as significant variables associated with survival. Combined cut-offs of CLIP and of MELD identified four subgroups of patients with different survivals, at 12, 24 and 36 months, respectively: CLIP >or= 2 and MELD >or= 10 (63%, 20% and 0%), CLIP < 2 and MELD >or= 10 (73%, 40% and 22%), CLIP >or= 2 and MELD < 10 (73%, 40% and 22%) and CLIP < 2 and MELD < 10 (100%, 63% and 50%). Post-TACE side-effects proved to have no influence on survival. CONCLUSION: In patients with poor probability of survival (CLIP >or= 2 and MELD >or= 10), TACE must be planned with a great deal of caution, while in patients with possibly good outcomes (CLIP < 2 and MELD < 10), more 'aggressive' therapy should be taken into consideration.

Adult↗

PubMed1995

Binding of major histocompatibility complex class II to the invariant chain-derived peptide, CLIP, is regulated by allelic polymorphism in class II.

Major histocompatibility complex class II-associated invariant chain (Ii) provides several important functions that regulate class II expression and function. One of these is the ability to inhibit class II peptide loading early in biosynthesis. This allows for efficient class II folding and egress from the endoplasmic reticulum, and protects the class II peptide binding site from loading with peptides before entry into endosomal compartments. The ability of Ii to interact with class II and interfere with peptide loading has been mapped to Ii exon 3, which encodes amino acids 82-107. This same region of Ii has been described as a nested set of class II-associated Ii peptides (CLIPs) that are transiently associated with class II in normal cells and accumulate in human histocompatibility leukocyte antigen-DM-negative cell lines. Currently it is not clear how CLIP and the CLIP region of Ii blocks peptide binding. CLIP may bind directly to the class II peptide binding site, or may bind elsewhere on class II and modulate class II peptide binding allosterically. In this report, we show that CLIP can interact with many different murine and human class II molecules, but that the affinity of this interaction is controlled by polymorphic residues in the class II chains. Likewise, structural changes in CLIP also modulate class II binding in an allele-dependent manner. Finally, the specificity and kinetics of CLIP binding to class II molecule is similar to antigenic peptide binding to class II. These data indicate that CLIP binds to class II in an analogous fashion as conventional antigenic peptides, suggesting that the CLIP segment of Ii may actually occupy the class II peptide binding site.

Alleles↗

PubMed2004

Routine vascular control using the Hem-o-lok clip in laparoscopic nephrectomy: animal study and clinical application.

BACKGROUND AND PURPOSE: During laparoscopic nephrectomy (LPN), a stapling device is often used for vascular control, especially of the renal vein. Herein, we report our experience using a polymer clip (Hem-o-lok) for routine control of the vessels during LPN in the animal and clinical setting. PATIENTS AND METHODS: Fifty ablative and fifteen live-donor nephrectomies were performed in domestic pigs. Hem-o-lok clips (10 mm; Weck Closure System, Research Triangle Park, NC) were routinely used for vascular control. In addition, from January 2001 to July 2002, 46 patients underwent hand-assisted laparoscopic (HAL) (N=40) or laparoscopic (N=6) nephrectomy for renal disease or donor nephrectomy. Venous control was achieved solely by the Hem-o-lok clips where at least two clips were applied on the patient side. Arterial control was obtained by the Hem-o-lok clips either alone or in combination with the metal clips. The technical difficulty in obtaining vascular control, transfusion requirement, and clinical outcome were evaluated. RESULTS: In the animal study (total 65 nephrectomies), individual vascular control was obtained by the Hem-o-lok clip in all cases except two, where vascular injury during dissection necessitated endoscopic stapling of renal hilum or open conversion. The warm ischemic time for animal donor kidney harvest was uniformly <2 minutes. In the clinical study, arterial control was obtained mostly by a combination of Hem-o-lok and metal clips. Venous control using the Hem-o-lok was successful in all 46 cases without any slipping of clips or uncontrolled bleeding. The mean operating time was 148 minutes. No open conversion was required. The transfusion rate was 6.5% (N=3), with none of the transfusions being related to inadequacy of vascular control using the Hem-o-lok. Major complications included deep vein thrombosis and postoperative retroperitoneal hemorrhage (same patient) and acute respiratory distress syndrome (N = 1). The mean postoperative stay was 5.2 days (range 1-20 days). CONCLUSION: The Hem-o-lok is a reliable and economical device for vascular control in laparoscopic renal surgery.

Animals↗

PubMed2006

Hem-o-lok clips for vascular control during laparoscopic ablative nephrectomy: a single-center experience.

BACKGROUND AND PURPOSE: Vascular control is an important step in laparoscopic nephrectomy. The various options are titanium clips, Hem-o-lok clips (Weck Closure Systems, Research Triangle Park, NC), T-knot, and stapling devices. We report our experience with the use of Hem-o-lok clips. PATIENTS AND METHODS: From January 2001 to June 2004, 246 laparoscopic ablative nephrectomies (178 simple; 68 radical) were performed at our institute for benign and malignant conditions. All patients (mean age 46.76+/-26.31 years) were evaluated by detailed history and physical examination and laboratory investigations and underwent standard transperitoneal (N=204) or retroperitoneal (N=42) nephrectomy. Venous and arterial control was obtained using Hem-o-lock clips. In cases where the clips could not be applied directly on the renal vein, various maneuvers were employed to secure the occlusion. The features compared were the number of clips used, safety, cost, and requirement for blood transfusion. RESULTS: Conversion to an open procedure was required in 36 patients (28 in the transperitoneal group and 8 in the retroperitoneal group). The mean operative time was 280+/-35 minutes and 235+/-44 minutes in the retroperitoneal and transperitoneal groups, respectively. In all cases, arterial and venous control was achieved by application of two Hem-o-lok clips on the patient side. Blood transfusion was required by 7.2% of the patients (right-side nephrectomy 4.6%; left side nephrectomy 2.6%), but none was attributable to clip-related complication. The mean postoperative hospital stay was 3.4 days. CONCLUSION: Hem-o-lok clips are a reliable and cost-effective means of achieving vascular control during laparoscopic nephrectomy.

Adult↗

PubMed1997

A continuous central motif of invariant chain peptides, CLIP, is essential for binding to various I-A MHC class II molecules.

Invariant chain (li) associates with MHC class II molecules and performs a number of crucial functions in antigen presentation. A nested set of class II-associated li peptides (CLIP) has been isolated, comprising the li sequence between residues 82 and 107. Recently, X-ray crystallographic analysis has revealed that residues 87-101 occupy the HLA-DR3 peptide-binding groove. Based on our previous results, Lee and McConnell have also proposed a model for the binding of CLIP to various mouse I-A molecules in the binding groove. CLIP sequences are able to bind many MHC class II molecules but the molecular basis of this promiscuity has not yet been resolved. We have shown recently that CLIP binding to I-A class II molecules is generally tolerant to side chain substitutions, suggesting that the backbone structure of CLIP may provide the features critical for its interaction with class II. In pursuit of this, backbone stereochemical disruptions by serial D-alanine substitutions in CLIP86-104 have been used in competitive binding assays to I-A class II molecules. These studies have revealed that the phylogenetically conserved central continuous region, CLIP91-99, is intolerant to such configurational substitutions. Experiments with truncated and frame-shift analogues of CLIP showed that for effective binding to class II, the sequence element CLIP90-100 must be incorporated into a peptide of 13 or more residues including at least three residues N-terminal to this motif. Additionally, it appears that different I-A molecules accommodate CLIP in different binding frames. These investigations of the relationship between the structure and binding of CLIP analogues lead us to propose that there is a general backbone motif of a periodic nature within the CLIP sequence that minimizes deleterious contacts and allows promiscuous binding to class II molecules.

Amino Acid Sequence↗

PubMed2000

Scaled clips for aneurysm surgery: technical note.

OBJECTIVE: The tips of clip blades are often invisible during operations on large, deep, or posteriorly projecting aneurysms. To overcome this problem, we sought to develop a series of scaled clips. METHODS: We made scaled clips modified from Yaşargil titanium clips. The blades of the new clips are scaled every 5 mm from the tips with alternating colors. We have added six new types of straight scaled clips. RESULTS: To date, we have performed approximately 40 aneurysm clippings using the new scaled clips and have confirmed their usefulness. CONCLUSION: Scaling on the blades helps confirm accurate placement of a clip, even during operations for large, deep, or posteriorly projecting aneurysms, in which blade tips are often invisible.

Equipment Design↗

PubMed2005

First experience with a new stapes clip piston in stapedotomy.

OBJECTIVE: Hearing results after 23 implantations of a newly designed titanium-clip stapes piston prosthesis (the àWengen Clip Piston prosthesis) in patients with otosclerosis were evaluated. This new type of stapes piston was designed to avoid the crimping onto the incus in stapedotomy. This one clip fits all designs and enables solid fixation by clicking the prosthesis onto the long process of the incus without crimping. STUDY DESIGN: A retrospective pilot study was carried out by microcomputer of the preoperative and postoperative audiological results of patients in whom the titanium-clip stapes piston prosthesis was implanted. SETTING: Ear, nose and throat department of Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. PATIENTS: 23 Patients underwent a stapedotomy for hearing improvement suffering from otosclerosis. implantations of a newly designed titanium-clip stapes piston prosthesis (the àWengen Clip Piston prosthesis) in patients with otosclerosis were evaluated. INTERVENTION(S): The stapedotomy was performed with the àWengen Clip Piston prosthesis. MAIN OUTCOME MEASURE(S): Pre and postoperative audiograms were used to evaluate the hearing gain improvement with the new stapes piston. Especially we looked at the airbone gap closure and the sensorineural hearing after the surgical procedure and compared these with the ones before surgery. RESULTS: The hearing results showed a closure of the pure-tone average air-bone gap to within 10 dB in 56.6% of cases (10 of 23 implantations) and to within 20 dB in 100% (23 of 23 implantations). A residual air-bone gap of greater than 20 dB was seen in the present pilot study. Postoperative overclosure of bone-conduction thresholds was discovered only for the frequency of 2 kHz. Sensorineural hearing loss greater than 10% did not occur, and there was no decline in the speech discrimination. CONCLUSIONS: The use of a newly designed titanium-clip stapes piston prosthesis with a diameter of 0.4 mm gives good results in cases of stapedotomy for otosclerosis. The titanium-clip design is a new development in the evolution of stapes piston prostheses. Surgical introduction, placement, and fixation are not always easy, depending on the anatomy of the middle ear and the thickness of the fixation area on the long process of the incus.

Audiometry↗

PubMedDate not supplied

Recognizing pitfalls in early and late migration of clip markers after imaging-guided directional vacuum-assisted biopsy.

Directional vacuum-assisted biopsy has become an irreplaceable tool in the management of suspicious mammographic lesions. Often, the entire lesion is removed and clips are used to localize the biopsy site. Postbiopsy mammograms are used to determine the adequacy of clip placement and the location of the clip. Clip displacement from the site of deployment is not an uncommon finding. Clips may migrate within the same quadrant where the lesion was located or to another quadrant of the breast. Clip migration may occur immediately after biopsy or may be seen on later follow-up mammograms. Clip migration can affect interpretation of mammographic findings and localization for future surgery. It should not be assumed that the clip is correctly located at the biopsy site on subsequent mammograms. It is essential to recognize the relationship of the clip to the targeted lesion to ensure accurate localization of lesions that require surgical excision.

Biopsy, Needle↗

PubMed1986

Autoregulation of renal blood flow in two-kidney, one-clip hypertensive rats.

Renal blood flow (RBF) autoregulation was examined in the clipped and nonclipped kidneys in two groups of two-kidney, one-clip (2K-1C) hypertensive rats 10 wk after clipping. The arterial pressure distal to the clip and the renin secretion rate (RSR) were also examined. The blood pressure (BP) was 149 +/- 4 and 162 +/- 6 mmHg in the two hypertensive groups vs. 114 +/- 3 mmHg in the controls (P less than 0.02). The RBF (in ml X min-1 X kidney-1) was 4.27 +/- 0.41 in the nonclipped and 2.18 +/- 0.23 in the clipped kidneys (P less than 0.001). The pressure distal to the clip was 104 +/- 7 mmHg. The renal vascular resistance (RVR) (in mmHg X ml-1 X min-1 X g-1) was 25.0 +/- 1.4 in the control kidneys vs. 58.4 +/- 4.5 in the nonclipped (P less than 0.001) and 39.9 +/- 6.6 in the clipped kidneys (P less than 0.01). The RBF autoregulation was well preserved in the nonclipped kidneys but reset to a higher lower pressure limit of autoregulation of 106 +/- 4 mmHg, which was significantly higher than in the normotensive controls (84 +/- 6 mmHg) (P less than 0.01). In the clipped kidneys there was complete loss of RBF autoregulation. RSR decreased with reduction of the perfusion pressure in the clipped kidneys. The increased RVR might have been due to a combination of structural and functional changes in both kidneys.

Animals↗

PubMed2001

Risk of aneurysm recurrence in patients with clipped cerebral aneurysms: results of long-term follow-up angiography.

BACKGROUND AND PURPOSE: With many patients living long after microsurgical aneurysm clipping for subarachnoid hemorrhage (SAH) and with the evolution of intravascular procedures as less invasive alternatives, knowledge of the long-term results of clipping is becoming important. METHODS: Of 412 patients who underwent clipping of ruptured or unruptured cerebral aneurysms at our institution between 1976 and 1994 and who survived >3 years after surgery, 225 patients who were in good general condition and younger than 80 years were offered follow-up angiography to detect newly formed aneurysms. Of the 225, 80 patients (35.6%) agreed to undergo angiography. In addition, 32 patients underwent angiography for new medical indications other than SAH. Therefore, 112 patients underwent angiography, representing a total of 140 clipped aneurysms. RESULTS: The mean interval from surgery was 9.3 years for all patients and 9.0 years for the clipped aneurysms (range 3 to 21 years). Four aneurysm regrowths were detected of the 140 (2.9%) clipped aneurysms, representing 3 of 125 completely clipped aneurysms, 1 of 14 incompletely clipped aneurysms, and 0 of 1 aneurysm not studied with postoperative angiography. De novo aneurysms were detected in 9 of 112 (8.0%) patients. The annual rate of de novo aneurysm formation was 0.89%. CONCLUSIONS: This study shows that the annual rate of de novo aneurysm formation is relatively high (0.89%) and that the cumulative risk becomes significant after 9 years. In consideration of the fatality rate of SAH, follow-up angiography may be indicated for patients with clipped aneurysms 9 to 10 years after surgery.

Angiography, Digital Subtraction↗

PubMed1986

Effect of ketanserin on pressor response to vasoactive substances in early phase of one-kidney, one clip renal artery stenosis in rats and rabbits.

The effect of ketanserin (KET), a specific 5-hydroxytryptamine2 (5-HT2) receptor blockade, on pressor response to vasoactive substances was examined in rats with one-kidney, one clip renal artery stenosis of 2 days' duration (2-day clipped rat) and in rabbits with renal artery stenosis of 3 days' duration (3-day clipped rabbits). The 2-day clipped rats showed hyperresponsiveness to norepinephrine (NE), arginine vasopressin (AVP) and 5-HT. All hyperresponsiveness were attenuated by a subdepressor dose of KET. The infusion of KET, 10 micrograms/kg/min for 30 minutes, decreased mean arterial pressure of the 3-day clipped rabbits; the dose did not alter blood pressure of the normal controls. Exaggerated pressor response to NE was observed in the 3-day clipped rabbits and was abolished by a subdepressor dose of KET, 2.5 micrograms/kg/min. These results suggest that 5-HT may be involved in the enhanced pressor response to vasoconstrictor substances in the 2-day clipped rats and 3-day clipped rabbits, and that it may also play an important role in maintaining blood pressure in the 3-day clipped rabbits.

Animals↗

PubMed2005

Effects of temporary clips on somatosensory evoked potentials in aneurysm surgery.

INTRODUCTION: Changes in somatosensory evoked potentials (SEPs) were used to identify cerebral ischemia and to predict neurological outcome during the application of temporary clips in aneurysm surgery. METHODS: SEPs were recorded intra-operatively in 76 patients with 79 aneurysms (8 in the posterior fossa). Twenty aneurysms ruptured during surgery, and 37 temporary clips were applied over an average of 8.1 minutes (range: 2-25 minutes). RESULTS: Of 17 cases with complete loss of potential, 14 were associated with temporary clips. Two losses were persistent with postoperative neurological deficit after 10 minutes of clipping. Six showed incomplete recovery after a mean loss of 19.2 minutes following clipping of 9.3 minutes, resulting in a new deficit in four patients. Despite complete recovery of potential in six patients after a 1 loss over 18.8 minutes following clipping of 10.7 minutes, four patients developed neurological deficits. The sensitivity of SEPs in determining permanent neurological deficits was 57%, and the was specificity 88%. The duration of temporary clipping was significantly shorter in patients without resulting new neurological deficit (Mann-Whitney Test; p < 0.01). The risk of a new deficit was 30.7% in cases where less than 8 minutes of clipping was performed, and the risk was 80.9% when clipping exceeded 8 minutes. The extent of recovery of potentials and the duration of SEP changes was strongly associated with the postoperative deficits (Kolmogorov-Smirnov Test, p = 0.009; p = 0.001, Mann-Whitney Test). Pathological p(ti)O2 measurements were obtained in 6 of 12 patients. In four patients, temporary occlusion was followed by a parallel alteration of SEPs and p(ti)O2 below 10 mmHg. CONCLUSION: There is no genuinely safe permissible occlusion time. Despite complete recovery of SEPs after a loss of potential, the patient may develop new deficits.

Adult↗