A comparison of absorption of glycerol tristearate and glycerol trioleate by rat small intestine

Generally, fats rich in saturated fatty acids raise serum cholesterol, whereas fats rich in polyunsaturated fatty acids lower it. There appear to be exceptions; e.g., stearic acid (18:0)-rich fats have little or no effect on serum cholesterol concentrations. This apparent lack of cholesterolemic effect of stearic acid-rich fat could be because intestinal absorption of fat is poor or subsequent plasma and/or tissue metabolism of fat is different. To investigate mechanisms involved, we compared intestinal digestion, uptake, and lymphatic transport of glycerol tristearate (TS) and glycerol trioleate (TO, 18:1). Two groups of rats bearing intestinal lymph fistulas were used. TO rats were fed intraduodenally for 8 h at a constant rate a lipid emulsion of 25 mumols/h of TO (labeled with glycerol tri[9,10 (n)-3H]oleate), 7.8 mumols of egg phosphatidylcholine, and 57 mumols of sodium taurocholate in 3 ml of phosphate-buffered saline. TS rats were fed the same lipid emulsion except that TS replaced TO and the emulsion was labeled with glyceryl [1,3-14C]tristearate. The lymph triglyceride and radioactivity were determined. After infusion, the luminal and mucosal radioactive lipid content was analyzed. The results showed that there was significantly less lipid transported in the lymph of TS rats compared with TO rats. The results also showed a significant decrease in the absorption of TS as compared with TO. This was due in part to poor lipolysis. In addition, the lipid absorbed by the intestine of the TS rats was transported into lymph less efficiently than in TO rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Temocillin: lymph penetration and protein binding

Temocillin, a novel betalactam antibiotic, was administered in doses of 1,2 and 4 g i.v. to 12 healthy subjects and the plasma concentrations of free and protein bound temocillin assayed and protein binding parameters were calculated. In a second study 2 g of temocillin was administered i.v. to 12 healthy subjects and samples of lymph were collected and assayed for total temocillin. Using the protein binding parameters so obtained the corresponding free temocillin in lymph was calculated. The clinical significance of the lymph penetration is discussed.

[Status of lymphatic vessels, lymph flow and lymph toxicity in patients with obliterating arterial diseases of the lower extremities]

The condition of the lymph vessels, the lymph flow, and the toxicity of peripheral lymph were studied in 46 patients with obliterating diseases of the arteries of the lower limbs. The results of the study showed the severity of the destructive changes in the peripheral lymphatic system to be directly dependent on the severity of the arterial ischemia of the limb. Block of the lymphatic system, deceleration of the lymph flow, and changes in the lymph vessels themselves lead to deterioration of the tissue drainage function and intensification of regional endotoxicosis. In view of which correction of the peripheral lymphatic system should be included in the complex of measures for the treatment of patients with obliterating diseases of the lower limb arteries.

Pressure within the thoracic duct modulates lymph composition

The amount of lymph received by the thoracic duct depends on each contributing organ's ability to produce interstitial fluid and generate a pressure differential moving lymph into the central lymphatic circulation. It has been reported that varying the pressure within the thoracic duct could alter each organ's contribution to thoracic duct flow. The thoracic duct above the diaphragm was cannulated to obtain lymph from the liver, gut, and lower body. Pressure within the thoracic duct was elevated serially by increasing the lymphatic cannula outflow height. This caused lymph protein concentration to increase while chyle concentration (measured by absorbance) decreased. The data demonstrate that as thoracic duct pressure increases, the percentage contribution of gut lymph flow (as represented by chyle concentration) decreases while the contribution of lymph originating within the liver (as indicated by higher protein concentration) increases. We conclude that pressure variation within the central lymphatic system affects the amount of lymph or edema fluid leaving any given organ.

Surface-active phospholipid in muscle lymph and its lubricating and adhesive properties

In order to investigate the role of phospholipid in facilitating lymph flow, "deep-thigh" lymph was collected from ten anesthetized dogs and analyzed for phospholipids using thin-layer chromatography. The lymph was found to be surface active at liquid and at solid surfaces at which it deposited a hydrophobic monolayer in vitro. Extracted phospholipid was found to be an effective release agent as a monolayer, reducing the force of adhesion of 5% protein solutions by 76% according to a standard test for tacky glues. The same monolayers were effective lubricants, reducing friction by 96%; while mixtures of the same phospholipids from synthetic sources gave similar results for release and lubrication. Surfaces in contact with extracellular fluid or lymph in vivo were found to be hydrophobic with a drop of saline on semitendinosus muscle fibers displaying a contact angle of 40.2 degrees +/- 7.2 degrees. The results are considered compatible with the hypothesis that surface-active phospholipid facilitates the flow of lymph; while it could also provide boundary lubrication for sliding of connective tissue in locomotion and for any relative movement of motor units in muscle contraction and fatigue.

Recovery of fish oil-derived fatty acids in lymph of thoracic duct-cannulated Wistar rats

The absorption of equivalent doses of eicosapentaenoic and docosahexaenoic acids was compared in rats when administered as the ethyl ester concentrate, ethyl ester concentrate plus olive oil, free fatty acid or triacylglycerol (menhaden oil). Lymph was collected from a thoracic duct cannula for 24 hr after dosing via an indwelling duodenal catheter. After 24 hr, the absorption of eicosapentaenoic acid was greater for the free fatty acid and menhaden oil than for the ethyl ester form, but docosahexaenoic acid absorption was comparable for all forms. Other rats had greater plasma levels of eicosapentaenoic and docosahexaenoic acids 5 hr after oral gavage dosing with menhaden oil than did rats dosed with the ethyl ester form.

[Fibronectin from the lymph of healthy persons]

Content of fibronectin was studied in lymph and blood plasma of 24 healthy 23-57 years old men. Concentration of fibronectin in lymph and blood plasma was 44.2 +/- 21.7 mg/ml and 354 +/- 88 mg/ml, respectively. Interrelations were not found between content of fibronectin in lymph and blood plasma as well as between the total content of protein and fibronectin in lymph. Fibronectin in lymph was shown to occur in its intact form using immunoblotting procedure involving monoclonal antibodies to fibronectin. Simultaneously with whole molecules of fibronectin its fragments appear to be present in lymph.

Lung vascular permeability changes in lambs with hyaline membrane disease

To investigate the mechanism of pulmonary edema in hyaline membrane disease (HMD), lymph from the efferent duct of the mediastinal lymph node was collected in premature lambs before and after delivery by cesarean section. Mean lymph flow in 7 lambs with histologically verified HMD increased progressively over 4 h after delivery to 3 times the fetal value, while lymph flow in 7 lambs without HMD increased to 3.5 times at 1 h and decreased thereafter. At 4 h after birth, lung lymph flow was significantly higher in lambs with HMD than in lambs without HMD (0.70 +/- 0.15 (SEM) vs 0.43 +/- 0.07 ml.h-1.kg-1). Lymph/plasma concentration ratio for small endogenous protein fractions (effective molecular radius, 3.6 and 3.8 nm) was significantly higher in lambs with HMD than in lambs without HMD at 2-4 h. Postmortem extravascular lung water was significantly higher in lambs with HMD (6.1 +/- 0.5 vs 4.3 +/- 0.3 ml/g dry lung weight). It is concluded that lung water is high in lambs with HMD, which appears to be a result both of delayed absorption of fetal lung liquid and increased permeability of the pulmonary exchange vessels.

Contractility of human leg lymphatics during exercise before and after indomethacin

Subcutaneous lymphatics in the lower leg were catheterized in the retrograde direction in 6 healthy male subjects. The catheter was connected to a pressure transducer, and pressure was measured during three stages of exercise including standing, tip-toeing, and running in place. Before the third stage, indomethacin (50mg) was given i.v. Rhythmic pressure waves were registered in each subject. During the second stage, when the subjects were "warmed up," the frequency (min-1) was 2.4 +/- 0.5 (mean +/- SEM). The corresponding values during tip-toeing and running were 5.8 +/- 0.7 (p less than 0.05) and 5.4 +/- 0.5 (p less than 0.05), respectively. The amplitudes (mean values between 3.2-4.7mmHg while standing) were not consistently altered during tip-toeing or running in any of the three stages. During standing there was a negative correlation between frequency and amplitude. No such correlation was found during tip-toeing or running, or after injection of indomethacin. Indomethacin did not significantly alter any of the measured parameters, but in two subjects the frequencies and amplitudes were decreased (about 50%) during standing, tip-toeing, and running.

The concentration of apolipoprotein A-II in human peripheral lymph

The concentration of apolipoprotein A-I (apoA-I) and of apolipoprotein A-II (apoA-II) was determined immunoelectrophoretically in lymph and plasma of six subjects. The concentration in lymph of apoA-I was 20.3 +/- 3.1 mg/dl, that of apoA-II was 4.6 +/- 0.5 mg/dl. The ratio of the concentration in lymph over that in plasma (CL/CP) for apoA-I was 0.14 +/- 0.1, that for apoA-II 0.14 +/- 0.01. Lymph and plasma samples from two subjects were fractionated by exclusion chromatography and the concentration of both apolipoproteins in resulting fractions was determined immunoelectrophoretically. ApoA-I of lymph eluted with fractions spanning a wider range of particle sizes than plasma apoA-I, while lymph apoA-II eluted predominantly with fractions that contained particles corresponding in size to plasma apoA-II-containing particles. It appears that the largest and smallest lymph HDL represent subspecies of Lp(A-I without A-II). These findings are discussed in the context of their possible bearing on initial stages of reverse transport of cholesterol.

A rapid method for staining large chylomicrons

In this report, we present a rapid method for producing high-quality micrographs suitable for determining the size distributions of particles in concentrated samples of postprandial chylomicrons and chylomicron remnants. The procedure consists of mixing particles with osmium tetroxide in water to stabilize the lipids of the particles. These fixed and positively stained particles are then negatively stained with phosphotungstate in the presence of dilute sucrose. This dual staining procedure prevents the fusion and clustering of chylomicrons during processing for electron microscopy and is effective with particles of different lipid compositions. In addition, this procedure is simple and rapid, adding only one mixing step and 5 min to the preparation time required for conventional negative stains.

Fibronectin fragments in lung lymph after thrombin-induced lung vascular injury

Fibronectin is an adhesive glycoprotein found in plasma and lymph as well as between lung endothelial cells and their collagenous basement membranes. Fibronectin is highly sensitive to proteolytic cleavage. We determined if fragments of fibronectin appear in lung lymph in association with increased lung protein clearance after thrombin-induced intravascular coagulation. Thrombin was infused intravenously, (80 units/kg for 30 minutes) into sheep (n = 8) surgically prepared with chronic lung lymph fistulas. Plasma and lymph fibronectin was assayed by electroimmunoassay. Fibronectin fragments were detected using Western blot analysis. After thrombin infusion, lymph flow increased 650% above baseline within 1-2 hours in association with a 35% decline in lymph-to-plasma total protein concentration ratio. This was followed by a second phase (3.5-6 hours) of normalized lymph-to-plasma ratios coupled with sustained elevation of lymph flow. Lung protein clearance remained elevated (p less than 0.10) for 5.5 hours. Plasma fibronectin levels declined slightly over 1-5 hours (zero time = 597 +/- 64 micrograms/ml; 1.5 hours = 478 +/- 59 micrograms/ml) and then increased significantly (p less than 0.05) over 24-48 hours (760 +/- 85 micrograms/ml). The amount of low molecular weight fibronectin fragments in lung lymph increased over the 1.5-6 hours post-thrombin and then declined over 12-48 hours. Thus after thrombin infusion, fragments of fibronectin were usually detected in increased amounts of lung lymph in association with an elevation of lung protein clearance.

Pulmonary deposition and clearance of aerosolized alpha-1-proteinase inhibitor administered to dogs and to sheep

Augmentation of lung antiprotease levels may be an important therapeutic intervention in the prevention of pulmonary emphysema. We have administered aerosols of plasma-derived human alpha 1 proteinase inhibitor (A1PI) to the lungs of dogs and sheep to investigate (a) delivery of the protein to the distal air spaces of the lung; (b) maintenance of functional activity of the protein; and (c) flux of the protein across the components of the alveolar-capillary membrane. A1PI (26.4 mg/kg body weight) was administered as an aerosol to anesthetized animals; sheep were prepared for the chronic collection of lung lymph. Immunoperoxidase staining of lung tissue obtained 2 h after administration of A1PI demonstrated the presence of human A1PI on the surface of alveoli and distal bronchioles. Bronchoalveolar lavage fluid recovered at intervals after A1PI administration demonstrated time-dependent elevations of human A1PI levels with augmentation of lavage fluid antielastase activity in proportion to the content of human A1PI. Using radiolabeled A1PI as a tracer, we found that 32% of the aerosol was retained in the animals' lungs. Measurements of the rate of loss of A1PI from the lung and of the rate of appearance of human A1PI in plasma resulted in a calculated permeability of the alveolar-capillary membrane to A1PI of 3.49-6.39 X 10(-10) cm/s. Experiments using instrumented sheep allowed independent calculation of endothelial permeability to A1PI of 122-236 X 10(-10) cm/s and calculation of epithelial permeability of 4.70-4.81 X 10(-10) cm/s. Modeling of aerosol delivery of A1PI to humans using the results of these studies predicts that the ratio of plasma/alveolar levels of delivered A1PI will be 0.024, and that aerosolization of 175 mg A1PI/d will result in an A1PI alveolar fluid level of 1.0 mg/ml. Aerosol administration of A1PI may provide an efficient method of augmenting alveolar antiprotease levels.

Interrelated effects of dietary fiber and fat on lymphatic cholesterol and triglyceride absorption in rats

Lymph cannulated rats were administered intragastrically a test emulsion containing 25 mg of [14C]cholesterol, 50 mg of either guar gum, cellulose or chitosan, and 200 mg of either safflower, high-oleic safflower or palm oil, and the absorption of labeled cholesterol and fatty acids was measured. The type of both dietary fiber (P less than 0.001) and fat (P less than 0.05) significantly influenced cholesterol absorption. A significant interaction of fiber and fat on cholesterol absorption (P less than 0.05) was also observed. Chitosan effectively lowered cholesterol absorption more than did guar gum or cellulose, and this effect was more significant when given with safflower or high-oleic safflower oil than with palm oil. When guar gum was the source of dietary fiber, dietary fats did not modify cholesterol absorption. Dietary fiber also significantly affected triglyceride absorption (P less than 0.05). Absorption tended to be low in the chitosan, high in the cellulose and intermediate in the guar gum group. Absorption of safflower and high-oleic safflower oils tended to be higher than that of palm oil when cellulose or guar gum was fed. Guar gum, as compared with the other fibers, altered the absorption pattern of both cholesterol and triglyceride. The results showed that the type of dietary fat significantly influenced the effect that dietary fiber exerted on lipid absorption.

Chylomicron synthesis in experimental nephrotic syndrome

Mesenteric lymph was collected for 48 h from rats with aminonucleoside-induced nephrotic syndrome, receiving an intraduodenal infusion of a triacylglycerol emulsion. In nephrosis, the rates of lymph flow and triacylglycerol transport were approx. 2-fold higher, but the transport of total protein and of apoproteins A-I and E was 2- to 3-fold lower than that in control rats, resulting in chylomicrons with a 3-fold approx. elevated triacylglycerol/protein ratio. Supplementation of the triacylglycerol infusate with glucose and amino acids did not increase the protein or apoA-I and apoE transport. Production or transport of B and C apoproteins in nephrotic rats was also reduced, as indicated by tetramethylurea solubility, incorporation of intraduodenally infused [3H]leucine and staining of the chylomicron proteins on SDS-PAGE gels. Apoprotein A-IV was the only chylomicron component into which the leucine incorporation was elevated, but its relative content was not increased on SDS-PAGE gels. Lymph chylomicrons of nephrotic rats were larger in size (1498 +/- 37 vs. 1235 +/- 23 A), consistent with the higher triacylglycerol/protein ratio. The concentration of all lipoprotein classes was markedly elevated in the plasma of nephrotic rats, as was that of the total A-I and E apoproteins. Intravenous injection of 125I-labelled HDL, followed by tracing of the label in lymph chylomicrons, indicated a lower rate of transfer of HDL apoproteins from plasma to lymph in nephrotic rats. We conclude that the intestinal chylomicron formation in nephrosis is characterised by an enhanced triacylglycerol transport without the appropriate apoprotein complement. This is probably due to the limited capacity of enterocytes, in marked contrast to hepatocytes, to respond to the hypoproteinemia of nephrosis with increased production and/or transport of the apoproteins.

[Lipid metabolism and lymph coagulability in the postresuscitation period]

The values of lipid metabolism and lymph coagulation in the restoration period after resuscitation were studied in experiments on rabbits. A clear correlation between the values was revealed. Increase of concentration of total lipids and of lipid fractions was accompanied by increase of the lymph coagulation potential, which led to disturbed tissue drainage of lymph and was one of the important causes of the development of postresuscitation complications. The elaboration of pathogenetic therapy for regulation of lipid metabolism and lymph coagulation in the postresuscitation period is necessary.

Rat intestinal lymph osmolarity during glucose and oleic acid absorption

The two major purposes of this study were to determine 1) how glucose and oleic acid absorption by the intestinal villi influenced the osmotic composition of lymph as it exited the villus base and 2) what if any changes in lymph osmolarity occurred as the lymph traversed through the bowel wall. The rat jejunum was used in all studies and lymph was collected from individual lymphatics at 0.5-1 nl/min during control states and luminal exposure to 35-550 mg% glucose solutions (isotonic in saline) and 5 and 20 mM oleic acidtaurocholate solutions. Lymph collected from the base of villi during vigorous motility had an osmolarity of 403 +/- 15 mosM at rest and was only increased 30-50 mosM more except during exposure to 550 mg% glucose, where osmolarity increased over 100 mosM. Under comparable conditions, the submucosal lymph osmolarity at rest was 302 +/- 3.5 mosM and increased to 330-350 mosM during exposure to all of the solutions tested. When intestinal motility was virtually stopped, the submucosal lymph osmolarity was isotonic for all solutions tested. These observations indicate that absorption of glucose and oleic acid increased the osmolarity of lymph, leaving the villus only 30-50 mosM unless a glucose concentration of 550 mg% was present. Furthermore, the increased flow of villus lymph during absorption raised the osmolarity of the submucosal lymph when bowel motility assisted the lymph propulsion. This movement of materials from the villus to the submucosa by venular blood and lymph flow provides an opportunity for the villus tissue to influence the composition of the submucosal interstitial environment.

Alternative pathways for drainage of cerebrospinal fluid in the canine brain

Although the brain has no formal lymphatic system, a substantial quantity of cerebrospinal fluid (CSF) has nonetheless been shown to drain via cervical lymphatics. To pursue further the issue of alternative drainage pathways for CSF, we infused a solution of Ringer's lactate (RL) into the cisterna magna of the dog brain and monitored both the flow and concentration of total protein of cervical lymph. This maneuver promoted a nearly three-fold rise in intracranial pressure and was accompanied by a rise in cervical lymph flow and fall in its protein content. In addition, a profuse nasal discharge (11.4 ml/hr) developed with a moderately high protein content of the rhinorrhea fluid (1.8 g/dl), along with similar appearance times of Evans blue dye (instilled in the cisterna magna) in both cervical lymph and the rhinorrhea fluid (48-70 minutes after infusion). These findings suggest alternative drainage pathways for CSF besides the arachnoid villi (Pacchionian bodies) including connections with lymphatics in the neck and along the olfactory nerve, and around the cribiform plate to the nasal submucosa, and with proptosis, perhaps also through the aqueous humor-canal of Schlemm and nasolacrimal duct.

Sampling of lymph from lymph vessels afferent to the supramammary lymph gland in the cow

A technique for catheterization of a lymph vessel afferent to the supramammary lymph gland in the cow is described. The operation was made with the cow under general anaesthesia. The lymph vessel was catheterized with a 30 cm long heparinized polyethylene catheter with an external diameter of 2.5 to 3 mm. Generally at least 5 ml of lymph could be collected within a period of 3 to 5 minutes. In 11 out of 15 cows lymph could be collected for 7 days or longer.

Isoproterenol inhibits the increase in microvascular membrane permeability produced by bradykinin

Bradykinin (BRADY) is hypothesized to cause the "capillary leak" syndrome in patients with sepsis, trauma, and burns. Our purpose was to determine if isoproterenol (ISO) reversed a BRADY-produced accelerated loss of intravascular fluid and protein into the interstitium of skin. An increase in microvascular permeability in canine hind paw skin was sustained by a continuous femoral artery infusion of BRADY (0.2 micrograms/kg/min). After 2 hours of BRADY, skin lymph flow (LYM FLOW microliters/min) increased nine-fold and skin lymph-to-plasma total protein concentration ratio (RTP) was substantially increased. Mean blood flow in the femoral arteries was increased four-fold by the BRADY infusion. After 2 hours of BRADY-induced increased permeability, five of the ten dogs were started on intravenous ISO (2 micrograms/min continuously) which increased heart rate from 182 +/- 15 to 222 +/- 11 beats/min. ISO reversed the increase in RTP produced by the BRADY. After 8 hours of BRADY, there was less tissue albumin in the dogs given ISO (14.5 +/- 2.0 vs. 29.5 +/- 6.6 mg/gram dry wgt, p less than 0.05 unpaired t-test). ISO can reverse the sustained increase in skin microvascular permeability produced by BRADY.

[The blood and lymph electrolyte composition in the postresuscitation period]

The electrolyte composition (Na+, K+, Ca2+, Mg2+) of blood serum and lymph was studied in experiments on 17 mongrel dogs in the postresuscitation period after clinical death. The concentration of these electrolytes reduced in the postresuscitation period. Comparison of data obtained in study of blood and lymph showed the revealed changes to be of one trend. The above-said is evidence of the expediency of including in the complex of postresuscitation therapeutic and preventive measures means for normalizing the electrolyte composition of not only the blood but also the lymph.

The lung inflammatory response to thermal injury: relationship between physiologic and histologic changes

We studied the effect of a body burn on lung physiologic, biochemical, and histologic changes in a 2-day postburn period. A 15% of total-body-surface third-degree burn was produced in 24 adult sheep with lung and burn lymph fistulas. Eight sheep were killed at 12 hours and eight at 48 hours. At 12 hours we noted increased lung tissue lipid peroxidation, lung congestion, and neutrophil sequestration, in addition to a 30% decrease in lung compliance. Lung permeability and water content were not increased. Increased release of lipid peroxides and prostanoids were noted from burn tissue, as evidenced by increased plasma levels of malondialdehyde and conjugated dienes that remained elevated for about 8 hours and were decreased with wound removal. The lung inflammatory response was still present at 48 hours, the cells being primarily neutrophils. Nevertheless, the lipid peroxidation process, as measured by lung tissue malondialdehyde, had resolved. There was no evidence of burn tissue infection, measured by quantitative culture, to explain the persistent increase in lung inflammatory cells. Excision and closure of the burn wound at 3 hours postburn in eight sheep attenuated the lipid peroxidation and compliance changes but did not decrease the neutrophil sequestration. We conclude that burn injury results in a local wound oxidant release that leads to lipid peroxidation, both in wounds and in lung, as well as lung inflammation. The lipid peroxidation process may be attenuated by removal of the wound. The neutrophil sequestration is not altered, however, indicating this response occurs very early after injury, probably as a result of oxidant-initiated complement activation.

Direct radioimmunoassay of active and inactive human glandular kallikrein: some physiological and pathological variabilities

We have developed a sensitive and specific radioimmunoassay which allows the detection of human glandular kallikrein in biologic fluids at a level of 40 pg/ml. The antisera did not recognize human plasma kallikrein and glandular kallikrein from other species including marmoset. Furthermore the antibody did not bind pro-kallikrein but was specific for the trypsin activated kallikrein. The antibody inhibited the kininogenase activity of standard kallikrein incubated with human kininogen. However active kallikrein inhibited by inhibitors bound at the active site is still detectable, indicating that the antibody is specific for the structure of the active form but not for the active site. In normotensive subjects, daily urinary kallikrein excretion increased with age until 30, then a decrease was observed. In renal transplanted recipients a progressive increase of the active form was found. A low concentration of immunoreactive active kallikrein was detected in lymphatic fluids of patients suffering from acute pancreatitis treated by lymphatic drainage; although this kallikrein is the active immunoreactive form, a very weak kininogenase activity was measured, suggesting a partial inhibition by anti-proteases. These data provide complementary evidence for the physiological and pathological role of glandular kallikrein.

Inhibition of thromboxane synthetase accentuates hemodynamic instability and burn edema in the anesthetized sheep model

Thromboxane A2 production is increased early after burn. We studied the effect of inhibiting thromboxane synthetase, using dazmegrel, on postburn hemodynamic stability and edema formation, the latter monitored by burn tissue lymph flow. Dazmegrel (3.4 mg/kg) was given to six anesthetized sheep, and a 40% of total-body-surface third-degree burn was produced. Lactated Ringer's solution was infused at a rate to restore filling pressures during a 12-hour study period. Data were compared to burn alone (n = 8), anesthesia alone (n = 6), and dazmegrel alone (n = 5) groups. The latter two groups showed no physiologic changes. Dazmegrel pretreatment prevented increased thromboxane A2, measured as thromboxane B2, but resulted in a significant increase in plasma prostacyclin, measured as 6-keto-PGF1 alpha. In addition, a marked vasodilatation and decrease in systemic vascular resistance were noted, as well as a 30% increase in fluid requirements and an increase in lymph flow compared with burn alone. The increase in prostacyclin more than likely accentuated the burn-induced permeability change. Of interest was that oxygen consumption was better maintained with dazmegrel postburn, even with the relative hypovolemia, indicating that postburn vasoconstriction impairs adequate O2 delivery to tissues and that thromboxane synthetase inhibition attenuates this process.

Activity and transport of antithrombin during acute limb ischemia

Antithrombin (AT III), a major circulating anticoagulant, may be influenced by ischemia-induced changes in microvascular integrity and contribute to localized hypercoagulability. In a nonheparinized intact canine hindlimb model we determined AT III activity by chromogenic substrate assay (S-2238); coagulation changes with fibrinogen, activated partial thromboplastin time (aPTT), and prothrombin time (PT); and transvascular exchange by lymph-to-plasma total protein concentration ratio. Femoral venous plasma and lymph samples were assayed during 1 hour of steady state (C), 6 or 8 hours of aortoiliac occlusion (I), and 1 or 3 hours of reperfusion (R). Four groups were studied: GI, sham operated (n = 5); GII, moderate ischemia (n = 7), arterial pressure 30% to 45% C, GIII, 6 hours of severe ischemia (n = 7), arterial pressure 5% to 20% C; and GIV, 8 hours of severe ischemia (n = 5), arterial pressure 5% to 20% C. All parameters varied near baseline in the control group and the group with moderate ischemia. Fibrinogen decreased after 3 hours of ischemia in GIII from 218 +/- 38 to 175 +/- 46 mg/dl (mean +/- SEM) and in GIV from 254 +/- 39 to 201 +/- 44 mg/dl (p less than 0.005) as aPTT and PT increased. All parameters returned to baseline on R in GIII only. Plasma AT III decreased in GIV from 89% +/- 4.6% to 53.6% +/- 16.2% (p less than 0.005) after 3 hours and remained low during late I and R.(ABSTRACT TRUNCATED AT 250 WORDS)

The association of Escherichia coli virulence and pulmonary microvascular damage

Bacterial virulence indicates the degree of pathogenicity of a given strain of microbe for a given host. The effect of Escherichia coli virulence on lung microvascular permeability was studied in sheep with chronic pulmonary lymph fistulas following peritoneal contamination. The study was divided into four groups: (1) wild-type E coli (WT group, 2.5 x 10(9) colony-forming units [CFUs]/kg); (2) virulent E coli (PV group, 2.3 x 10(9) CFUs/kg); (3) nonvirulent E coli (PNV group, 2.6 x 10(9) CFUs/kg); (4) high-inoculum wild-type E coli (HIWT group, 6.1 x 10(9) CFUs/kg). In the late period (two to six hours), the increase in lung lymph flow in the PV group was significantly greater than the WT, PNV, and HIWT groups, with no difference noted among groups with respect to the pulmonary artery pressure, pulmonary wedge pressure, or albumin lymph/plasma ratio. It was concluded that (1) increased E coli virulence results in increased lung microvascular damage and (2) increased lung microvascular damage as a function of E coli virulence may not be solely due to increased bacterial numbers as a function of time.

Prompt elevations of PGE2 and thromboxane A2 metabolites in peripheral node efferent lymph of sheep following drainage area immunization

In the past decade, the main interest in the involvement of prostaglandin E2 (PGE2) in the immune response has been concerned with its role in immunomodulation (suppression) both in vitro and in vivo. Comparatively little attention has been devoted to its immunostimulatory role. It has been suggested that PGE2, like histamine, may function as a 'double agent', initially triggering, facilitating and augmenting a stimulatory immune response and later modulating, limiting and contributing to the turning off of this response. We here report an early (within minutes) immunostimulatory involvement of PGE2 (and thromboxane A2) in the sheep, with prompt elevations in levels of PGE2 and thromboxane B2 in popliteal lymph node efferent lymph following drainage area immunization with killed Salmonella muenchen bacteria. These elevations were associated with an increase in efferent lymph flow and an equally prompt but limited depression of lymphocyte outputs into efferent lymph ('shutdown', 'recruitment'). Local increases in blood flow and vascular permeability probably play important roles in these events.

Intestinal apolipoprotein synthesis and secretion in the suckling pig

The present studies report characterization of intestinal apolipoprotein (apoLp) synthesis and secretion in the suckling pig. Lipoproteins (d less than 1.006 g/ml) from mesenteric lymph were found to contain both apoB-100 and B-48, in addition to apoA-IV, E, A-I, and Cs. Lymph low density lipoproteins (LDL) and high density lipoproteins (HDL) contained mainly apoB-100 and apoA-I, respectively. Analysis of core cholesteryl ester fatty acid composition suggested filtration from plasma as the major source of lymph LDL and HDL. Dual radioisotope labeling of intestinal and hepatic apoLps in lymph, as well as immunoprecipitation of radiolabeled intestinal mucosa, demonstrated intestinal synthesis of apoB-48, A-IV, and A-I. There was no evidence for apoB-100 synthesis by intestinal mucosa. By contrast, piglet liver synthesized apoB-100, E, A-I, and Cs, but not apoB-48. Newly synthesized intracellular intestinal apoA-I was mainly (basic) isoform 1 (pI 5.58), while lymph and plasma HDL apoA-I were predominantly isoform 3 (pI 5.33), mature apoA-I. Lymph apoB (P less than 0.001) and apoA-I (P less than 0.04) mass output increased significantly during lipid absorption. Studies were subsequently conducted in fasting, fat-fed, bile-diverted, and sham-operated animals to determine the role of both dietary and biliary lipid in regulating intestinal apoLp biosynthesis. Proximal and distal small intestinal loops were pulse-radiolabeled with [3H]leucine, and apoB-48 and A-I were immunoprecipitated from cytosolic supernatants. Although a proximal to distal gradient in intestinal synthesis rates for both apoB and A-I was noted in all groups, the acute absorption of dietary lipid did not significantly increase apoB or A-I synthesis in either location. Complete removal of biliary lipid for 48 hr did not alter synthesis rates in jejunum or ileum. These studies suggest that mesenteric lymph apoLps in the suckling pig are derived both by filtration from plasma and by direct secretion from the intestine. Physiologic regulation of intestinal apoA-I and B-48 synthesis rates appears to be independent of luminal lipid availability.

Lipoxygenase products induce neutrophil activation and increase endothelial permeability after thrombin-induced pulmonary microembolism

We examined the mechanism of the neutrophil (PMN)-dependent increase in pulmonary vascular permeability to protein after thrombin-induced pulmonary microembolism. Humoral factors that activate PMNs after thrombin-induced pulmonary microembolism were characterized in pulmonary lymph obtained from unanesthetized sheep challenged with intravenous infusion of alpha-thrombin. Time-dependent increases in PMN migration, aggregation, and superoxide anion (O2-) generation were induced by the pulmonary lymph obtained within 20 minutes after thrombin infusion. The pulmonary lymph neutrophil activating factors present in ether extracts of lymph had retention times of leukotriene B4 (LTB4) and monohydroxyeicosatetraenoic acids (HETEs) by high-performance liquid chromatography. The postthrombin lymph samples containing the LTB4 and HETEs increased PMN O2- generation and endothelial monolayer permeability to 125I-albumin in the presence of PMNs layered on the endothelial monolayers. Control lymph samples replete with LTB4, 5-HETE, and 15-HETE induced increases in PMN O2- generation and endothelial monolayer permeability to 125I-albumin in the presence of PMNs layered on the endothelial monolayers. Maximal increases in PMN O2- production and endothelial permeability occurred when LTB4, 5-HETE, and 15-HETE were coincubated with PMNs, indicating a synergistic action of these mediators in inducing PMN activation. Endothelial monolayer permeability to 125I-albumin did not increase with postthrombin lymph samples obtained after pretreatment with the 5-lipoxygenase inhibitor, L-651,392. The results indicate that lipoxygenase products generated in the lungs after thrombin-induced microembolism contribute to increased endothelial permeability secondary to PMN activation.

Limb ischemia-induced increase in permeability is mediated by leukocytes and leukotrienes

This study tests the role of white blood cells (WBC) and leukotrienes in mediating the increased microvascular permeability following ischemia and reperfusion. Anesthetized dogs (n = 23) underwent 2 hours of hind limb ischemia induced by tourniquet inflation to 300 mmHg. In untreated animals (n = 7), tourniquet release led after 5 minutes to a rise in plasma thromboxane (Tx) B2 levels from 360 to 1702 pg/ml (p less than 0.05); after 2 hours, lymph TxB2 concentration had risen from 412 to 1598 pg/ml (p less than 0.05). There were decreases in circulating WBC from 11,766 to 6550/mm3 and platelets from 230 to 155 x 10(3)/mm3. During reperfusion, popliteal lymph flow (QL) increased from 0.07 to 0.24 ml/hour (p less than 0.05), while the lymph/plasma (L/P) protein ratio was unchanged from 0.39, changes consistent with increased microvascular permeability. WBC depletion (n = 7) to 302/mm3 by hydroxyurea or nitrogen mustard attentuated (p less than 0.05) the reperfusion induced rise in plasma TxB2 from 91 to 248 pg/ml and prevented the increase in lymph TxB2 concentration. Within 5 minutes of tourniquet release WBC counts further decreased to 191/mm3 (p less than 0.05) and platelets declined from 175 to 93 x 10(3)/mm3 (p less than 0.05). QL increased from 0.07 to 0.12 ml/hour (p less than 0.05), lower than untreated animals (p less than 0.05), and the L/P protein ratio declined from 0.49 to 0.37 (p less than 0.05), dilutional changes consistent with increased filtration pressure but not permeability to protein. Pretreatment with the lipoxygenase inhibitor diethylcarbamazine (DEC) (n = 8) prevented the reperfusion-induced increase in plasma and lymph TxB2 levels (p less than 0.05) and the fall in WBC counts (p less than 0.05), while platelet counts declined from 381 to 210 x 10(3)/mm3 (p less than 0.05). QL rose from 0.09 to 0.23 ml/hour (p less than 0.05) during reperfusion, and the L/P protein ratio of 0.3 remained unchanged, a value lower than in untreated dogs (p less than 0.05). In two animals of each group, vascular recruitment was induced by tourniquet inflation to 50 mmHg. This led to a high QL of 0.25 ml/hour and a low L/P ratio of 0.18. In untreated animals during reperfusion, QL further increased to 1.3 ml/hour, and L/P ratio rose to 0.44, documenting increased vascular permeability. In contrast, reperfusion in leukopenic or diethylcarbamazine (DEC)-treated dogs with vascular recruitment, was not associated with increases in QL or the L/P protein ratio.(ABSTRACT TRUNCATED AT 400 WORDS)

Phospholipids from the hepatopancreas of Indian horseshoe crab Carcinoscropius rotundicauda

Total phospholipids were extracted from the heart, hepatopancreas, and hemolymph of the Indian horseshoe crab Carcinoscorpius rotundicauda by the conventional method. Characteristic group reaction and 2-dimensional thin-layer chromatography on silica gel were used for identification of different phospholipids. The phospholipid profile obtained from hemolymph and 2 major organs are comparable and show phosphatidyl choline (PC) and phosphatidyl ethanolamine to be the major phospholipids. A phospholipid has been consistently detected migrating immediately below the PC in the thin-layer chromatogram of lipids extracted from the hepatopancreas. When mixed methyl esters of this slower moving PC are resolved on a silica gel plate ran in hexane ether:acetic acid 80:20:1, with appropriate controls, an additional spot is seen just below the normal methyl ester, indicating a difference between the fatty acid compositions of 2 PC (e.g., regular and slower). The slower mixed methyl esters were found to comprise mainly the 4 saturated fatty acids: lauric, myristic, palmitic, and stearic. The slow moving PC seems to consist mainly of molecular species with the above-mentioned saturated fatty acids at both Sn 1 and Sn 2 positions.

Lower torso ischemia-induced lung injury is leukocyte dependent

Lower torso ischemia leads on reperfusion to sequestration of polymorphonuclear leukocytes (PMN) in the lungs and increased permeability. This study tests the role of circulating leukocytes (WBC) in mediating this lung injury. Anesthetized sheep prepared with chronic lung lymph fistulae underwent 2 hours of bilateral hind limb tourniquet ischemia. In untreated controls (n = 7), 1 minute after reperfusion there were transient increases in mean pulmonary arterial pressure (MPAP) from 13 to 38 mmHg (p less than 0.05) and pulmonary microvascular pressure (Pmv) from 7 to 18 mmHg (p less than 0.05), changes temporally related to a rise in plasma thromboxane (Tx) B2 levels from 211 to 735 pg/ml (p less than 0.05). Lung lymph TxB2 levels rose from 400 to 1005 pg/ml at 30 minutes (p less than 0.05), and remained elevated longer than plasma levels. Lung lymph flow (QL) rose from 4.3 to 8.3 ml/30 minutes (p less than 0.05) after 30 minutes of reperfusion and remained elevated for 2 hours. The lymph/plasma (L/P) protein ratio was unchanged from 0.6, while the lymph protein clearance increased from 2.6 to 4.6 ml/30 minutes (p less than 0.05), suggesting increased microvascular permeability. WBC counts decreased within the first hour of reperfusion from 6853 to 3796/mm3 (p less than 0.05), and lung histology after 2 hours showed proteinaceous exudates and leukosequestration of 62 PMN/10 high-powered fields (HPF), higher than the 22 PMN/10 HPF (p less than 0.05) in sham animals (n = 3). Recruitment of the pulmonary vasculature by left atrial balloon inflation (n = 3) resulted in a rise in MPAP to 20 mmHg. After 3 hours of balloon inflation, QL stabilized at 9.8 ml/15 minutes, and a pressure-independent L/P protein ratio of 0.3 was achieved. During reperfusion, QL increased further to 11.2 ml/15 minutes, the L/P ratio rose to 0.56 and the calculated osmotic reflection coefficient decreased from 0.70 to 0.44, documenting an increase in lung microvascular permeability. In contrast to these untreated ischemic controls, sheep (n = 7) rendered leukopenic with hydroxyurea or nitrogen mustard and having a total WBC count of 760/mm3 and PMN count of 150/mm3 did not manifest reperfusion-induced increases in MPAP, Pmv, QL, lymph protein clearance, or lung lymph. TxB2 level (p less than 0.05). Plasma TxB2 levels rose slightly at 30 minutes from 199 to 288 pg/ml (p less than 0.05). Lung histology was normal. These data indicate that WBC mediate the ischemia-induced increase in pulmonary microvascular permeability.

Local abnormalities of coagulation and fibrinolysis and alveolar fibrin deposition in sheep with oleic acid-induced lung injury

Extravascular, primarily intra-alveolar, fibrin deposition is a histologic hallmark of acute lung injury in humans and experimental animals, but the mechanisms leading to this finding are poorly understood. To determine whether local abnormalities in the fibrinolytic-procoagulant balance contribute to alveolar fibrin deposition in acute lung injury, we studied bronchoalveolar lavage (BAL) fluids of anesthetized sheep that received intravenous oleic acid. Prominent alveolar fibrin deposition was observed within 2 h after oleic acid-induced lung injury. Procoagulant and fibrinolytic activities were determined in BAL samples of anesthetized, mechanically ventilated sheep before and 2 h after intravenous oleic acid or saline. BAL procoagulant activity was found to be due mainly to tissue factor associated with Factor VII. In baseline BAL samples, we found relatively low levels of procoagulant activity and relatively high levels of fibrinolytic activity. After induction of oleic acid-induced lung injury, the procoagulant activity of BAL was markedly increased, whereas fibrinolytic activity was either depressed or undetectable. Antiplasmin activity was detectable in BAL of sheep after oleic acid-induced lung injury, which contributed at least in part to the depressed fibrinolytic activity observed. These perturbations occurred with the appearance of extensive alveolar fibrin deposition. In control sheep, BAL fibrinolytic activity was decreased, and antiplasmin activity increased modestly after 2 h of mechanical ventilation, but procoagulant activity was unchanged and alveolar fibrin was not observed. Procoagulant activity in lung lymph and plasma after lung injury did not differ from baseline values, and fibrinolytic activity was undetectable in lymph or plasma samples. These data indicate that increased procoagulant activity and concurrent disruption of the balance of coagulation and fibrinolysis establish local conditions that promote acute fibrin deposition in the alveoli of mechanically ventilated, oleic acid-injured sheep.

The lymphatic route. V. Distribution of human natural interferon-beta in rabbit plasma and lymph

Human natural interferon-beta (HuIFN-beta) was administered through different routes (intravenous [i.v.], intramuscular [i.m.], and subcutaneous [s.c.]) and its distribution in lymph and plasma was evaluated. After i.v. (bolus) administration the lymph/plasma ratio was about 0.35 but it significantly increased (11-fold) after i.m. administration. Addition of human albumin (ALB) to the IFN solution did not favor IFN absorption through the lymphatics. On the other hand, addition of ALB improved IFN absorption through the lymphatics after s.c. administration. These results are interesting because they clarify why IFN-beta can exert immunomodulatory activities in spite of very low plasma levels.

Bradykinin-mediated edema formation is blocked by levorotatory but not dextrorotatory terbutaline

The ability of the purified stereoisomers of the beta 2-receptor agonist terbutaline to block bradykinin-mediated increases in lymph flow and protein concentration was assessed in the canine forelimb perfused at constant arterial flow. Intra-arterial infusion of bradykinin (2 micrograms/min, n = 8) decreased forelimb arterial pressures but did not affect skin small vein pressure or systemic pressure. Lymph flow, protein concentration and protein transport were significantly increased. Intra-arterial infusion of 1-terbutaline (1 microgram/min, n = 9) decreased forelimb arterial pressures and systemic pressure but did not affect lymph parameters. Subsequent infusion of bradykinin during the continued infusion of 1-terbutaline failed to alter forelimb lymph parameters. Intra-arterial infusion of d-terbutaline (1 microgram/min, n = 11) did not alter vascular pressures or lymph parameters. Subsequent infusion of bradykinin during the continued infusion of d-terbutaline decreased forelimb arterial pressures and significantly increased lymph flow, protein concentration and protein transport. Intra-arterial infusion of a high dose (100 micrograms/min, n = 9) of d-terbutaline significantly decreased forelimb arterial pressure but was likewise ineffective in blocking the increases in lymph parameters produced by subsequent bradykinin infusion. These data indicate that the beta 2-receptor agonistic and anti-permeability actions of terbutaline are found solely in the levorotatory enantiomer.

Combined monitoring of thoracic duct and lung lymph during E. coli sepsis in awake sheep

A thoracic duct lymph fistula in combination with a lung lymph fistula in the awake sheep was used to evaluate effects of thoracic lymph diversion during a septic insult and to monitor systemic and local changes in the lung and gastrointestinal tract. Live Escherichia coli 10(9) kg-1 b.w. were infused in 9 sheep. After sepsis, arterial pressure, cardiac output, partial pressure of oxygen, leukocytes and platelets decreased significantly compared to baseline values. Pulmonary arterial pressure increased significantly throughout the experiment with peak values at 44 +/- 4 mmHg after 15 minutes. Lung lymph flow (QL) (n = 6) increased from 23 +/- 0.5 to 11.2 +/- 2.4 ml/30 minutes after 60 minutes. QL then decreased but remained elevated. Lymph to plasma protein concentration ratio (L/P) in lung lymph decreased from 0.62 +/- 0.02 during baseline to 0.47 +/- 0.04 after 60 minutes. L/P then increased and was, after 150 minutes, no longer different from baseline. These lung lymph data favor increased pulmonary microvascular permeability during sepsis. Lymph flow in the thoracic duct (QT) (n = 9) increased from 34.2 +/- 6 to 58.3 +/- 9 ml/30 minutes during the first 30 minutes after bacterial infusion. QT was, after 90 minutes, back to baseline but then progressively increased. L/P in thoracic lymph steadily increased from 0.56 +/- 0.03 to 0.78 +/- 0.04. Thromboxane B2 and 6-keto PGF1 alpha in thoracic duct and lung lymph increased significantly after bacterial infusion and remained elevated thereafter. Combined monitoring of thoracic duct and lung lymph enabled comparison of systemic and pulmonary reactions in septic sheep.

Characterization of dog prenodal peripheral lymph lipoproteins. Evidence for the peripheral formation of lipoprotein-unassociated apoA-I with slow pre-beta electrophoretic mobility

Dog plasma and prenodal peripheral lymph apoA-I distribution was examined by nondenaturing gradient gel electrophoresis-immunoblot analysis. In control dogs, plasma apoA-I could be localized to two distinct populations of particles with modal diameters of 8.4 nm and 10.4 nm. The smaller sized population accounted for over 50% of plasma apoA-I. Peripheral lymph apoA-I distribution was significantly different. The percentage of apoA-I localized to the 10.4 nm population was reduced by 40% and the modal diameter of the smaller HDL apoA-I population was significantly decreased by 0.1 nm. Additionally, peripheral lymph apoA-I could be localized to particles smaller than albumin (lipoprotein-unassociated apoA-I). The presence of lipoprotein-unassociated apoA-I particles was confirmed by gel filtration chromatography. Immunoblots of column fractions subjected to agarose electrophoresis revealed that these particles had slow pre-beta electrophoretic mobility. In dogs fed an atherogenic diet, lipoprotein-unassociated apoA-I particles with slow pre-beta electrophoretic mobility could be found in both plasma and peripheral lymph. With increasing degree of hypercholesterolemia, the relative amount of plasma lipoprotein-unassociated apoA-I tended to increase. In peripheral lymph, an increasing degree of hypercholesterolemia was associated with a decrease in the relative amount of lipoprotein-unassociated apoA-I. Instead, a population of large apoA-I particles (11-25 nm) became increasingly prominent.

Pulmonary vascular response to platelet-activating factor in conscious sheep

Hemodynamic response to an intravenous infusion of platelet-activating factor (PAF; 1 microgram/kg) was studied in conscious sheep with lung lymph fistulas. PAF induced increases in pulmonary arterial pressure and decreases in left atrial and systemic arterial pressures and in cardiac output, together with transient increases in thromboxane (Tx) A2 (as TxB2) and prostacyclin (as 6-keto-PGF1 alpha) values in plasma and lung lymph. There were also transient decreases in circulating leukocytes and platelets. The second infusion of PAF induced a reduced response compared with the first one, but the response to PAF was afterward maintained. Pretreatment with OKY 046, a thromboxane synthase inhibitor, reduced the first pulmonary vasoconstriction in response to PAF to a degree equivalent to that after successive infusions of PAF in control sheep. Pulmonary response to PAF (except on first infusion) and systemic cardiovascular response did not change whether or not TxA2 was produced. We therefore concluded that PAF mediates pulmonary and systemic cardiovascular effects via mechanisms other than TxA2 during successive infusions of PAF and that PAF-induced TxA2 contributes only to the pulmonary response to PAF on first infusion of the latter.

Inhibitors of sterol synthesis. A major role of chylomicrons in the metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one in the rat

The metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one (I), a potent regulator of cholesterol (Chol) metabolism which has significant hypocholesterolemic activity upon oral administration to animals, has been investigated in male rats. After intragastric administration of [2,4-3H] I and [4-14C]Chol in triolein to intestinal lymph duct-cannulated rats, most of the 3H of the lymph was associated with chylomicrons. Most of the 3H in the chylomicrons was associated with fatty acid esters of I and the oleate ester represented the major species of the esters of I. After intravenous injection of the isolated doubly-labeled chylomicrons to intact rats, rapid clearance of 3H and 14C from blood was observed which was associated with a rapid and selective uptake of 3H and 14C by liver. The rate of disappearance of 3H from blood and the rate of uptake of 3H by liver were similar, if not identical, to those for 14C. In contrast, the disappearance of 3H from the liver was much more rapid than that of 14C. Studies of the distribution of 3H in liver demonstrated rapid formation of free I and the formation of [3H]Chol. In addition, significant amounts of the 3H in liver were associated with polar materials, a finding which was not observed in the case of 14C. After intravenous administration of the doubly-labeled chylomicrons to bile duct-cannulated rats, very rapid and substantial metabolism of the administered 3H to polar biliary metabolites was observed. The bulk of the 3H not recovered in bile at 49 h after the injection of the labeled chylomicrons was recovered in blood and tissues and almost all (integral of 94%) of this material was associated with Chol and Chol esters. The combined results indicate an important role for chylomicrons in the overall metabolism of I. The selective delivery of I to liver as its oleate ester in chylomicrons (or, more probably, as chylomicron remnants) and the subsequent metabolism of the oleate ester of I in liver has important consequences with respect to the actions of I which are discussed herein.

Insulin-like growth factor (IGF) and IGF-binding proteins: comparison of human serum and lymph

The extent to which the association between insulin-like growth factors (IGFs) and their specific binding proteins (BPs) prevents their crossing the capillary barrier was studied by comparing their distribution in serum with that in samples of lymph collected from the lower leg of five subjects undergoing radiographical investigation of the lymphatic system. The IGF concentrations in lymph were 10-30% of the corresponding serum levels, and in each subject the ratios of IGF-I and IGF-II in the lymph to those in the serum were similar. Western blot analysis of the BPs revealed that the five molecular forms identified in serum also were present in lymph, but in significantly smaller quantities. The 41.5K and 38.5K forms, which constitute the binding units of the large complex (approximately 150K) of serum and are also capable of binding IGFs in monomeric form, were present in smaller amounts than the 34K, 30K and 24K forms, which belong specifically to the small complex (approximately 40K) of serum. The BPs extracted from lymph were similar to those of the small complex, with a preferential affinity for IGF-II and only half of the affinity for IGF-I of the BPs extracted from serum. With neutral pH gel filtration of lymph, more than 90% of IGFs and binding activity eluted with the material in the area of the 40K zone. These data indicate that the 150K IGF-BP complexes do not cross the capillary barrier, whereas the 40K complexes do. The function of the former may be to provide a reservoir and buffering action of the IGFs, whereas the latter may be involved in the transport of the IGFs to their target cells.

Effects of coronary ischemia on lung fluid balance in conscious sheep

It has been suggested that coronary ischemia increases extravascular lung water. To determine whether pulmonary microvascular permeability is increased by coronary ischemia, we measured pulmonary hemodynamics, lung lymph flow (QL), and lymph-to-plasma protein concentration ratio (L/P) in 12 sheep with chronic lung lymph fistulas. Studies were done in 3 groups: in group 1 (n = 7) a marginal branch of the left circumflex artery (Lcx) was occluded, in group 2 (n = 5) left atrial pressure (Pla) was mechanically raised by 10 mmHg, and in group 3 (n = 5) Lcx was occluded and Pla was raised by 10 mmHg. In group 1, coronary occlusion increased QL (4.6 +/- 0.4 to 8.3 +/- 2.6 ml/h) without changes in L/P. In group 2, elevated Pla increased QL (5.1 +/- 1.2 to 10.1 +/- 3.0 ml/h) with decreases in L/P (0.71 +/- 0.02 to 0.61 +/- 0.02). In group 3, coronary occlusion with elevated Pla caused a further increase in QL (5.0 +/- 1.5 to 16.9 +/- 4.6 ml/h) without significant decreases in L/P (0.71 +/- 0.01 to 0.65 +/- 0.06). Lung lymph concentrations of 6-keto-prostaglandin F1 alpha (a degradation product of prostacyclin) increased transiently after coronary occlusion. These results indicate that coronary occlusion can increase transcapillary protein transport in lungs of conscious sheep and simultaneously increase prostacyclin production in the lung.

Effects of scalding injury on the components of rabbit paw lymph

A technique for lymph collection has been described. Rabbit paw lymph was collected by this technique before and after scalding injury (75 degrees C for 20 s). The lymph concentrations of zinc, copper, iron, cobalt and lipid peroxide were measured. After scalding, the lymph flow increased rapidly and reached a maximum at 1 h, and then decreased gradually. The lymph concentrations of copper, iron and cobalt increased about two-fold in the first 30 min and the elevated levels persisted until 4 h. However, the increase of zinc was less than that of the other three metals. Total protein concentrations also increased twofold in lymph and the elevated level persisted for 4 h. Using gel filtration, the elution pattern of lymph after scalding was almost the same as that before scalding. Lipid peroxide in lymph increased about three-fold following scalding. However, the plasma concentrations of total protein and lipid peroxide did not change significantly following scalding.

The effect of leukocyte depletion on smoke inhalation injury in sheep

Leukocytes and the production of oxygen radicals and proteolytic enzymes have been implicated in the pathogenesis of lung injury after smoke inhalation. We investigated the mechanism responsible for this form of pulmonary damage in chronically prepared sheep previously made leukopenic with intra-arterial infusions of nitrogen mustard (mechlorethamine hydrochloride). A control air insufflated group (sham: n = 6), a cotton smoke insufflated group (smoke: n = 12), and a leukopenic cotton smoke insufflation group (smoked + depleted: n = 6) were compared. Although both smoke insufflation groups had equivalent smoke exposure, which was indexed by carboxyhemoglobin, the smoked + depleted group had significant attenuation in the increases in pulmonary artery pressure, pulmonary vascular resistance, and pulmonary lymph flow. The PaO2 to FiO2 ratio (P:F) did not fall to the same extent, nor was there a fall in PaO2. The production of oxygen radicals, which was measured as plasma-conjugated dienes, and the consumption of antiprotease, as measured by alpha 2-macroglobulin levels in lung lymph, were not changed in the smoked + depleted group, whereas it was elevated in the smoked group. We conclude that circulating leukocytes and the release of oxygen radicals and proteolytic enzymes contribute to the lung injury, pulmonary microvascular permeability increase, and pulmonary edema seen after smoke inhalation.

Epidermal cell thymocyte activity factor/interleukin 1 (ETAF/IL)-like activity in lymph drained from normal human skin

Lymph derived from human skin contains lymphocytes which have a high rate of spontaneous blastic transformation in culture and are highly responsive to lectins. This phenomenon suggests that either a subpopulation of highly responsive lymphocytes is extravasated into skin, or skin tissue fluid and lymph contain humoral factors co-stimulating lymphocytes upon contact with tissue antigens. We sought to determine whether human prenodal lymph drained from normal leg skin possesses lymphokine activity. Significant augmentation of lectin induced thymocyte and autologous blood lymphocyte proliferation was produced by lymph. The augmenting activity was abrogated by incubation of lymph with anti-IL-1 antiserum. Supernatant from cultured lymph cells (lymphocytes, Langerhans cells) did not augment either thymocyte or autologous blood lymphocyte proliferation. No interleukin 2 activity was found in lymph. The data indicate that skin lymph possesses epidermal cell thymocyte activating factor/interleukin (ETAF/IL) 1-like activity which is not found in serum and that the main source of the putative lymphokine is epidermal and not migrating lymph mononuclear cells.

Cardiopulmonary changes with intermittent endotoxin administration in sheep

Chronic sepsis was induced by administering endotoxin (lipopolysaccharide--LPS) at 12-hr intervals to sheep. The animals (n = 7) responded to the first dose of LPS with increased pulmonary arterial pressure (PAP), systemic vascular resistance, plasma and lymph thromboxane B2 (TxB2) concentrations, and lung lymph flow rate concurrent with a reduction in the cardiac index (CI). Subsequent doses of LPS produced an elevation of PAP and TxB2 which was progressively attenuated and eventually disappeared. With LPS the lung lymph flow was markedly elevated and CI increased. This latter was transient and associated with a reduction in systemic vascular resistance. Concomitant with the cardiopulmonary changes prekallikrein levels were not diminished, but there was a statistically significant reduction in C1-esterase inhibitor. The administration of LPS was discontinued after 5 days and the cardiopulmonary variables rapidly returned to baseline levels. Chronic endotoxemia appears to be associated with an elevated pulmonary microvascular permeability and a tendency toward a hyperdynamic circulation but with an appreciable degree of refractoriness associated with regional hemodynamics and eicosanoid biosynthesis.