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At least 37 records · Page 2Linked to original sources

PubMed1979

Effect of renal vein constriction on the localization of immune complexes in the kidney.

To determine the effect of renal venous constriction on the localization of immune complexes in the kidney, we performed unilateral renal venous constriction in 19 male albino rabbits 7 days after they were given an i.v. bolus (250 mg/kg) of bovine serum albumin (BSA) to induce the development of serum sickness nephritis. The rabbits were sacrificed on day 12 after BSA administration. Renal histology was evaluated by (1) light microscopy, with semiquantitative grading and enumeration of glomerular nuclei and (2) fluorescent microscopy. Six rabbits were nonresponders and did not exhibit nephritis. The remaining 13 rabbits had differential degrees of severity of nephritis between the control and experimental kidneys as assessed by light microscopy (in 7 rabbits) and by fluorescent microscopy (in 12 and 9 rabbits when examined for deposits of IgG and C3, respectively). In all instances, the experimental kidney (with the constricted vein) showed less severe alterations. The degree of protection appeared to correlate with the degree of renal venous constriction, as manifested by tubulointerstitial changes [rs = 0.77, P less than 0.01). We concluded that renal venous constriction exercises a protective effect on the impaction of immune complexes in the glomeruli and development of acute serum sickness nephritis.

Animals↗

PubMed1992

Protein synthesis in pulmonary, cardiac, and skeletal muscle in acute hypertension induced by aortic constriction in the rat.

OBJECTIVE: The aim was to investigate nucleic acid composition and rates of protein synthesis in cardiopulmonary tissues and skeletal muscle in response to hypertension induced by aortic constriction. METHODS: After five days of abdominal aortic constriction, protein, RNA, and DNA contents were measured in the lung, the left and right atria, the left and right ventricles, and gastrocnemius muscle from young male Wistar rats weighing 120-140 g. Rates of protein synthesis were also measured in these tissues with L[4-3H]phenylalanine. RESULTS: Aortic constriction significantly increased the right atrial weight and in contrast reduced the lung weight, compared to pair fed and sham operated controls. The wet weights of all other tissues were unaffected. The concentrations of right atrial proteins, RNA, and DNA were also significantly reduced though total protein, RNA, and DNA contents were unaltered. The left ventricular RNA concentration increased and there were variable alterations in protein and DNA composition. The protein, RNA, and DNA compositions of the other tissues showed patterned responses, which included reductions in lung and skeletal muscle DNA concentrations, reductions in the skeletal muscle RNA/DNA ratio, and a decrease in the lung protein/DNA ratio. In response to aortic constriction there were increases in the left ventricular fractional rate of protein synthesis in mixed, high salt (myofibrillar), and low salt (sarcoplasmic) fractions. Rates of protein synthesis in all other regions of the heart, lung and skeletal muscle were not significantly changed. CONCLUSIONS: We conclude that in abdominal aortic constriction, the left ventricles display early adaptive responses without any concomitant change in mass. Those regions of the rat cardiopulmonary system which are not directly exposed to the acute pressure overloading, ie, right atrium, lungs, and skeletal muscle, also show disturbances.

Acute Disease↗

PubMed1978

Tracheal constriction by morphine and by fentanyl in man.

The effects of morphine and fentanyl on tracheal smooth muscle tone were studied in 38 patients during induction of anesthesia. Endotracheal tube cuff pressure was used to measure tracheal tone. Anesthesia was maintained with nitrous oxide, 70 per cent in oxygen, and pancuronium and ventilation was controlled with a respirator. Morphine, 0.5 mg/kg, produced a biphasic response, initially causing tracheal dilatation and then tracheal constriction. Ten minutes after morphine injection, cuff pressure increased to significantly (21 +/- 8 per cent) above control. Morphine-induced tracheal constriction could be completely blocked by the prior administration of atropine, 0.5 mg. Fentanyl, 0.006 mg/kg, also produced significant tracheal constriction, cuff pressures increasing to 44 +/- 11 per cent above control at 10 min. Fentanyl-induced tracheal constriction could be blocked by pretreatment with droperidol, 0.25 mg/kg. At equianalgesic doses, morphine and fentanyl produced similar tracheal constriction.

Adult↗

PubMed1976

Usefulness of systolic time intervals in differential diagnosis of constrictive pericarditis and restrictive cardiomyopathy.

Systolic time intervals in 15 patients with constrictive pericarditis and seven patients with restrictive cardiomyopathy were compared in order to assess their value in the differential diagnosis of the two disorders. Clinical examination had failed to make the distinction. Right heart catheterization was helpful in diagnosing restriction but failed to differentiate patients with constrictive pericarditis from those with restrictive cardiomyopathy. The systolic time intervals clearly separated the two groups. The PEP/LVET was normal in all patients with constrictive pericarditis (0.34 +/- 0.01) and abnormal in all patients with restrictive cardiomyopathy (0.70 +/- 0.09, P less than 0.001). In 13 patients (five with restrictive cardiomyopathy and eight with constrictive pericarditis) the results of quantitative left ventricular angiocardiography were available. A high correlation (r=-0.90, P less than 0.01) between the PEP/LVET and the ejection fraction confirmed the validity of the PEP/LVET as a measure of left ventricular performance in these patients. Thus the systolic time intervals clearly distinguished between constrictive pericarditis and restrictive cardiomyopathy and are a reliable non-invasive technique for making the difficult differential diagnosis.

Adult↗

PubMed1978

Effects of graded coronary constriction on regional oxygen and carbon dioxide tensions in outer and inner layers of the canine myocardium.

This study was undertaken to investigate the effects of graded coronary constriction on regional gas tensions of the myocardium. In 12 open chest dogs, tissue carbon dioxide (PtCO2) and oxygen (PtO2) tensions were measured simultaneously in outer and inner layers of the myocardium using a mass spectrometer. In normal condition, higher PtO2 and lower PtCO2 were observed in outer layer than in inner layer. With application of coronary constriction, increase in PtCO2 and decrease in PtO2 were observed in both layers of the myocardium, but the response to the ischemic stimuli by applying coronary constriction in inner layer was different from that in outer layer. Severe coronary constriction, more than 90% in its diameter, was necessary to produce significant changes in both gas tensions in both layers of the myocardium. Decrease in PtO2 was found in the condition of less severe coronary constriction and to be greater in inner layer than in outer layer of the myocardium. In terms of the changes in PtCO2, inner layer was also more susceptible to the ischemic stimuli than outer layer. The greater and earlier elevation of PtCO2 in inner layer than in outer layer is regarded as one of the possible mechanisms of the reduction of myocardial contraction in the early stage of myocardial ischemia.

Animals↗

PubMed1992

[Acute posterior interosseous nerve paralysis with constrictions possibly due to twists in the nerve trunk].

This report is concerning a case of acute spontaneous paralysis of the posterior interosseous nerve (P.I.O.N.), possibly caused by twists in the nerve trunk, in a 23-year-old woman. The subject felt a tingling pain over the lateral epicondyle of the right forearm when grasping and lifting a basin, and noticed that the fingers of the right hand could not be extended three days later. The fingers of the left hand also experienced paralysis 3 months after the first injury when she pronated and extended left forearm. Neurological examination revealed bilateral P.I.O.N. paralysis. When, after a period of time, the bilateral P.I.O.N. paralysis had not improved, surgical exploration of both P.I.O.N. was performed. It revealed that the right P.I.O.N. underwent a severe constriction at 2 cm proximal to the superficial portion of the supinator muscle, and that the proximal portion of the right nerve was swollen. The constricted portion of the right nerve was resected 5 mm in length, and nerve suturing was performed. The left P.I.O.N. was also constricted at the same location, and was found to be a sausage-like neurinoma with two constrictions. In the histological examination of the right resected P.I.O.N., edema of the interstitial tissue and a great number of regenerating cluster formations, including swollen axons, were observed proximal to the constriction. Distal to this, severe Wallerian degeneration was found. These histological findings were the same as those of chronic compression neuropathy. The authors reviewed and analysed reports on 20 other cases of P.I.O.N. paralysis that had compressions at 2 cm proximal to the superficial portion of the supinator muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1992

Pupillary constriction in response to light in rodents, which does not depend on central neural pathways.

We show here that the widely held belief that reflex constriction of the mammalian pupil in response to light depends exclusively upon neural pathways between eye and brain is in need of revision. We investigated the response of the pupil to light in dark-adapted rodents (golden hamsters; hooded rats; albino rats) subjected to a variety of surgical and pharmacological interventions designed to destroy or block all of the neural pathways and structures through which the reflex could be mediated. The interventions included bilateral intraorbital optic nerve section, or unilateral intracranial optic nerve section with enucleation of the contralateral eye, combined in some cases with bilateral removal of the superior cervical ganglia and/or pinealectomy; topical application of atropine; intraocular injection of tetrodotoxin (TTX). Golden hamsters and hooded rats, but not albino rats, retained an effective constriction of the pupil in response to light after all of these interventions, although the constriction was less and slower than in normal animals. These findings show that hamsters and hooded rats have both a neurally mediated fast light reflex that can be eliminated by severing connections between eye and brain, by blockade of cholinergic transmission to iris smooth muscle, and by blockade of action potentials by TTX; and a local, slower constriction in response to light, which remains after all these procedures. We have also confirmed previous observations of Bito and Turansky (1975) that pupillary constriction in response to light occurs in isolated in vitro anterior chamber preparations of hamster and hooded rat eyes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Pupillary constriction during forceful eyelid closure.

Pupillary constriction during forceful eyelid closure was investigated in 30 normal subjects. The right eye of each subject was filmed with an infrared-sensitive television camera in darkness before, during, and after eyelid closure. Clinically detectable constrictions were found in nine of the 30 subjects (30%). No significant correlation was found between amplitude of constriction and age of subject or baseline pupillary diameter. Forceful eyelid closure should be considered as a technique to elicit pupillary constriction in patients with a poor near response, but many subjects will have no detectable constriction using this maneuver.

Adult↗

PubMed1992

The use of mesh-tube-constricted dilated or varicose veins as arterial bypass conduit.

In general, dilated and varicose veins are not used as arterial bypass grafts despite their physiological endothelial lining. A uniform small diameter may be achieved by inserting such veins into mesh tubes. To test the degree to which dilated veins can be constricted without forming folds, in-vitro and experimental investigations were performed before such composites were used for clinical reconstructive surgery. Ovine jugular veins with a diameter of 15 mm were inserted into 6 mm tubes. After casting in paraffin wax none of the specimens showed folds on the flow surface. In 12 sheep pairs of mesh-constricted jugular veins and native femoral veins were implanted as femoropopliteal bypass grafts. Six animals were killed at 6 months and 6 at one year. All bypasses remained patent and none showed signs of obstruction caused by folds or anastomotic hyperplasia at angiographic control. Intimal hyperplasia was significantly reduced from 416 +/- 143 microns in the midportion of native vein grafts to 231 +/- 76 microns (p = 0.0001 paired t-test) in constricted veins as well as at the anastomoses (358 +/- 256 microns vs. 180 +/- 73 microns; p = 0.008). Partially or totally mesh-tube-constricted varicose veins were used for infrainguinal reconstructions in 19 patients and for coronary revascularization in 3. All grafts showed an even calibration at control angiography. As constriction does not lead to internal folds, varicose or dilated veins may be used successfully as bypass grafts after insertion into mesh tubes. The external reinforcement reduces the intimal hyperplasia within the graft and also reduces anastomotic hyperplasia.

Aged↗

PubMed1978

The effects of ureteral occlusion and renal venous constriction on kidney kallikrein-kinin and prostaglandin systems in dogs.

The intrarenal pressure was raised to 40--50 mmHg by ureteral occlusion or by renal venous constriction in anesthetized dogs loaded with 10% mannitol in saline and with a urine flow of approximately 1 ml/min/kidney. Both manoeuvres produced vasodilation and decreased urine creatinine excretion (GFR). Ureteral occlusion was associated with a marked antinatriuresis, which contrasted the variable decrements in sodium excretion during renal venous constriction. Ureteral occlusion did not affect urine excretion of kallikrein or kinins, whilst renal venous constriction decreased urinary kallikrein excretion, yet markedly increased urinary kinin excretion. Ureteral occlusion and renal venous constriction comparably increased urine prostaglandin (E-like) excretion by a presumably pressure dependent mechanism. Inhibition of prostaglandin synthesis by indomethacin abolished the vasodilation during renal venous constriction and this was accompanied by marked reductions of urinary creatinine (GFR) and kallikrein excretions, whilst the kinin excretion was enhanced as observed before the administration of indomethacin.

Animals↗

PubMed1979

Effect of graded coronary constriction on the flow reserve in regional myocardium in dog.

Effects of coronary constriction on the flow reserve of regional myocardium were studied in the anesthetized open-chest dogs. Regional myocardial blood flow (RMBF) was continuously measured using heated crossthermocouple method. Left circumflex coronary artery (LCX) was constricted gradually with a screw type constrictor. The coronary constriction decreased subendocardial myocardial blood flow, while subepicardial myocardial blood flow was not affected until reactive hyperemia in LCX nearly disappeared. Recovery and arrival to peak flow rate of RMBF following the release of 15-second's occlusion of LCX were progressively delayed with an increase in the constriction, especially in the subendocardial myocardium. Repayment of flow debt, however, was remained relatively well since the duration of reactive hyperemia in RMBF was prolonged by an increment of the constriction. From these findings, it might be concluded that in the heart with coronary stenosis recovery from ischemia was caused by prolonged duration of reactive hyperemia, and is suggested that the time required for recovery from ischemia or ischemic abnormalities after the cessation of stress might be an important marker for the severity of coronary insufficiency.

Animals↗

PubMed1979

Modification of induced airway constriction in healthy subjects.

Unlike asthmatics, healthy persons are relatively unresponsive to airway constrictors. By using partial expiratory flow-volume (PEFV) curves the authors have demontrated, in healthy subjects, dose-related decreases in flow rates following challenge with histamine and methacholine aerosols. With the use of semilogarithmic dose-response curves they have shown that 80 mg oral propranolol augmented, whereas oral pretreatment with 400 mg W10294A (an experimental bronchodilator) decreased, histamine and methacholine-induced airway constriction. However, 300 mg of orally administered aminophylline failed to modify the airway constrictor effects of histamine and methacholine. Moreover, variation was noted in induced airway constriction in healthy subjects with decreases in flow rates being greater in the morning than in the afternoon. The authors conclude that (1) propranolol augments whereas theophylline fails to prevent nonspecific induced airway constriction in healthy subjects. This suggests that the bronchodilator action of theophylline may be unrelated to its phosphodiesterase inhibitory activity, (2) control of volume history, by use of partial expiratory flow-volume curves, is useful in quantifying pharmacologic protection and augmentation of nonspecific induced airway constriction in healthy subjects and (3) conclusions resulting from observations of induced airway constriction in healthy subjects may be dependent upon the effects of diurnal variation.

Adult↗

PubMed1976

Blood flow in intact and constricted coronary arteries under the influence of ouabain.

The effects of ouabain on intact and experimentally constricted coronary arteries were investigated in anaesthetized, thoracotomized dogs. Ouabain decreased the blood flow in the intact artery without changing the flow per beat values and increased flow in the constricted artery. Since ouabain decreased left ventricular enddiastolic pressure, it is proposed that the drug-induced augmentation of flow in the constricted artery is related to an elevation of driving pressure to the endocardial layers of the myocardium which are supplied by the constricted artery.

Animals↗

PubMed1978

Effusive-constrictive hemodynamic pattern due to neoplastic involvement of the pericardium.

Eight patients with metastatic malignancy of the pericardium who demonstrated the hemodynamics of subacute effusive-constrictive pericarditis were studied. All patients had clinical evidence of cardiac tamponade due to malignant pericardial effusion and were referred for therapeutic pericardiocentesis. In six in whom pericardiocentesis was successfully performed, right atrial pressure remained elevated after pericardiocentesis and return of the intrapericardial pressure to zero; in these patients, hemodynamic data were initially compatible with tamponade but suggested constriction after removal of the pericardial fluid. In the remaining two patients, echocardiography revealed pericardial fluid, but attempted pericardiocentesis was unsuccessful. In these two patients, the hemodynamic data suggested pericardial constriction; subsequent pathologic examination revealed neoplastic involvement of the visceral pericardium. Thus, subacute effusive-constrictive pericarditis, previously recognized as a complication of tuberculosis or mediastinal radiation, may also be due to metastatic malignancy. The syndrome can readily be demonstrated when right heart catheterization is performed in conjunction with pericardiocentesis.

Cardiac Tamponade↗

PubMed1992

Coronary vascular and myocardial lesions due to experimental constriction of the abdominal aorta.

The development and evolution of arterial and myocardial lesions were morphologically evaluated in Wistar rats submitted to constriction of the abdominal aorta. The control (sham-operated) and operated groups were evaluated 1, 2, 4 and 6 weeks after surgery. The aorta-constricted groups developed arterial hypertension followed by myocardial hypertrophy evidenced from the first week onwards by the increase in ventricular weight and in the diameters of left and right ventricular myofibers. The histopathologic study of the myocardium revealed in aorta-constricted groups, since the first week, widespread necrotizing changes of the intramural coronary branches surrounded by multifocal areas of myofiber degeneration and necrosis. The lesions were more extensive in the wall of the right ventricle and were gradually replaced by scar tissue. At the 6th week patchy focal fibrotic scars were found scattered in the myocardium of both ventricles. There were no systemic lesions in aorta-constricted or sham-operated groups. The close association between the arterial and myocardial lesions shows that muscle necrosis and scars are due to ischemia. They may influence the contractile performance of the myocardium in this model of pressure-induced hypertrophy of the heart.

Animals↗

PubMed1977

Traumatic hemopericardium and chronic constrictive pericarditis.

Chronic constrictive pericarditis following traumatic hemopericardium has been reported in recent years, but it has not been reproduced experimentally in dogs. The present study attempted to produce posttraumatic constrictive pericarditis in 34 experimental animals. Hemopericardium by means of trauma to the epicardium or pericardium was produced by a sharp instrument or by the injection of autologous blood inside the pericardial sac. All animals were killed at intervals between 3 and 31 months. The animals in which hemopericardium was induced by injecting blood into the pericardial cavity showed no changes. The hemopericardium was completely resolved without noticeable residual trace. Animals having hemopericardium as a result of trauma evidenced a well-developed constrictive pericarditis that was documented clinically, hemodynamically, and histologically. These experimental findings indicate that chronic constrictive pericarditis may well be due to traumatic hemopericardium rather than to specific infection.

Animals↗

PubMed1975

Correlation of intra-arterial contrast stasis with flow patterns at constrictions, branches and bends: an experimental model.

Flow patterns at bends and branches have been studied in an easily constructed open channel model so as to determine whether zones of stasis and poor mixing at constrictions, bends and branches can be correlated with certain arteriographic appearances. At bends, spiral flow lines and static zones occur which resemble those seen occasionally in the aortic arch and carotid siphon. At branches, stasis occurs on the outer walls of the branch mouths both in the experiments and arteriography, and constrictions easily produce downstream stasis, previously demonstrated in both arteries and open-channel experiments. Upstream stasis, not previously recorded, can also occur in arteries and model associated with severe constrictions. Occasionally stasis may extend along the whole length of one wall of a vessel when there is a downstream constriction, resembling arteriographic appearances seen in the internal carotid artery in patients with raised intracranial pressure, in those undergoin hyperventilation and also in coronary and other arteries. Despite known rheological differences between blood and water, the experimental findings are thought to be meaningful, and to indicate that there are within arteries, areas where turbulent mixing forces are weak or absent, resulting in arterial stasis.

Angiography↗

PubMed1978

Angiocardiographic differentiation of constrictive pericarditis and restrictive cardiomyopathy due to amyloidosis.

The cineangiocardiograms and coronary angiograms of two cases of amyloidosis of the heart were compared to six cases of constrictive pericarditis. Three angiographic differentiating points were seen: (1) right ventricular free wall motion showed diastolic restriction in both disorders, whereas the crista supraventricularis, which moved normally in constrictive pericarditis, demonstrated restriction in amyloidosis; (2) ventricles in cases of constrictive pericarditis showed subtle further expansion during atrial systole after initial rapid filling (atrial kick), while in both cases of amyloidosis there was no motion during atrial systole; (3) pericardial thickening in constrictive pericarditis was demonstrated by failure of the distal coronary arteries to reach the surface of the cardiac image. In amyloidosis, the distal coronary arteries normally reached the periphery of the image. All three signs may be useful in differentiation, but the first is the easiest to evaluate. The right anterior oblique or posteroanterior view is the recommended projection.

Amyloidosis↗