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At least 1,441 records · Page 80Linked to original sources
PubMed1999

Altered expression of Gi-protein and adenylyl cyclase activity in hearts from one kidney one clip hypertensive rats: effect of captopril.

OBJECTIVE: To investigate whether one kidney one clip (1K-1C) hypertensive rats associated with high levels of angiotensin II (Ang II) exhibit enhanced expression and functions of G proteins in the heart and whether the enhanced expression can be attributed to Ang II. METHODS: The levels of G protein and G protein mRNA in hearts from 1K-1C hypertensive rats were determined by immunoblotting and Northern blotting techniques using specific antibodies and cDNA probes, respectively, for different isoforms of G proteins. Adenylyl cyclase activity, stimulated or inhibited by agonists, was determined to examine the function of G proteins. RESULTS: The levels of Gialpha-2 and Gialpha-3 proteins and mRNA were significantly increased in hearts from 1K-1C hypertensive rats compared with control rats, whereas the levels of Gsalpha were unchanged. Guanosine 5'-[3'-thio] triphosphate (GTPgammaS), isoproterenol, glucagon, sodium fluoride (NaF) and forskolin (FSK) stimulated adenylyl cyclase activity in hearts from control and hypertensive rats to varying degrees; however, the stimulations were significantly less in hypertensive rats compared with control rats. On the other hand, the inhibitory effect of low concentrations of GTPgammaS on FSK-stimulated adenylyl cyclase activity (an index of Gi function) was significantly enhanced in hearts from 1K-1C hypertensive rats, whereas the inhibitory effect of C-ANF4-23 on adenylyl cyclase was increased and that of Ang II was decreased in hearts from 1K-1C hypertensive rats. Captopril, an angiotensin-converting enzyme inhibitor, restored the augmented levels of Gi proteins and also the altered stimulation and inhibition of adenylyl cyclase by GTPgammaS, stimulatory and inhibitory hormones, respectively, in hearts from hypertensive rats. CONCLUSION: These data suggest that 1K-1C hypertensive rats exhibit enhanced expression of Gialpha proteins and associated functions that may be attributable to the enhanced levels of Ang II in this model of hypertension.

Adenylyl Cyclases↗
PubMed2004

Cardiovascular hypertrophy in one-kidney, one-clip renal hypertension is resistant to heparin.

OBJECTIVE: Heparin inhibits vascular hypertrophy in angiotensin-induced hypertension, in addition to its well-known role in inhibiting injury-induced vascular smooth muscle proliferation. We tested whether hypertension and vascular hypertrophy could be reduced by heparin independently from the renin-angiotensin system. METHODS: Rats were made hypertensive with a one-kidney, one-clip (1K1C) procedure and received heparin from osmotic minipumps (0.3 mg/h per kg i.v.) or saline vehicle for 2 weeks. Blood pressure was measured by the tail-cuff method and vessel cross-sectional area was measured by morphometry in the aorta and mesenteric arteries. Proliferation was assessed with bromodeoxyuridine labelling. RESULTS: Blood pressure elevation and cardiovascular hypertrophy were evident in 1K1C rats. The media of mesenteric arteries was increased by 25%, and the media : lumen ratio by 35%, in hypertensive rats. DNA synthesis by smooth muscle cells in the mesenteric arteries was increased sevenfold in renal hypertension. Heparin treatment did not influence either the increase in blood pressure, the cardiovascular hypertrophy response or hypertension-mediated proliferation of arterial smooth muscle cells. CONCLUSIONS: These data suggest that the vascular hypertrophy mechanisms operating in 1K1C renal hypertension are not inhibited by heparin and thus are different from those in angiotensin-mediated hypertension. Identifying such mechanisms in the future will be important for devising appropriate intervention strategies in angiotensin-independent forms of vascular hypertrophy.

Angiotensin II↗
PubMedDate not supplied

Increased hypothalamic noradrenergic activity in one-kidney, one-clip renovascular hypertensive rats.

To further define central and peripheral sympathetic nerve activity in the one-kidney and two-kidney, one-clip models of renovascular hypertension, plasma catecholamines and regional brain norepinephrine of these models were compared with the activities of their brain biosynthetic enzymes: tyrosine hydroxylase (TYH) and dopamine-beta-hydroxylase (DBH). Findings in the groups of 20 one-kidney and 17 two-kidney female Wistar rats were compared with those in 10 sham-operated rats. Systolic blood pressure, measured indirectly, and the mean arterial pressure, measured directly from the femoral arteries, verified development of renovascular hypertension in both the one and two-kidney animals. Plasma norepinephrine increased from 248 +/- 46 to 401 +/- 66 pg/ml in the one-kidney group only (p < 0.001). Hypothalamic TYH and DBH activities of the one-kidney animals were 48 and 34% greater than those of the two-kidney animals and 28 and 39% greater than the sham-operated animals. The multiple t-test indicated significant differences between the mean hypothalamic THY of the one- and two-kidney groups and between the hypothalamic DBH of the one-kidney animals and those of the two-kidney and sham groups (alpha = 0.05). Moreover, the mean norepinephrine content of the hypothalamus in the one-kidney animals was 66% greater than that of the two-kidney and sham groups (p < 0.05). These findings suggest that central noradrenergic pathways of the hypothalamus may be involved in the genesis of one-kidney renovascular hypertension.

Animals↗
PubMed1994

Alpha 1-adrenoceptor subtypes mediating adrenergic vasoconstriction in kidney, one-clip Goldblatt and deoxycorticosterone acetate-salt hypertensive rats.

We characterised the functional alpha 1-adrenoceptors involved in mediating adrenergic vasoconstrictor responses in kidney of two-kidney one-clip (2K1C) Goldblatt and deoxycorticosterone acetate (DOCA)-salt hypertensive rats. In sodium pentobarbital-anaesthetised rats, frequency- and dose-dependent renal vasoconstrictor responses were obtained by direct electrical renal nerve stimulation, close renal arterial administration of phenylephrine (PE), and methoxamine. Administration of amlodipine, a dihydropyridine calcium channel antagonist (bolus dose of 200 and 400 micrograms/kg and an infusion of 50 and 100 micrograms/kg/h, respectively) and the alpha 1-adrenoceptor antagonist 5-methylurapidil (5 micrograms/kg plus 1.25 micrograms/kg/h and twice this dose) suppressed renal nerve-, PE-, and methoxamine-induced vasoconstrictions 14-70% (p < 0.05-0.001) in 2K1C Goldblatt and DOCA-salt hypertensive rats. The alpha 1B-adrenoceptor alkylating agent, chloroethylclonidine (5 micrograms/kg plus 1.25 micrograms/kg/h and twice this dose) caused significant attenuation (p < 0.001) of renal nerve-induced vasoconstriction by 19-23% in DOCA-salt hypertensive rats but did not affect PE- and methoxamine-induced vasoconstriction in either 2K1C Goldblatt or DOCA-salt hypertensive rats. In contrast, in 2K1C Goldblatt rats vasoconstrictor responses were potentiated by renal nerve stimulation and methoxamine. The data show that the functional renal postjunctional alpha 1-adrenoceptors on the vasculature of both hypertensive models are primarily of the alpha 1A-subtype, as reflected by their sensitivity to amlodipine and 5-methylurapidil. Moreover, an interaction appears to occur between the alpha 1-adrenoceptor subtypes at renal vessels in 2K1C Goldblatt hypertensive rats.

Adrenergic alpha-Antagonists↗
PubMed2003

Hemodynamic and cardiac anti-hypertrophic actions of clonidine in Goldblatt one-kidney, one-clip rats.

In congestive heart failure, the chronic sympathetic hyperactivity contributes to a poor prognosis. In this respect, clonidine, a centrally acting sympathoinhibitory drug, has previously been tested in clinical trials. The aim of the current study was to evaluate the effects of clonidine on morbidity and mortality in an experimental model of cardiac hypertrophy associated with hypertension, renal failure, and intense sympathetic activation. One-kidney, one-clip Goldblatt hypertensive rats were treated orally with clonidine (200 microg/kg/d) during 30 days and were compared with untreated rats and with sham-operated animals. Cardiac hemodynamics, left ventricular volume and elasticity, cardiac morphometry and histology, and renal function were evaluated. A survival study was also performed. Clonidine normalized cardiac function, ventricular stiffness, and prevented ventricular structural remodeling. Moreover, despite a marked renal function impairment, survival of the animals was increased in the clonidine group. The centrally acting sympathoinhibitory drug clonidine exhibited marked cardioprotective properties. This study emphasized the interest of evaluating drugs whose aim is to treat congestive heart failure, in an experimental model of cardiac and renal failure.

Animals↗
PubMed1999

Germ cells may survive clipping and division of the spermatic vessels in surgery for intra-abdominal testes.

PURPOSE: Laparoscopy is a well described modality that provides an accurate visual diagnosis upon which further management of intra-abdominal testes may be based. Laparoscopic ligation of spermatic vessels as stage 1 of the procedure is a natural extension of laparoscopy. A staged approach provides adequate viability of the intra-abdominal testis. However, it is uncertain whether the more sensitive germ cells survive this procedure in addition to the Sertoli and interstitial cells of the human testis. Survival of germ cells is a prerequisite of later fertility potential. MATERIALS AND METHODS: We studied 17 nonpalpable testes in 10 patients 1 year and 7 months to 13(1/2) years old. Results of testicular biopsies of 13 intra-abdominal testes taken at stages 1 and 2 of surgery were available for histological comparison. RESULTS: Median number of spermatogonia per tubular cross section of the biopsies taken at stage 2 was slightly lower (0.03) compared to the median number at stage 1 (0.06) of the operation but this difference was not significant (p = 0.2031). CONCLUSIONS: Our study shows that the spermatogonia may survive clipping and division of the spermatic vessels, although the number of spermatogonia per tubular transverse section decreases slightly.

Adolescent↗
PubMed1990

Temporary balloon occlusion of a proximal vessel as an aid to clipping aneurysms of the basilar and paraclinoid internal carotid arteries: technical note.

One aneurysm of the basilar artery and three large, paraclinoid aneurysms of the internal carotid artery (ICA) were treated with the aid of intraoperative temporary balloon occlusion of the vessel. Optimal clip placement was confirmed using intraoperative angiography. This technique provided excellent proximal vascular control and for the large aneurysms of the paraclinoid ICA obviated the need for surgical exposure of the ICA in the neck. We think this is a useful adjunct in the surgical management of aneurysms of both the basilar artery and proximal ICA.

Adult↗
PubMed1991

Tuberothalamic infarct after division of a hypoplastic posterior communicating artery for clipping of a basilar tip aneurysm: case report.

The authors present a case of a tuberothalamic infarct subsequent to division of the posterior communicating artery for clipping of a high-lying aneurysm of the basilar bifurcation using the pterional approach. In view of this clinical observation and some particular aspects of the microsurgical anatomy of the perforating vessels of the posterior communicating artery, we conclude that interrupting this parent vessel carries a significant risk of infarction.

Aged↗
PubMed1996

Aneurysm clipping after endovascular treatment with coils: a report of eight patients.

Between January 1990 and December 1994, patients with subarachnoid hemorrhage related to ruptured aneurysms who were referred to our institution were treated by neurosurgical and neuroradiological teams. In each patient, the respective indications for neurosurgical or endovascular treatment were discussed, taking into consideration patients' age and the morphological and topographical aneurysm features. We report eight cases of patients with subarachnoid hemorrhage who underwent operations after primary endovascular procedures (Hunt and Hess scores III, IV, and V). The indications for surgical treatment were as follows. First, deliberate partial occlusion of the aneurysm (two aneurysms of the internal carotid artery and one aneurysm of the anterior communicating artery) was performed to obtain only partial clotting of the aneurysm sac by free coils. However, this procedure was discontinued in favor of the use of Guglielmi detachable coils. The second indication was partial occlusion after an endovascular procedure (two aneurysms of the middle cerebral artery and one internal carotid artery aneurysm). The third indication was re-expansion of the aneurysm 1 year after the endovascular treatment (one middle cerebral artery aneurysm). The final indication was secondary rupture of the aneurysm sac and false aneurysm around the migrating coil (one aneurysm of the pericallosal artery). During surgery, the aneurysm sac appeared translucent. The coils bulged out and stretched the aneurysm sac. One ruptured the membrane leading to a subarachnoid hemorrhage during the endovascular procedure. No hemorrhage occurred during the surgical clipping. Aneurysm obliteration was easily performed, especially when the packing was partial, but was very difficult when the complete aneurysm closure led to a stenosis of the parent vessel. A giant sylvian aneurysm rest, visible only with angiography, was left untreated. This series illustrates an original experience, which led us to conclude that aneurysm surgery with coils in place is not as difficult as is often thought.

Adult↗
PubMed1998

Treatment of subdural effusion with hydrocephalus after ruptured intracranial aneurysm clipping.

OBJECTIVE: This study was conducted to determine whether a ventriculoperitoneal shunt alone was effective in treating subdural effusion with hydrocephalus. METHODS: Using only a ventriculoperitoneal shunt, we successfully treated eight patients who had subdural effusion with hydrocephalus after ruptured intracranial aneurysmal clipping, despite ventricular deformity and midline shift. RESULTS: For all of the patients, both the subdural effusion and ventriculomegaly subsided and clinical symptoms lessened after surgery. CONCLUSION: Ventriculoperitoneal shunting alone is an effective and satisfactory procedure; no subdural peritoneal shunt is needed for patients with subdural effusion accompanied by hydrocephalus. To-and-fro communication between the subdural effusion and ventricles is considered to be present in these patients. When selecting the treatment for subdural effusion, it is important to consider whether hydrocephalus (disturbance of cerebrospinal fluid circulation) is present.

Adult↗
PubMed2002

Intraoperative assessment of aneurysm clipping using magnetic resonance angiography and diffusion-weighted imaging: technical case report.

OBJECTIVE AND IMPORTANCE: To use intraoperative magnetic resonance imaging, including magnetic resonance angiography and diffusion-weighted imaging, to monitor the surgical treatment of a patient with an intracranial aneurysm. TECHNIQUE: Intraoperative imaging was performed with a ceiling-mounted, mobile, 1.5-T magnet (developed in collaboration with Innovative Magnetic Resonance Imaging Systems, Inc., Winnipeg, MB, Canada) that included high-performance 20-mT/m gradients. Pre- and postclipping, intraoperative, T1-weighted, angiographic and diffusion-weighted magnetic resonance images were obtained from a patient with an incidental, 8-mm, anterior communicating artery aneurysm. RESULTS: T1-weighted images demonstrated brain anatomic features, with visible shifts induced by surgery. Magnetic resonance angiography demonstrated the aneurysm and indicated that, after clipping, the A1 and A2 anterior cerebral artery branches were patent. Diffusion-weighted studies demonstrated no evidence of brain ischemia. CONCLUSION: For the first time, intraoperative magnetic resonance imaging has been used to monitor the surgical treatment of a patient with an intracranial aneurysm.

Humans↗
PubMed1997

A case report on drug screening of nail clippings to detect prenatal drug exposure.

In a case of a sudden infant death syndrome-related death of a 3-month-old infant, nail clippings were positive for cocaine by gas chromatography-mass spectroscopy analysis that revealed a prenatal exposure to the drug substance. In utero exposure to drugs has been investigated using amniotic fluid, neonatal urine, meconium, and hair samples. Nail analysis offers some advantage over hair analysis because of its continuous growth and persistence after delivery. Nail material is easy to sample in suitable amounts. Currently, the cocaine finding cannot be related to the underlying cause of death. However, this observation indicates that nail analysis may be a new and valuable tool to screen newborns for intrauterine drug exposure. In addition, it can help collect information on the prevalence of possible embryotoxic effects and the link to postnatal manifestations of different dysfunctions in infants who are born by drug abusing mothers.

Cocaine↗
PubMed1997

Combined cesarean section and clipping of a ruptured cerebral aneurysm: a case report.

We present a case of subarachnoid hemorrhage due to a ruptured cerebral aneurysm of the right internal carotid artery in a patient at 34 weeks of gestation (G2P1). A combined surgical procedure (cesarean section followed by clipping of the aneurysm) was performed with good maternal and fetal outcome. The differential diagnosis, the timing of neurosurgery, and the anesthetic techniques used are discussed.

Adult↗
PubMed2003

Anesthetic management for clipping a giant basilar artery aneurysm with moderate hypothermia, extracorporeal circulation assistance, and propofol infusion.

A 65-year-old female patient underwent surgery to clip a giant basilar artery aneurysm with closed-chest extracorporeal circulation using femorofemoral bypass. Moderate hypothermia (27 degrees C-30 degrees C), retention of spontaneous circulation, and propofol infusion (3-5 mg. kg(-1). h(-1)) were used under general anesthesia. Blood outflow via femoral vein was sufficient to maintain cardiopulmonary bypass and to induce hypothermia. Hemodynamics were controlled with dopamine and noradrenaline. In this case, extracorporeal circulation under moderate hypothermia was used to assist rather than substitute for spontaneous circulation, and spontaneous circulation was maintained at all times. We think that this method had advantages over deep hypothermic circulatory arrest with regard to intraoperative risks and postoperative complications.

Aged↗
PubMed2003

Evaluation of a vessel sealing system, bipolar electrosurgery, harmonic scalpel, titanium clips, endoscopic gastrointestinal anastomosis vascular staples and sutures for arterial and venous ligation in a porcine model.

PURPOSE: We assessed the usefulness of the LigaSure (Valleylab, Boulder, Colorado) vessel sealing system for vascular control during laparoscopic surgery and compared it with other available hemostatic modalities. MATERIALS AND METHODS: A total of 31 domestic pigs were divided into 5 groups. In groups 1 and 2 the vessel sealing system was compared with titanium clips and Endo-GIA (United States Surgical, Stamford, Connecticut) staples. In group 3 the vessel sealing system was compared with standard Klepinger (Karl Storz, Culver City, California) bipolar forceps. In group 4 the harmonic scalpel and Trimax (United States Surgical) bipolar forceps were compared. In group 5 in vivo laparoscopic application of the vessel sealing system was evaluated. RESULTS: The 5 mm. laparoscopic vessel sealing system sealed arteries up to 6 mm. and veins up to 12 mm. in diameter at supraphysiological bursting pressure. We evaluated 13 arteries with a diameter of 6 mm. or less at a mean bursting pressure of 662 mm. Hg (range 363 to 1,985) and 11 veins with a diameter of 12 mm. or less with a mean bursting pressure of 233 mm. Hg (range 63 to 440). Collateral tissue damage extended 1 to 3 mm. from the application site. Standard bipolar energy with Klepinger and Trimax forceps was less reliable and in some cases vessel sealing could not be accurately assessed before vessel division. Collateral tissue injury was 1 to 6 mm. The harmonic scalpel did not reliably seal vessels larger than 3 mm. but resulted in the least acute collateral tissue injury of 0 to 1 mm. CONCLUSIONS: In the porcine model the LigaSure system is a viable option for laparoscopic management of arteries up to 6 mm. and veins up to 12 mm. in diameter.

Anastomosis, Surgical↗
PubMed2001

Clipped random wave analysis of anisometric lamellar microemulsions.

Small-angle neutron scattering experiments were performed on C10E4-D2O-octane (where C10E4 is tetraethylene glycol monodecyl ether) anisometric microemulsions in the lamellar phase at a constant surfactant volume fraction of 20% and at the hydrophile-lipophile balance temperature of 22.5 degrees C. The results were analyzed using a clipped random wave model with a specific spectral distribution function developed by us previously. This enabled us to generate three-dimensional morphologies of the microemulsions, which showed clearly that in sufficiently anisometric microemulsions the oil-water interface was no longer connected. At large anisometry isolated regions of oil or water were found, and the transition from a bicontinuous structure at isometry to these isolated micelles far from isometry goes through an intermediate cylindrical morphology when the oil-to-water or water-to-oil ratio is around 4 to 1. We further computed the joint distribution function of the mean curvature H and Gaussian curvature K of the entire oil-water interface for each anisometric microemulsion. In particular, we show the distribution of , , and - (2) for different isolated regions within an oil-rich microemulsion at an oil-to-water ratio of 85% to 15%. These distributions allowed us to prove that the isolated regions formed in highly anisometric microemulsions were small and had spherical topology.

Journal Article↗