Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Constriction”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources
PubMed1995

Role of nitric oxide in the development of thermal hyperesthesia induced by sciatic nerve constriction injury in the rat.

BACKGROUND: Nitric oxide (NO) has been shown to be involved in mediating nociceptive information transmission in the spinal cord. It is known that the N-methyl-D-aspartate receptor plays an important role in the development of the spinal facilitation evoked by a protracted small afferent input and that this effect is mediated at least in part by NO. Recently, it has been found that N-methyl-D-aspartate receptor-mediated spinal facilitation is crucial in the development of thermal hyperesthesia evoked by a nerve constriction injury. In the current study, we investigated the role of NO in the development of thermal hyperesthesia after a nerve constriction injury. METHODS: The Bennett and Xie model (four loose chromic gut ligations around the rat sciatic nerve) was used to examine the development of thermal hyperesthesia. An NO synthase inhibitor (N omega-nitro-L-arginine or N omega-nitro-L-arginine methyl ester hydrochloride), rat hemoglobin, or L-arginine was administered intrathecally 10 min before the nerve injury (pretreatment study) or 15 min after the nerve injury (posttreatment study). RESULTS: Pretreatment but not posttreatment administration of NO synthase inhibitor significantly delayed the development of thermal hyperesthesia. The effect of NO synthase inhibitor was reversed by the coadministration of L-arginine but not by the coadministration of D-arginine. Pretreatment with rat hemoglobin also delayed the development of thermal hyperesthesia. L-Arginine itself had no effect on the development of thermal hyperesthesia. CONCLUSIONS: NO may play an important role in the development of N-methyl-D-aspartate receptor-mediated spinal facilitation after a nerve constriction injury.

Animals↗
PubMed1981

Computed tomography in constrictive pericardial disease.

Thirteen patients with pericardial abnormalities and a question of constrictive hemodynamics underwent contrast enhanced cardiac computed tomography (CT). Those with clinical and catheterization evidence of restricted cardiac filling demonstrated three CT signs: a dilated IVC, a deformed ventricular contour, and an angulated interventricular septum. Patients with pericardial fluid, thickening, or calcification but without evidence of constriction showed none of these signs. Cardiac CT also defined sites of particular constriction for subsequent resection.

Adult↗
PubMedDate not supplied

The hemodynamic signs of constrictive pericarditis can be mimicked by tricuspid regurgitation.

A case with clinical and hemodynamic findings consistent with constrictive pericarditis is reported. At surgery, the pericardium was not thickened or adherent to the epicardial wall. As suggested by echocardiography, a diagnosis of severe tricuspid regurgitation was confirmed. This case illustrates that invasive hemodynamic findings consistent with a picture of pericardial constriction can be produced by processes other than constrictive pericarditis.

Aged↗
PubMedDate not supplied

Constrictive pericarditis versus restrictive cardiomyopathy: challenges in diagnosis and management.

This is the case of a patient who presented with severe right-sided heart failure due to diastolic dysfunction that caused a dilemma of differential diagnosis between restrictive cardiomyopathy and constrictive pericarditis. Restrictive cardiomyopathy was diagnosed based on noninvasive and invasive hemodynamic testing. However, the patient did not respond to therapy and succumbed to worsening heart failure and multiple comorbidities. Clinical features of right heart failure with edema, ascites, jugular venous distention, and tender hepatomegaly are commonly seen in clinical practice. When systolic function is determined to be normal, diastolic causes of heart failure must be ruled out. These include myocardial disorders with a broad range of pathologies leading to restrictive physiology, of which amyloidosis is a prototype. Pericardial disorders leading to diastolic heart failure are usually in the form of constrictive physiology, when pericardial tamponade is ruled out. Differentiation between restrictive and constrictive pathologies is often difficult and requires careful attention to hemodynamic and Doppler echocardiographic features. We report a case of severe right heart failure illustrating some of the complexities in decision-making and the importance of meticulous hemodynamic and ancillary testing in the diagnosis and treatment of this often fatal condition.

Aged↗
PubMed1992

Vacuum constriction devices: second-line conservative treatment for impotence.

Intracavernosal pharmacotherapy is not a universally successful treatment of impotence. Vacuum constriction devices are reported to be an effective non-operative alternative. This study investigated the value of these devices in 45 impotent men who had failed to become established on intracavernosal papaverine. Although 38 were able to obtain an erection-like state using a vacuum constriction device, only 12 were able to enjoy satisfactory sexual intercourse and, of these, just 7 men found them of sufficient benefit to warrant purchase. Success is not predicted by aetiology. Vacuum constriction devices are of some use, but a trial period of use should be allowed to each patient before purchase.

Adult↗
PubMed2005

Protein-losing enteropathy as the principal manifestation of constrictive pericarditis.

Constrictive pericarditis represents a rare cause of protein-losing enteropathy due to intestinal lymphangiectasia. We report the case of a patient with an atypical clinical presentation of constrictive pericarditis and protein-losing enteropathy as its principal manifestation; he was successfully treated with pericardiectomy. We conclude that, constrictive pericarditis should be considered in the presence of protein losing enteropathy and also, protein-losing enteropathy should be considered in the differential diagnosis of hypoalbuminemia.

Aged↗
PubMed1994

Doppler echocardiography in cardiac tamponade and constrictive pericarditis.

Doppler echocardiography has greatly facilitated the assessment of patients with compressive cardiac disease. Patients in whom cardiac tamponade or pericardial constriction are suspected should undergo a complete echocardiographic examination including careful Doppler analysis of transmitral flow and inflow through the hepatic vein or superior vena cava (SVC). Monitoring of both the electrocardiogram and the phase of respiration are an integral part of this examination. Patients with cardiac tamponade exhibit a > 25% reduction in E wave velocity during the first inspiratory cardiac cycle; they exhibit predominant systolic inflow through the hepatic vein or SVC (with a predominant X descent with little or no Y descent). In constrictive pericarditis the pattern of transmitral flow variation is comparable to that observed in cardiac tamponade, however, a prominent Y descent is often observed on hepatic vein or SVC Doppler study. Similar changes with respiration may be observed in mitral inflow in obese patients or in those with chronic obstructive pulmonary disease, however, in these conditions the nadir of E wave velocity is observed 2-3 cardiac cycles after the first inspiratory beat. Restrictive cardiomyopathy may produce a similar systemic venous flow pattern, but increased inspiratory flow reversals and lack of respiratory variation in transmitral flow velocity distinguish it from constrictive pericarditis.

Cardiac Tamponade↗
PubMedDate not supplied

Rapid development of fatal TB constrictive pericarditis after cardiac surgery.

We report the case of a 75-year-old male of Asian origin who developed TB constrictive pericarditis less than 6 weeks after CABG. He had no history of active TB, but did show a strong Heaf test reaction in 1987, following a period of weight loss. This was thought to be indicative of previous infection and was not actively treated. Cases of postcardiac surgery constrictive pericarditis have been reported in the literature, but to our knowledge, there is no report of development of TB constrictive pericarditis in such a short period following surgery.

Aged↗
PubMed1977

The occurrence and apparent effect on reproduction of a constriction of the vagina in the merino ewe.

The incidence and effect on reproduction of a constriction of the vagina was studied in 12 maiden merino flocks on 5 commercial properties in Western Australia. The overall incidence of the constriction was 11% with a range of from 2% to 27%. Ewes with a constriction of the vagina exhibited inferior reproductive capacity; fewer ewes lambed and of those that did fewer reared their lambs. A higher lamb mortality was recorded in lambs born to such ewes.

Animals↗
PubMed1992

Constrictive pericarditis in a mare: attempted treatment by partial pericardiectomy.

Chronic constrictive pericarditis was diagnosed in a 6-year-old Thoroughbred mare based on the clinical findings of right congestive heart failure, hyperechoic pericardium without pericardial effusion, and a dip-and-plateau shape of the right ventricular pressure curve with equilibration of the diastolic pressures in all cardiac chambers. Treatment was attempted by partial pericardiectomy using a right lateral thoracotomy approach. Because of severe epicardial involvement recurrence of the constrictive pathology was noted 6 weeks after the surgical procedure. However, in selected cases in which the disease process is limited to the pericardium, partial pericardiectomy may offer a mode of therapy in horses suffering from constrictive pericarditis.

Animals↗
PubMed1970

Value of reference tracings in diagnosis and assessment of constrictive epi- and pericarditis.

Reference tracings are of great value in the diagnosis and assessment of constrictive pericarditis. The Q-h interval in the jugular venous pulse tracing is strongly correlated with the mean right atrial pressure (r=0.91). The left ventricular ejection time, the Q-A2 interval, and the Q-h interval are independent during atrial fibrillation from the preceding diastolic filling interval. This differentiates constrictive pericarditis from valvular heart disease. Cases with haemodynamically significant constrictive epicarditis are characterized by a rapid evolution, absence of pericardial calcification and absence of an early diastolic filling sound, a dominant a wave in the jugular venous pulse tracing, and a high early diastolic ventricular pressure. The haemodynamic behaviour is similar to that found in cases with myocardial fibrosis.

Adolescent↗
PubMed1985

Constrictive pericardial disease: prognostic significance of a nonvisualized left ventricular wall.

Twenty-six patients with pericardial constriction confirmed by catheterization were studied by dynamic computed tomography (CT). The posterolateral wall of the left ventricular myocardium was not detected in five patients (19.2%). None had evidence of previous myocardial infarction on electrocardiogram or levocardiogram. In 16 patients, a pericardiectomy was performed to remove pericardial constriction. All five patients with nondetectable posterolateral walls of the left ventricle died at or immediately following surgery because of acute myocardial failure. Nonvisualization of the posterolateral wall of the left ventricle in patients with constrictive pericarditis suggests the presence of myocardial fibrosis or atrophy. Surgery is an extremely high risk in these patients.

Adult↗
PubMed1991

Perfused prenodal lymphatics are constricted by prostaglandins.

Prostaglandins may contribute to the control of lymph flow by affecting lymphatic vessel contractility. We measured the pressure in perfused prenodal lymphatic vessel in the paw of the anesthetized dog as affected by administration of prostaglandins E1, E2, F2 alpha or arachidonic acid. The forelimb was perfused at constant flow with blood obtained from a femoral artery. Systemic arterial, central venous, and forelimb vascular pressures were measured. When added to the lymphatic perfusate, all of the prostaglandins and arachidonic acid caused constriction of lymphatic vessels. Perfusion of prenodal lymphatics separated from downstream nodes and vessels showed that this constriction occurred primarily in prenodal vessels. However, only prostaglandin F2 alpha caused lymphatic constriction when infused into the blood to the forelimb. Because prostaglandins are a common component of the lymph leaving an area of tissue damage, these results are compatible with the possibility that prostaglandins, by directly affecting lymphatics, help modulate lymph flow following local injury.

Alprostadil↗
PubMed1984

Effects of meclofenamate on the renin response to aortic constriction in the rat.

This study examines the role of the renal prostaglandin system in stimulus-secretion coupling for renal baroreceptor-dependent renin release in the anesthetized rat. Changes in plasma renin activity (PRA) secondary to suprarenal aortic constriction were evaluated in groups of rats with a single denervated nonfiltering kidney (DNFK) with and without pretreatment with meclofenamate. Suprarenal aortic constriction was adjusted to reduce renal perfusion pressure to either 100 or 50 mmHg. In addition, similar experiments were performed in rats with a single intact filtering kidney. Inhibition of prostaglandin synthesis with meclofenamate failed to block or attenuate the increase in PRA in response to the decrement in renal perfusion pressure after both severe and mild aortic constriction for both the DNFK and the intact-kidney groups. The adequacy of prostaglandin inhibition was demonstrated by complete blockade with meclofenamate of the marked hypotensive and hyperreninemic responses to sodium arachidonate. The results in the DNFK indicate that in the rat, renal prostaglandins do not function as obligatory mediators of the isolated renal baroreceptor mechanism for the control of renin release. Also the findings in the intact filtering kidney suggest that prostaglandins are not essential in the renin response of other intrarenal receptor mechanisms that also are stimulated by a reduction in renal perfusion pressure.

Animals↗
PubMed1987

Sodium excretion in dogs with low-grade caval constriction: role of hepatic nerves.

Low-grade thoracic caval constriction will raise intrahepatic pressure without driving fluid from the vascular space as ascites. In eight such dogs where venous pressure was increased by 6.6 cmH2O, sodium balance studies showed a positive cumulative balance of 85 meq and a weight gain of 480 g over a 6-day period in the absence of any change in renal perfusion, glomerular filtration rate, central venous pressure, blood pressure, cardiac output peripheral vascular resistance, or plasma levels of aldosterone. Liver function tests, including bromosulfophthalein disappearance curves, were also normal. In dogs with either sham surgery, or subjected to equivalent venous hypertension of the abdominal vena cava or portal veins, there was a cumulative positive sodium balance of only 21-28 meq over a 2-day period. When the liver was completely denervated prior to performing the thoracic caval constriction, the sodium handling profile reverted to the same pattern as observed in sham controls, i.e., 22 meq cumulative sodium over a 3-day period. When the thoracic caval constriction was tightened to produce ascites, a LeVeen valve was inserted and the ascites mobilized. In response to 130 meq/day sodium diet, denervated dogs excreted the sodium load normally, whereas dogs with intact hepatic nerves retained sodium and developed anasarca. We conclude that intrahepatic baroreceptors may modulate sodium excretion in the presence of intrahepatic hypertension.

Aldosterone↗
PubMed2003

Impedance, gas mixing, and bimodal ventilation in constricted lungs.

To evaluate the effect of increasing smooth muscle activation on the distribution of ventilation, lung impedance and expired gas concentrations were measured during a 16-breath He-washin maneuver in five nonasthmatic subjects at baseline and after each of three doses of aerosolized methacholine. Values of dynamic lung elastance (El,dyn), the curvature of washin plots, and the normalized slope of phase III (S(N)) were obtained. At the highest dose, El,dyn was 2.6 times the control value and S(N) for the 16th breath was 0.65 liter(-1). A previously described model of a constricted terminal airway was extended to include variable muscle activation, and the extended model was tested against these data. The model predicts that the constricted airway has two stable states. The impedances of the two stable states are independent of smooth muscle activation, but driving pressure and the number of airways in the high-resistance state increase with increasing muscle activation. Model predictions and experimental data agree well. We conclude that, as a result of the bistability of the terminal airways, the ventilation distribution in the constricted lung is bimodal.

Administration, Inhalation↗