Intra-arterial Perfusion Research Articles

Does atrial natriuretic factor protect against right ventricular overload? I. Hemodynamic study

We studied the effects of synthetic atrial natriuretic factor (ANF, 28-amino acid peptide) on base-line perfusion pressures and pressor responses to hypoxia and angiotensin II (ANG II) in isolated rat lungs and on the following hemodynamic and renal parameters in awake, chronically instrumented rats: cardiac output (CO), systemic (Rsa) and pulmonary (Rpa) vascular resistances, ANG II- and hypoxia (10.5% O2)-induced changes in Rsa and Rpa, and urine output. Intra-arterial ANF injections lowered base-line perfusion pressures and blunted hypoxia- and ANG II-induced pressor responses in the isolated lungs. Bolus intravenous injection of ANF (10 micrograms/kg) into intact rats decreased CO and arterial blood pressures of both systemic and pulmonary circulations and increased Rsa. ANG II (0.4 micrograms/kg) increased both Rsa and Rpa, and hypoxia increased Rpa alone in the intact rats. ANF (10 micrograms/kg) inhibited both ANG II- and hypoxia-induced increases in Rpa but did not significantly affect the ANG II-induced increase in Rsa. The antagonistic effect of ANF on pulmonary vasoconstriction was reversible and dose-dependent. The threshold doses of ANF required to inhibit pulmonary vasoconstriction were in the same range as those required to elicit diuresis and natriuresis. The data demonstrate that ANF has a preferential relaxant effect on pulmonary vessels constricted by hypoxia or ANG II. Both the renal and the pulmonary vascular effects of ANF may represent fundamental physiological actions of ANF. These actions may serve as a negative feedback control system that protects the right ventricle from excessive mechanical loads.

Release of Atrial Natriuretic Factor from Intact and Hypophysectomized Rat Hypothalamic Expiants

Abstract Experiments examined release of atrial natriuretic factor (ANF), measured by radioimmunoassay, from acutely prepared explants of rat hypothalamus maintained in vitro by intra-arterial perfusion of artificial cerebrospinal fluid. Perfusates collected from intact preparations contained 6.1 +/- 0.6 pg (mean +/- SEM) of ANF per 2-min sample. Following a 3-min infusion of noradrenaline (60 muM), ANF release increased significantly (P<0.05) to 11.4+/-1.4 pg/sample. Media collected from hypophysectomized preparations showed the same basal ANF release (6.8 +/- 0.9 pg/sample) as intact preparations, but demonstrated no significant increase after noradrenaline infusions. Levels of spontaneous ANF release were not appreciably affected by the absence of the paraventricular nuclei and/or the anteroventral third ventricle area. Extracted material from the perfusate by reverse-phase high performance liquid chromatography revealed two main peaks of immunoreactive ANF: a small molecular weight form that coeluted with synthetic ANF (99-126) and with similar biological activity in a radioreceptor assay, and a larger molecular weight form with the same elution profile as the ANF (1-126) prohormone. These observations indicate that the ANF released from perfused rat hypothalamic explants contains distinct contributions from the hypothalamus (sites undetermined) and the neurointermediate lobe.

Oxygen radical scavengers improve vascular patency and bone-muscle cell survival in an ischemic extremity replant model.

We examined the use of oxygen radical scavengers in preventing the no-reflow phenomenon and improving bone-muscle cell survival in an ischemic extremity replant model. A total of 70 Lewis rat modified hindlimb replants were performed after specific periods of cold ischemia and intraarterial perfusion with either superoxide dismutase and catalase, specific oxygen free-radical scavengers, or a control solution. Ischemic hindlimbs treated with superoxide dismutase and catalase showed a statistically significant (p less than 0.05) improvement in vascular patency after prolonged cold ischemia when compared to controls. Histologically, experimental extremities demonstrated greater osteoblast, osteocyte, and muscle cell survival in replanted hindlimbs with patent vascular anastomoses. The perfusion of severed limbs and digits and free vascularized tissue transfers with superoxide dismutase and catalase after a period of ischemia has already occurred may prolong the ischemic "time window" tolerated for successful tissue survival.

Preventing oxygen free-radical injury in ischemic revascularized bone grafts.

Superoxide radicals have been shown to play a role in the cellular injury of reperfused ischemic tissues. We examined the protective effect of superoxide dismutase (SOD), a superoxide radical scavenger, on the reperfusion injury of replanted vascularized bone grafts after 4- and 8-hour periods of ischemia in a rat model. Histologic, fluorochrome, and histomorphometric analyses showed no difference between 4-hour superoxide dismutase-treated and control grafts, with both groups appearing viable. Similar analyses of the 8-hour ischemic grafts revealed both a qualitative and statistically significant quantitative difference (p less than 0.001) between the superoxide dismutase-treated and control grafts in parameters related to viability. Our results indicated that the administration of superoxide dismutase to free vascularized grafts by means of intraarterial perfusion after prolonged periods of warm ischemia significantly enhances the survival of these grafts.

Analysis in the Isolated Perfused Cat Pancreas of Factors Implicated in the Pathogenesis of Pancreatitis

This study describes the effect on the function and structure of the saline-perfused cat pancreas of factors implicated in the pathogenesis of pancreatitis (bile acid, ethanol, pancreatic enzymes) after their addition to the perfusion fluid or their instillation into the pancreatic duct. Instillation of trypsin or chenodeoxycholic acid, but not ethanol, into the pancreatic duct resulted in a profound suppression of secretory function. The leakage of perfusion fluid and amylase from the gland was also abruptly increased. Intraarterial perfusion of trypsin also inhibited secretin-induced flow and cholecystokinin evoked enzyme secretion. Intraarterial bile acid inhibited fluid flow but augmented enzyme secretion in a concentration-dependent manner. In addition, massive or focal parenchymal necrosis was caused by sustained intraarterial perfusion of bile acid or trypsin, respectively. Elastase and phospholipase A had little influence on pancreatic function or structure when added to the perfusion fluid. These findings show that pancreatic structure and function can be disturbed by potentially toxic factors administered not only via the ductal system but also via the vascular route, and consequently suggest that an "internal reflux" mechanism could be involved in the pathogenesis of pancreatitis in addition to a "ductal reflux" mechanism.

Atlas of hepatic arterial perfusion scintigraphy.

Tc-99m MAA intra-arterial perfusion studies are necessary to determine blood flow distribution for hepatic arterial chemotherapy. In this mini-atlas, examples selected from over 900 cases to illustrate important points to aid in a better understanding and interpretation of these studies with particular emphasis on diagnostic and therapeutic interventions are presented.

Mammalian endoneurial fluid: Collection and protein analysis from normal and crushed nerves

An elution procedure was developed for the extraction of endoneurial fluid from desheathed, rat sciatic nerves. The endoneurial fluid elutions (EFE) from normal and crushed nerves were evaluated for extracellular proteins by sodium dodecyl sulphate-pore gradient electrophoresis (SDS-PGE) after silver stain and after immune overlay following electrophoretic transfer to nitrocellulose using antisera to albumin (ALB), neurons specific enolase (NSE), and the major myelin glycoprotein (P 0). Afer removal of the epineurium/ perineurium, the EFE protein accounted for 3.6% (34–37 μg) of the total endoneurial protein which did not change with intra-arterial perfusion. The endoneurium was further fractionated to obtain an aqueous supernatant (S-I), and SDS-solubilized supernatant (S-II), and an SDS-insoluble fraction. SDS-PGE analysis revealed that the EFE has a distinctive protein composition relative to the other endoneurial fractions. A predominant band with M r of 64,000; 4 major bands with M r of 86,200, 61,000, 54,500 and 46,900; and several other minor bands were observed. The predominant band at 64,600 co-migrates with ALB and was demonstrated by immune overlay to be ALB, which was also the major protein in the S-I fraction. The uniqueness of the EFE was established by the absence of NSE, an enzyme marker for the cytoplasmic fraction of axons which was found to be present only in S-I (subunit M r= 49,600), the absence of P 0, and the distinctive protein profiles as determined by silver stain. Crush injury resulted in a progressive increase in the amount of protein found in the EFE as well as the S-I with a corresponding decrease in S-II protein as a function of time after crush (1, 2, 5, 10, 24, 48, 96, 168 h). Dramatic alterations in the protein profile were demonstrated in the EFE from crushed nerves after SDS-PGE indicating substantial changes in the endoneurium as a result of the axonal degeneration, demyelination, and breakdown of the blood-nerve barrier. Alterations in EFE proteins after crush were also observed by lectin overlay experiments after SDS-PGE. Analysis of EFE collected after crush for NSE and P 0 were negative. It is concluded that the distinctive pattern of EFE proteins identified from normal nerve will permit their further characterization as a separate endoneurial protein compartment. Such an elution procedure for collection of endoneurial fluid can readily be adapted to human sural nerve biopsies from patients with peripheral neuropathy for characterization of the appearance of new proteins which may be used as markers of disease activity.

Adenosine and Diltiazem

To determine the therapeutic effect of two vasodilators, adenosine and diltiazem, in mesenteric ischemia, 13 dogs were treated with an intra-arterial perfusion of the drugs after digitalis intoxication. Blood flow was restored to the control value after a dose of 2 micrograms/kg/minute adenosine or 5 micrograms/kg/minute diltiazem. The advantage of adenosine is that its effect begins and ends very rapidly, but because doses of more than 2 micrograms/kg/minute may cause a drop in blood pressure, strict pressure control is mandatory when the drug is applied clinically. Its limited use is appropriate, for example, when operative measures cannot be excluded. Diltiazem can be used for long-term therapy with a reduced risk of a drop in blood pressure.

Somatostatin Induces Ectopic Activity Fronts of the Migrating Motor Complex via a Local Intestinal Mechanism

To study the peripheral effect of somatostatin in dogs a tiny Silastic catheter was implanted in an almost terminal branch of the mesenteric artery, providing blood supply to a jejunal segment of 5-10 cm. In 4 dogs one catheter was implanted, perfusing a small bowel segment about 60 cm below the angle of Treitz; in 3 dogs two catheters were implanted, perfusing two small bowel segments about 30 and 60 cm below the angle of Treitz. The catheter was kept open by continuous perfusion with a diluted heparin solution by means of a portable insulin infusion pump fixed to the animal's protection jacket. Small bowel motility was recorded electromyographically. Experiments were started 2 wk after surgery and were performed in conscious fasted animals. Control experiments using intraarterial saline perfusion showed normal migrating motor complexes in the perfused segment. Intraarterial perfusion of somatostatin (50-200 ng/kg X h) induced ectopic activity fronts, which always started just distal to the perfused segment and progressed down the small bowel at a normal propagation velocity. During the occurrence of ectopic fronts no activity fronts were observed in the small bowel proximal to the perfusion site. Apart from ectopic fronts, normal activity fronts, starting in the duodenum and passing the perfused segment, were also observed. The most proximal part of the jejunum was more sensitive to intraarterial somatostatin than the more distal jejunum. Intravenous infusion of the same doses of somatostatin had no effect. Somatostatin, therefore, seems to induce ectopic fronts via a local mechanism. We propose that somatostatin is able to relieve the intestine locally from an inhibitory mechanism that prevents the development of activity fronts.

Influence of catecholamines on perilymph Po2.

In a previous study, a special rheological model of intra-arterial perfusion was used to examine the existence and effectiveness of vasomotor control of the cochlear vessels in guinea pigs. Catecholamines were injected intra-arterially into this animal model and the changes induced in the cochlear action potentials were examined. In this investigation, we used the same animal model and technique to measure the perilymph Po2 after perfusion of the cochlea with catecholamines. In addition, the effect of drainage of the CSF before infusion was examined. The results indicated that opening the labyrinth allows the escape of CSF through the patent cochlear duct. This may modify the concentration of the substance under study in the perilymph and cause inaccuracies in the data obtained.

Role of prostaglandins in the production of natriuretic factor by the isolated rat kidney.

The renal origin of natriuretic factor (NF) of high molecular weight (MW 45,000) has been previously demonstrated. Its role in the control of sodium excretion by the kidney has been strongly suggested. The aim of the present work was to study the relationship between NF and prostaglandins, which are known to modify the renal regulation of sodium. (1) The activity of NF, obtained by ultrafiltration and gel filtration from pooled plasma of salt-loaded rats, was tested on an isolated rat kidney perfused by a cell-free medium. A significant natriuresis was observed in the kidneys isolated either from normal rats or from indomethacin-pretreated rats after injection of NF. Moreover, a dose-response curve was obtained with increasing amounts of NF. (2) The ability of isolated rat kidney to produce NF was studied in two series of salt-deprived rats, the second series being pretreated with indomethacin. The production of NF by isolated kidneys was induced by addition of saline to the fluid perfusing kidneys isolated from normal or indomethacin-pretreated rats fed a salt-depleted diet. Before addition of saline, no natriuretic activity was detectable. After the addition of 0.9% NaCl, NF was only found in the perfusate from kidneys isolated from normal rats. Perfusate extracts from indomethacin-pretreated kidneys did not induce any significant rise in natriuresis. (3) Kidneys isolated from rats previously fed a free fatty acid-deficient diet and thus prostaglandin-depleted were unable to produce NF even if they were salt-loaded. Intraarterial perfusion of prostaglandin E2 restored their ability to release or secrete NF. It is concluded that the release or the synthesis of NF is only possible in the presence of prostaglandins. Its action is not influenced by prostaglandin inhibition or deficiency.

Intra-arterial chemotherapy of the liver with transient, repeated hypoxia.

Intra-arterial liver perfusion with transient repeated hypoxia via an indwelling double-lumen polyurethane catheter was undertaken in 25 of 33 patients with diffuse metastases involving 50%-70% of the liver, and whose primary cancer had previously been treated by local radical resections. Treatment continued over 3-12 months until disease progression and over 3-24 months until thrombosis. In 24 patients with colorectal carcinoma the 1-year survival rate (using the actuarial method) was 79% +/- 17%. The treatment morbidity was low. It is concluded that this form of treatment improves the quality of life and gives safe and effective palliation to the patients.

Pharmacological and hemodynamic studies on flunarizine

Systemic administration of flunarizine (3 mg/kg i.v.) to rats decreased the vascular reactivity of their mesenteries to phenylephrine (PhE) and norepinephrine (NE). Intra-arterial perfusion of flunarizine (100 pg to 1 μg/ml) produced dose dependent attenuation of the vasoconstrictor responses induced by PhE and Ne in the isolated perfused rat mesentery. Flunarizine (5 mg/kg i.p.) did not significantly affect general hemodynamics (i.e. mean blood pressure, heart rate, cardiac output and hematocrits) in anaesthetized rats. However, it produced significant decreases in the blood flows to the kidneys and the spleen associated with similar changes in the percentage distribution of the cardiac output to these organs. These studies indicate that in rats, flunarizine produced preferential effects in different vascular beds.

Modulatory effects of substance P on norepinephrine induced vasoconstrictor responses in the rat mesentery

1. 1. The role of substance P (SP) in adrenergic transmission has been studied in the isolated perfused rat mesentery. 2. 2. Intra-arterial perfusion of SP (4 × 10 −9 to 4 × 10 −7 M) produced a dose dependent potentiation of norepinephrine (NE) induced vasoconstrictor responses and a shift of the log dose-response curve to the left. 3. 3. Saralasin, a specific antagonist of angiotensin II (ang. II) when perfused at a concentration of 3 × 10 −9 M did not change the NE responses as such. However, the potentiating effect of SP could not be demonstrated in the presence of saralasin. 4. 4. Indomethacin, a prostaglandin (PG) synthetase inhibitor, when perfused at a concentration of 2.8 × 10 −6 M, markedly attenuated the vascular responses to NE, which could not be normalized by the addition of SP. 5. 5. It appears that SP's potentiating effect on NE responses in the perfused rat mesentery simulates ang. II and not prostaglandins. A direct non-specific post synaptic sensitizing effect of SP on vascular smooth muscle cell, for its potentiating property, cannot be ruled out.

Intra-arterial perfusion therapy with 5-fluorouracil in patients with metastatic colorectal carcinoma and intractable pelvic pain.

In a phase-II trial, 18 patients with intractable pelvic and perineal pain caused by local recurrent and/or metastatic colorectal carcinoma resistant to combinations of analgesics, systemic cytostatic chemotherapy and/or radiation were treated with intra-arterial perfusion therapy using 15-30 mg 5-FU/kg body wt./day for 1-5 days. Of 18 patients, ten achieved complete pain relief for 3-32 weeks (mean, 15.7 weeks); after the perfusion therapy eight used less than 50% of the amount of analgesics required before treatment; one patient had only a minor response; two patients were treated unsuccessfully. Side effects were mild and controllable. One patient died subsequent to arterial embolism in the leg where the catheter was placed; pelvic perfusion therefore appears risky in patients with severe arteriosclerosis.

Preservation of the rat blood--testis barrier after ligation of the ductuli efferentes, as demonstrated by intra-arterial perfusion with peroxidase

Preservation of the rat blood--testis barrier after ligation of the ductuli efferentes, as demonstrated by intra-arterial perfusion with peroxidase

A new method of treatment of the hydrofluoric acid burns of the extremities

Based on animal experiments we describe a method of treating H.F. burns of the hand by intraarterial perfusion with calcium gluconate as close to the lesion as possible. We prefer this to intraarterial injection as advised by others because we have treated a series of 13 consecutive cases and know of many others in other hospitals with always yielding good results. We therefore advice the use of this therapy for H.F. burns as the best method available at present.

Microcirculatory obstruction in focal cerebral ischemia: albumin and erythrocyte transit.

The objectives were to study plasma and erythrocyte flow in an area of acute focal cerebral ischemia and define their relationship to developing microcirculatory obstruction as determined by morphological techniques. Eighteen adult cats, anesthetized with ketamine hydrochloride, had right middle cerebral artery (MCA) occlusion. Plasma flow was determined by measuring the transit of Iodine-131 (131I) albumin and erythrocyte flow was determined by measuring the transit of Technetium-99 (99Tc) labeled erythrocytes in the right Sylvian region. Transit studies were performed before and immediately after right MCA occlusion and at the end of the ischemic period, 1 hour, 3 hours, or 6 hours after occlusion. Intra-arterial perfusion with a buffered formaldehyde - colloidal carbon solution was carried out after completion of the isotope studies. Swelling of cerebral tissue and impaired carbon filling in the right MCA territory were seen initially after 3 hours occlusion and were more severe after 6 hours occlusion. Ischemic neuronal alterations, edema formation, and capillary luminal narrowing increased with longer periods of occlusion. 131I albumin transit time in the right Sylvian region was 8 +/- 2 seconds before occlusion and 10 +/- 2 seconds immediately after occlusion. 99Tc erythrocyte transit time was 10 +/- 2 seconds before occlusion and 12 +/- 3 seconds immediately after occlusion. 99Tc erythrocyte transit time was 10 +/- 2 seconds before occlusion and 12 +/- 3 seconds immediately after occlusion. Transit times increased progressively with longer periods of occlusion in cats developing cortical ischemic changes. No evidence of complete microcirculatory obstruction to albumin and erythrocyte transit was seen in cats with 6 hours of occlusion despite the impaired filling of the cortical microcirculation with carbon. There were no findings to substantiate the hypothesis that plasmapheresis develops during the early phases of cerebral infarction.

Subacute reactions to intrathecal amipaque (metrizamide), conray and dimer X: a structural and ultrastructural study.

Adult New Zealand rabbits were injected intrathecally with 200 or 300 mgI/ml of metrizamide, meglumine iocarmate or meglumine iothalamate. They were placed in the Trendelenburg position for 20 min and allowed to survive for 1, 2 or 3 weeks. Sacrifice was by intraarterial perfusion of aldehydes under anesthesia followed by preparation of brain and major venous sinuses for light and electron microscopy. Major findings were subpial edema and inflammatory reaction of superficial brain, leptomeninges, subarachnoid space and arachnoid granulations. They were most severe after iothalamate and milder after metrizamide. The severity decreased with time. It is of significance that severe reactions occurred after 300 mgI/ml concentration of metrizamide.

Temporal bone morphology after systemic arterial perfusion or intralabyrinthine in situ immersion—I. Hair cells of the vestibular organs and the cochlea

Abstract The morphological preservation of hair cells of the inner ear was analysed following fixation with intra-arterial perfusion or local intralabyrinthine in situ immersion using six different fixatives of glutaraldehyde (441–876mosm/kg), three fixatives with combinations of glutaraldehyde/paraformaldehyde (917–1196mosm/kg) and 1% osmic tetroxide (346mosm/kg). The influence of added macromolecules such as dextran to the buffer solution was investigated with regard to fixation technique and type of fixative. The best results were obtained when using a direct (local) immersion of the labyrinth with 1% osmic tetroxide. Vascular perfusion is not recommended, independent of type of fixative used. Cochlear outer hair cells and vestibular hair cells type I are more vulnerable to alterations of osmolality and fixation technique than are inner hair cells and hair cells type II.