SEARCH · Search PubMed

Results for “PERFUSION”

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.

SourceResearch connectionFrom yearThrough year

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

At least 307 records · Page 17Linked to original sources

PubMed1993

High-frequency perfusion fluorometry (HFPF): preliminary results on a new technique for assessing bronchial mucosa blood perfusion.

A new method for estimating airway mucosa blood perfusion is proposed. It is based on the use of a high-sensitivity perfusion fluorometer, which allows us to detect the first intravascular passage of injected fluorochromes. Total measuring time can be sensibly reduced with respect to standard perfusion fluorometry, allowing us to make assessments during fiberoptic bronchoscopy. In vitro studies were performed to set up the optical arrangement of the instrument. The optimal measuring distance (2.2 mm) between the probe tip and the fluorescent mucosa was established using a fluorescent film surface to simulate fluorescent mucosa. The depth of tissue layers involved in the fluorescence emission was assessed by positioning tissue sections of different thickness between the probe tip and the fluorescent film. Tissue layers at depths not exceeding 1200 microns were found to contribute to the fluorescence signal recorded by the instrument. Mucosa blood perfusion was evaluated in rat trachea, as a model, under three different experimental conditions of vascularization: (a) basal condition (BC), (b) partial devascularization (PD), (c) full devascularization (FD). Sodium fluorescein (diffusible into the interstice) and fluorescein isothiocyanate-dextran (not diffusible into the interstice) were used as fluorescent tracers. Under the BC both substances allowed us to detect the first passage of fluorochrome through the mucosa capillary network with the same accuracy. In PD the first pass peak disappeared; total emitted fluorescence decreased as well. In FD a flat tracing was recorded. Consistent results were obtained with both substances.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

Studies on the morphology of the isolated perfused rabbit ovary. I. Effect of long-term perfusion.

Isolated ovaries from untreated, sexually mature rabbits were introduced into an in vitro perfusion system and perfused with a chemically defined medium containing albumin. The ovaries were perfused for up to 15 h (mean 11.5 h) and then processed for morphological investigation. Both at the light- and electron-microscopical levels, most of the ovaries exhibited a normal structure comparable with ovaries in situ. In two cases, however, marked accumulations of bacteria were found, although not inside the follicles. Since ovulation in the rabbit normally occurs between 9.5-13 h after mating or human chorionic gonadotrophin treatment, this model seems adequate for studies of ovulation in vitro. It is, however, important to study the ovaries microscopically after the perfusion to detect artifacts, e.g., bacterial infection, that may have influence on the process of ovulation.

Animals↗

PubMed1995

Continuous intraoperative external monitoring of perfusate leak using iodine-131 human serum albumin during isolated perfusion of the liver and limbs.

Regional isolated perfusion using tumor necrosis factor (TNF) shows significant promise for treatment of cancer which is limited to limbs or organs. The high toxicity of TNF requires very sensitive real time monitoring of leakage in order to avoid serious patient complications. Human serum albumin labeled with iodine-131 is used with an externally mounted and collimated NaI(Tl) detector to track the leakage of blood from the isolated perfusion blood circuit into the general systemic vascular space. Blood activity levels measured using the monitor demonstrated a very good correlation with blood serum samples taken concurrently with external monitoring. External monitoring can reduce the risks of perfusion leakage intraoperatively with the precision necessary to safely perform isolated perfusion using TNF.

Chemotherapy, Cancer, Regional Perfusion↗

PubMed1990

Residence time distributions of solutes in the perfused rat liver using a dispersion model of hepatic elimination: 1. Effect of changes in perfusate flow and albumin concentration on sucrose and taurocholate.

The residence time distributions of sucrose and taurocholate have been determined from the outflow concentration-time profiles after bolus input into an in situ perfused rat liver preparation. The normalized variance (and the dispersion number) appeared to be independent of perfusate flow rate (10 to 37 ml/min) and perfusate albumin concentration (0.5%). The apparent volume of distribution for sucrose appeared to increase with flow rate but was unaffected by the concentration of albumin (0-5%) present in the perfusate. The changes in taurocholate availability with flow rate were adequately accounted for by the dispersion model, whereas taurocholate availability-protein binding changes required an albumin-mediated transport model to be used in conjunction with the dispersion model.

Albumins↗

PubMed1996

Normothermic renal artery perfusion: a comparison of perfusates.

Hypothermia and preservative perfusates have been used to decrease ischemic renal injury. This study was performed to identify the preservative function of perfusates independent of the effects of hypothermia. Rats underwent 45 minutes of renal ischemia. Rectal and renal parenchyma temperatures were monitored and maintained within 1 degree C of normal. Perfusates were University of Wisconsin solution (UW), Euro-Collins solution, normal saline solution, and Ringer's lactate solution. A nonperfused ischemic control and a nonischemic control group were also evaluated. Parameters evaluated included serum creatinine and blood urea nitrogen levels, renal ischemic injury grade, renal weight, and gross appearance of the injured kidney. Rats treated with UW solution were found to have a significantly lower creatinine, blood urea nitrogen, and injury grade than the other three perfused groups. The external gross appearance of the UW-treated kidneys was normal, whereas that of the other groups demonstrated moderate to severe injury. Although the mean right/left renal weight difference of the UW-treated group was lower than that of the other three groups, this was not statistically significant. Under normothermic conditions in rats, UW solution affords significant renal protection from ischemia. Euro-Collins, normal saline, and Ringer's lactate solutions display no significant protective effect.

Adenosine↗

PubMed1982

Effect of changes in perfusion pressure on the position of the electrophysiologic border zone in acute regional ischemia in isolated perfused dog and pig hearts.

In isolated, Langendorff perfused hearts, 60 direct-current extracellular electrograms were simultaneously recorded from the left ventricular epicardium. In each experiment, the left circumflex branch and the left anterior descending coronary artery were successively occluded for 15 minutes, each occlusion separated by a long reperfusion period. During the occlusion, perfusion pressure to the nonoccluded arteries was changed from a high to a low value and vice versa, and the position of the electrophysiologic border (the zone where T-Q segment potentials became negative) was determined. In some experiments tissue biopsy samples were taken from recording sites and analyzed for lactate and creatine phosphate. In all experiments the metabolic border correlated well with the electrophysiologic border. In other experiments, the coronary arteries were injected with barium sulfate; epicardial collateral channels were found in dogs hearts, but not in pig hearts. In seven of eight dog hearts, the border could be shifted by changing perfusion pressure; in seven of eight collateral channels, changes in perfusion pressure could enlarge or reduce the area showing ischemic changes. Despite species differences, not all hearts within one species behaved the same: One pig heart behaved as a dog heart, one dog heart as a pig heart.

Animals↗

PubMed1980

Isolated testes perfusion: a method using a cell- and protein-free perfusate useful for the evaluation of potential drug and/or metabolic injury.

A method is described by which the testes and left kidney of the rat can be isolated, maintained, and selectively perfused in vitro to examine the effect of potential gonadal toxins. The integrity of the system was confirmed by demonstrating appropriate increases in steroid (testosterone and estradiol) production and secretion in response to stimulation with chorionic gonadotropin; maintenance of testicular ATP levels; and failure to observe an increase in perfusate concentration of transaminase and lactic dehydrogenase over 2 hr of perfusion. After such confirmation, the effect of two potential gonadal toxins, ethanol and acetaldehyde, at levels commonly found in the plasma of men who abuse alcohol, was evaluated using the system. Both of these substances significantly (p less than 0.01) reduced the testosterone production and secretory response of the isolated perfused testes. The advantages of such a system are that the effect of specific potential toxins independent of hepatic metabolism and/or hypothalamic-pituitary suppression by such substances can be identified and examined in a system free of extragonadal metabolism.

Acetaldehyde↗

PubMed2006

Aortic arch surgery: thoracoabdominal perfusion during antegrade cerebral perfusion may reduce postoperative morbidity.

BACKGROUND: This study aimed to assess the results of the introduction of thoracoabdominal perfusion (TAP) in the surgical strategy for aortic arch replacement with cerebral protection. METHODS: Two hundred two arch procedures performed with moderate hypothermia (22 degrees to 26 degrees C) and antegrade cerebral perfusion (ACP) were the objects of retrospective investigation. Acute type A dissection was the indication in 164 patients, aortic aneurysm in 38. In 80 patients, during ACP, the thoracoabdominal aorta was perfused either in an antegrade fashion through proximal descending aorta endoluminal cannulation (in 62 dissections), or retrograde through femoral artery cannulation with proximal descending aorta endoluminal occlusion (in 18 aneurysms). Hospital mortality and morbidity rates were compared between the two treatments (group A: ACP only, 122 patients; group B: ACP plus TAP, 80 patients) and the underlying aortic disease (dissection/aneurysm) was stratified. RESULTS: Cerebral perfusion (p = 0.008) and cardiopulmonary bypass times (p = 0.035) were significantly longer in group B. No complication related to the TAP technique was observed in group B. Overall hospital mortality was 12.9%, without significant difference between groups. No differences were found in terms of permanent neurological dysfunction between groups A (9.3%) and B (9.1%; p = 0.58). Group B patients showed lower rates of respiratory failure (18.2% versus 30.5% in group A; p = 0.038), shorter mechanical ventilation times (18.1 +/- 26 hours versus 57.9 +/- 70.1; p < 0.001) and lower incidence of acute renal failure (6.5% versus 18.6%; p = 0.012). Shorter intensive care and hospital stays were observed in group B (p = 0.02). CONCLUSIONS: The adjunction of TAP to ACP was associated with lower rates of end-organ complications, even in more extensive and time-consuming procedures.

Aortic Dissection↗

PubMed1999

Efflux of T4 from the in situ perfused liver of rainbow trout: effect of T4, dithiothreitol and cysteine in the perfusate.

A Cortland saline-perfused rainbow trout (Oncorhynchus mykiss) liver model was used to study aspects of T4 efflux from the intact organ system. There was a consistent efflux of T4 in the absence of T4 in the perfusate, and the T4 efflux was increased in the presence of T4 in the perfusate, but the efflux was not T4-dose dependent. The addition of the thiol-containing compound dithiothreitol (DTT, 2 mM) to the perfusate had no significant effect on the flux of T4 from the liver, whereas the addition of cysteine (2 mM), a thiol-containing amino acid suppressed T4 efflux. The results are consistent with the known mechanisms of thyroid hormone trafficking across cell membranes, and suggest that organ systems, such as the liver, may act as a major reserve of hormone, thus participating in plasma thyroid hormone homeostasis.

Animals↗

PubMed1979

Metabolism of palmitate in perfused rat liver. Effect of low and high ethanol concentrations at various concentrations of palmitate in the perfusion medium.

1. The effect of ethanol on the metabolism of [1-(14)C]palmitate in rat liver was investigated in a single-pass perfusion system at concentrations of 10mm- or 80mm-ethanol and 0.2mm- or 1mm-palmitate. 2. After the perfusion the hepatic lipid was isolated in subcellular fractions. The two major fractions contained triacylglycerol from cytoplasmic lipid droplets and from endoplasmic reticulum plus Golgi apparatus respectively. 3. In experiments with 0.2mm-palmitate perfusion with 10mm- or 80mm-ethanol did not measurably increase the esterification, and the oxidation was markedly decreased and the fatty acid uptake was not affected. 4. Perfusion with ethanol, at 1mm-palmitate, increased the fatty acid uptake, increased esterification and decreased oxidation. The effects of 10mm- and 80mm-ethanol were similar. The incorporation of [1-(14)C]palmitate into triacylglycerol in cytoplasmic lipid droplets was not affected statistically significantly by ethanol. Ethanol increased the incorporation of [1-(14)C]palmitate into di- and tri-acylglycerol in the membranous fraction. Estimated chemically, the contents of di- and tri-acylglycerol were only slightly affected by ethanol. These results suggest that the effect of ethanol was to increase the turnover of fatty acids in triacylglycerol rather than to increase its accumulation. 5. The results indicate that an increased concentration of fatty acids is more important for the formation of acute fatty liver in fed rats than are the direct effects of ethanol on hepatic fatty acid metabolism.

Animals↗

PubMed1979

Acute effects of ethanol on the perfused rat liver. Studies on lipid and carbohydrate metabolism, substrate cycling and perfusate amino acids.

1. Livers from fed rats were perfused in situ with whole rat blood containing glucose labelled uniformly with (14)C and specifically with (3)H at positions 2, 3 or 6. 2. When ethanol was infused at a concentration of 24mumol/ml of blood the rate of utilization was 2.8mumol/min per g of liver. 3. Ethanol infusion raised perfusate glucose concentrations and caused a 2.5-fold increase in hepatic glucose output. 4. Final blood lactate concentrations were decreased in ethanol-infused livers, but the mean uptake of lactate from erythrocyte glycolysis was unaffected. 5. Production of ketone bodies (3-hydroxybutyrate+3-oxobutyrate) and the ratio [3-hydroxybutyrate]/[3-oxobutyrate] were raised by ethanol. 6. Formation of (3)H(2)O from specifically (3)H-labelled glucoses increased in the order [6-(3)H]<[3-(3)H]<[2-(3)H]. Production of (3)H(2)O from [2-(3)H]glucose was significantly greater than that from [3-(3)H]glucose in both control and ethanol-infused livers. Ethanol significantly decreased (3)H(2)O formation from all [(3)H]glucoses. 7. Liver glycogen content was unaffected by ethanol infusion. 8. Production of very-low-density lipoprotein triacylglycerols was inhibited by ethanol and there was a small increase in liver triacylglycerols. Very-low-density-lipoprotein secretion was negatively correlated with the ratio [3-hydroxybutyrate]/[3-oxobutyrate]. Perfusate fatty acid concentrations and molar composition were unaffected by perfusion with ethanol. 9. Ethanol decreased the incorporation of [U-(14)C]glucose into fatty acids and cholesterol. 10. The concentration of total plasma amino acids was unchanged by ethanol, but the concentrations of alanine and glycine were decreased and ([glutamate]+[glutamine]) was raised. 11. It is proposed that the observed effects of ethanol on carbohydrate metabolism are due to an increased conversion of lactate into glucose, possibly by inhibition of pyruvate dehydrogenase. The increase in gluconeogenesis is accompanied by diminished substrate cycling at glucose-glucose 6-phosphate and at fructose 6-phosphate-fructose 1,6-bisphosphate.

Amino Acids↗

PubMed1980

Oxygen consumption in perfused skeletal muscle. Effect of perfusion with aged, fresh and aged-rejuvenated erythrocytes on oxygen consumption, tissue metabolites and inhibition of glucose utilization by acetoacetate.

1. O2 consumption, glucose metabolism and the energy status of skeletal muscle were compared in isolated rat hindquarters perfused with aged (21--35 days), fresh and aged-rejuvenated human erythrocytes. 2. The age of the erythrocytes did not affect O2 consumption, glucose utilization or lactate release either at rest or during exercise. The concentrations of ATP, phosphocreatine and lactate within the muscle were also unaffected by the use of aged erythrocytes. 3. Perfusion with acetoacetate did not inhibit glucose utilization; but, it caused a marked increase in the tissue concentration of citrate in the soleus, a slow-twitch red muscle, and a smaller increase in the gastrocnemius, which contains fast-twitch red and white fibres. Results were similar in hindquarters perfused with aged and aged-rejuvenated erythrocytes. 4. These findings suggest that perfusion with aged human erythrocytes does not cause major alterations in the metabolic performance of the isolated rat hindquarter.

Acetoacetates↗

PubMed1987

Metabolism of benzo[a]pyrene in the perfused rat liver: factors affecting the release of phenolic metabolites into the bile and perfusate.

The metabolism of benzo[a]pyrene (BP) to phenolic metabolites was studied in the non-recirculating perfused rat liver. After 30 min of BP (20 microM) infusion most phenols formed (78%) remained in the liver. Phenols detected in the perfusate and bile were primarily glucuronide (70%) and sulfate (20%) conjugates. When albumin was present in the perfusion buffer, release of phenols into perfusate was the predominant route of elimination from the liver. In the absence of albumin, biliary efflux of phenols predominated. Biliary concentrations of BP phenolic glucuronides and sulfates were at least 3.5-fold higher than their hepatic concentrations, suggesting an active transport of these metabolites into bile. Rates of biliary elimination of BP phenols were enhanced by the infusion of taurocholate, which displaces BP metabolites from intracellular stores. These results confirm and extend previous studies which have demonstrated that the release of BP phenols from the liver is a complex process, influenced by the availability of intracellular storage sites, biliary excretion mechanisms and the presence of carrier proteins such as albumin.

Animals↗

PubMed1989

Zones of increased perfusion (hot spots) on perfusion lung scans: correlation with pulmonary arteriograms.

Perfusion lung scans are occasionally characterized by focal zones of apparent hyperperfusion ("hot spots"). To investigate the frequency and significance of this phenomenon, ventilation-perfusion lung scans and pulmonary arteriograms were reviewed in 72 patients who underwent both procedures for the evaluation of suspected pulmonary embolism. Hot spots were present in the scans of 13 patients and usually occupied less than one pulmonary segment. Most hot spots were detected within a region of atelectasis identified on chest radiographs (38%). A substantial number of the remaining hot spots were located in the lung adjacent to regions of embolus. In patients with massive embolus, hot spots actually represented normally preserved perfusion in the presence of globally reduced perfusion elsewhere.

Adult↗

PubMed1976

Preservation of dog kidneys by hypothermic perfusion with glucose-free and glucose-rich perfusates.

Dog kidneys were perfused for 48 h at 8-10 degrees C with two different perfusion fluids: one fluid rich in glucose, and another in which mannitol was a substitute for glucose. Immediately after reimplantation of the perfused kidneys, contralateral nephrectomy was performed. Kidney function, estimated by serum creatinine, was the same in both groups of animals, and 2 weeks after implantation it was identical to that of dogs with a single normal kidney. In a second series of experiments the renal utilization of glucose and glycogen was studied. Although small amounts of perfusate glucose were metabolized to lactate and CO2, the results of this study indicate that the kidney is not dependent upon glucose for its metabolic needs in order to retain function during 48 h hypothermic preservation.

Animals↗

PubMed1996

Consideration on moments of outflow profile in liver perfusion system with change in perfusate flow rate using oxacillin as model drug.

The effect of perfusate flow rate on hepatic structure and hepatic uptake kinetics was investigated using oxacillin as a model drug and bovine serum albumin (BSA) as a reference substance in the liver perfusion system from the standpoint of a dispersion model and moment characteristics. The estimated recovery ratio (FH) of oxacillin was about 40% which was independent of the change in perfusate flow rate. The mean transit time (tH) of oxacillin decreased with an increase in flow rate, while the relative variance (sigma 2/t2H) of oxacillin was independent of the flow rate. The tH of BSA decreased with an increase in the flow rate to the same extent as that of oxacillin, while sigma 2/t2H of BSA was independent of flow rate. When the dispersion model is adopted as a model system to analyze hepatic perfusion data following the pulse input, the moment characteristics (FH, tH and sigma 2/t2H) are given in complicated equations. It is demonstrated by the present investigation that these moment equations can be extensively simplified for a drug with a medium extraction ratio (FH > 50%), i.e., FH is independent of the distribution, both FH and tH are independent of the dispersion process in the hepatic blood space, and both tH and sigma 2/t2H are independent of the elimination. Thus, it is shown that FH and tH are exactly the indices of elimination and distribution, respectively, and sigma 2/t2H is the index of dispersion in the blood space plus nonequilibrium in the hepatic distribution.

Animals↗

PubMed1992

[Comparison of bidirectional collagenase perfusion with one way perfusion in the isolation of periportal or perivenous hepatocytes in rats].

To selectively isolate hepatocytes from the periportal (PP) and perivenous (PV) regions of rat liver acinus, we compared two different perfusion methods with collagenase: the bidirectional perfusion method (2-P) and the one way perfusion method (1-P). We determined the optimal conditions for each method on the basis of the zonal selectivity of isolated hepatocytes with a hematoxylin-eosin stained liver specimen. By both methods, hepatocytes were selectively isolated from the PP and PV regions. Comparing cell yield and cell viability after the two perfusion methods, 1-P was found to be better than 2-P. Density gradient centrifugation with Percoll was found to be an effective procedure for removing the damaged hepatocytes. We concluded that 1-P could isolate viable PP and PV hepatocytes with a normal glucagon-cyclic AMP response and ultrafine structure in high yield from rat liver.

Animals↗

PubMed1986

Effects of stimulation on steroid output and perfusion medium flow rate in the isolated perfused rat adrenal gland in situ.

Using the in-situ, isolated, perfused rat adrenal system, the actions of adrenal stimulants on steroidogenesis and perfusion medium flow rates (under constant perfusion pump conditions) have been studied. In a series of 100 experiments, initial rates of corticosterone output and flow rates were found to be positively correlated, although there was no such relationship between initial rates of aldosterone output and flow rates. Furthermore, in stable perfusion conditions, bolus injections of ACTH increased both flow rate and steroid output in a dose-related manner. In individual experiments there was a clear correlation between corticosterone and flow, but the association between aldosterone secretion rate and flow was less evident. It is possible that this discrepancy arises because of temporal differences in the responses of these two steroids. Flow was also stimulated by dibutyryl cyclic AMP (dbcAMP), with correlations with steroid output similar to ACTH, but the specific zona glomerulosa stimulants angiotensin II amide and potassium ions had, if anything, inhibitory effects on flow, but only at high concentrations. The data suggest that ACTH and dbcAMP evoke specific responses in the adrenal vasculature, resulting in relatively decreased intraglandular vascular resistance. They furthermore suggest that the secretory functions of the inner adrenocortical zones are subject to the additional control of vascular elements in the intact gland.

Adrenal Glands↗