The role of lymphatics in the formation of ascites complicating schistosomal hepatic fibrosis

The total protein content in plasma, ascitic fluid, thoracic duct lymph, hepatic and intestinal lymph was studied in a series of 15 patients suffering from schistosomal hepatic fibrosis and intractable ascites. Pure schistosomal cases with presinusoidal resistance to portal blood flow have excessive thoracic duct lymph low in protein. The main source of such excess lymph is the extra-hepatic portal bed. Ascitic fluid in such patients has a low protein content and has the character of a transudate. The bulk of such peritoneal fluid seems to originate largely from the excess extrahepatic portal lymph.

The transcapillary exchange of thyroid hormones and thyroxine-binding proteins between blood and tissue fluids

A study has been made of the relative importance of potien bound and unbound hormone in the exchange of thyroid hormones between blood and interstitial fluid. 2. When [I] tyroxine (or thriiodothyronine) and [I] human serum albumin were injected simultaneously into the circulation of sheep with chronic lymphatic fistulae, the thyroid hormones were removed from the circulation and apperaed in all lymph samples at a greater fractional rate than human serum albumin. 3. The steady-state lymph/plasma concentrations ratios of the two specific thyroxine binding proteins were similar to each other and to those of albmin and total thyroxine. 4. Gel filtration studies indicated that the two specific thyroxine binding proteins, ovine serum albumin and human serum albumin, were all of similar molecular size. 5. Concentrations of unbound thyroxine in plasma and various samples of lymph from the one animal were similar. 6. Increasing the proportion of thyroid hormone that was unbound resulted in an increase rate of equilibration of labelled hormone between blood plasma and lymph. 7. Perfusion of the popliteal lymph node demonstrated that thyroid hormones were removed from lymph during its passage through the node. The amount removed was related to the proportion of hormone in the unbound state.

[Effect of ursodesoxycholic acid and cholic acid on intestinal absorption of cholesterol]

A study was carried out to investigate the effect of ursodesoxycholic acid and cholic acid on intestinal absorption of cholesterol-4-14C administered p.o. to lymph-fistula rats. The results indicated that within 24 hours, the labeled cholesterol detected in thoracic duct lymph of the control group was 21.0% of the administered cholesterol-4-14C, whereas the group treated with cholic acid (250 mg/kg p.o.) was found to have an increased value of 30.6% absorbed cholesterol. In comparison, the group treated with the same dose of ursodesoxycholic acid showed a decreased value of 12.1%, indicating an inhibitory effect on cholesterol absorption by the compound. This differential effect of the two compounds was also observed in a time-course study.

Serum lysozyme as a marker of host resistance. I. Production by macrophages resident in rat sarcomata

With progressive growth of syngeneic sarcomata in rats there was a rise in serum levels of lysozyme which correlated with their immunogenicity and their macrophage content. By an examination of lymph/blood differences in normal and in tumour bearing rats and of the production of lysozyme by cells obtained from the tumours and maintained in vitro, it is apparent that the macrophages resident in a tumour mass make a massive contribution to the elevation in serum lysozyme concentrations. Tumour cells did not release detectable lysozyme activity. Tumour amputation led to a rapid fall in lysozyme levels. Irradiation of the host rats abolished the lysozyme response and the subsequent development of metastases in these rats was associated with a rise in serum lysozyme. The serum concentration of this enzyme reflects the macrophage content of a tumour mass and the draining lymph nodes. We conclude that under well defined conditions serum lysozyme activity may be a useful marker of macrophage mediated host responses to a tumour.

New interpretations of lipoproteins and arterial lesions of cholesterol-fed rabbits

The serum of cholesterol-fed rabbits contains lipoproteins rich in cholesterol, in contrast to those in thoracic duct lymph, which are rich in triglyceride. This study suggests that the serum lipoproteins may be "remnant" chylomicrons which have been stripped of their triglyceride, but which have not been removed from circulation by the liver, as usually occurs rapidly in other animal species. Electrophoresis of rabbit serum showed a broad beta band corresponding to the very low density lipoprotein fraction separated by ultracentritrifugation. This broad beta band may represent the "remnant particles". This proposed "remnant particle" hyperlipidaemia in rabbits may have its parallel in Type III human hyperlipidaemia, which also has a broad beta band on electrophoresis and may be a "remnant particle" disease. It was also found that early arterial lesions in rabbits are similar to some human fatty streaks, which if allowed to age for a further two years while the rabbits eat normal food, do not regress but mature to resemble calcified fibrous plaques.

Protein content of liver lymph in patients with portal hypertension secondary to hepatic cirrhosis

Protein content of liver lymph was measured in 14 patients with portal hypertension secondary to advanced hepatic cirrhosis. An abnormally low concentration was found in each patient, averaging 52% of plasma levels. This finding reflects a decreased sinusoidal permeability to protein, the possible effect of "capillarization of the sinusoid" and may bear on development of portal congestion.

The effect of anaesthesia and surgery on lymph flow, protein and leucocyte concentration in lymph of the sheep

Anaesthesia and the trauma of surgery, associated with the cannulation of lymphatic ducts in various regions of the body of the sheep, had a profound effect on lymph flow, protein concentration and leucocyte concentration of lymph. In general lymph flow was depressed and the protein concentration elevated in lymph collected at the time of cannulation, or within the first 24 hours of recovery from surgery. The changes in protein concentration in lymph draining the peripheral regions of the body appeared to be due to surgical interference in the region of drainage. The greatest changes in lymph flow were observed in lymph draining peripheral regions (skin, tendon, muscular areas) while lymph draining soft tissues in central regions (kidney, liver) was less affected by the anaesthesia and surgical stress. A neutrophilia was observed in venous blood collected under anaesthesia while the overall numbers of lymphocytes in three sources of efferent lymph were depressed. It is suggested that corticosteroid hormones may play a role in the changes in leucocyte migration observed during anaesthesia and surgical stress. Changes observed in the cellular content of afferent lymph appeared to be due to a low grade inflammation associated with surgical interference in the region of lymphatic drainage.

High concentration of bilirubin in post-nodal lymph associated with red blood cell catabolism in lymph nodes of the sheep

Qualitative and quantitative analysis of post-nodal lymph of the sheep has shown that the distinct yellow colour of this fluid pool is due to the presence of relatively large amounts of bilirubin. In efferent lymph from thepopliteal, prefemoral, prescapular, renal and intestinal lymph nodes total bilirubin concentrations were 3-8 times higher than the corresponding concentrations in blood plasma. In contrast the total bilirubin concentrations in afferent lymph from the lower leg and kidney were less than the corresponding concentrations in blood plasma. Histological examination of several popliteal and mesenteric lymph nodes revealed the presence of free iron and bilirubin in the cytoplasm of cells located near the lymphatic sinuses of the node. In addition, the concentration of bilirubin in efferent lymph from the popliteal node was observed to increase following an induced rise in the number of red blood cells reaching the node by way of the afferent lymphatic duct. These latter observations suggest that the bilirubin in post-nodal lymph is associated with the catabolism of extravascular red cells by reticulo-endothelial cells within the lymph nodes.

Observations on the passage of apoproteins from plasma lipoproteins into peripheral lymph in two men

1. The passage of radioactive apolipoproteins into lymph draining the foot was investigated in two men, each given a single intravenous injection of low-density lipoprotein containing 131I-labelled apoprotein B and of very-low-density lipoprotein containing 125I-labelled apoprotein A and apoprotein C. 2. Protein-bound 125I and 131I appeared in the lymph of both subjects. Immunoelectrophoresis of lymph lipoproteins against anti-(high-density lipoprotein) and anti-(low-density lipoprotein) showed the presence of apo-high-density lipoprotein and apo-low-density lipoprotein with faster mobilities than plasma high-density and low-density lipoprotein respectively. Most of the protein-bound 131I in lymph was recovered in the precipitin line formed by the apoprotein B-containing lipoprotein after immunoelectrophoresis. Polyacrylamide gel electrophoresis of the lymph lipoprotein fraction showed the presence of 125I-containing bands with mobilities similar to those of the apoprotein A of high-density lipoprotein and of three of the fast-moving C apoproteins. 3. These results suggest that most, if not all, of the apoproteins of plasma lipoproteins reach the interstitial fluids and that some lipoproteins undergo modification during their passage into peripheral lymph.

Chylomicron formation and composition in unanaesthetised rabbits

Emulsified lipid was infused steadily into the upper small intestine of unanaesthetised rabbits for 6 h and 24 h periods. Lymph was collected from a thoracic duct cannula, the output of infused lipids was measured and the lymph chylomicrons were isolated. Recovery of infused triacylglycerol was 63 +/- 6.4% and recovery of infused radioactive cholesterol was 24 +/- 4.2% during a 24 h period. There was considerable dilution of radioactive exogenous cholesterol with endogenous cholesterol. Provided that absorption was well-established most exogenous lipid was present in the lymph in the form of chylomicrons, and there was a close relationship between lipid content of the lymph and the presence of chylomicrons. During absorption of fats of differing fatty acid composition chylomicrons remained the predominant transport form in the lymph. Chylomicrons obtained during absorption of several fats have been analysed in detail. The protein, phospholipid, free and esterified cholesterol content of these chylomicrons varies within narrow limits. The fatty acid composition of chylomicron triacylglycerols reflects the type of fat in the test meal but the composition of chylomicron phospholipids and cholesteryl esters shows clear discrimination. During absorption of coconut oil there is a strong negative discrimination towards lauric acid both for cholesteryl esters and for phospholipids.

Effect of increased vascular pressure on lung fluid balance in unanesthetized sheep

In 20 unanesthetized sheep, we measured lung lymph flow and lymph and plasma protein concentrations during steady-state base-line conditions and during steady-state elevations of pulmonary microvascular hydrostatic pressure (range 3 to 23 cm H2O). In every sheep there was a base-line lung lymph flow (average 5.7 +/- 2.5 (SD) ml/hour), demonstrating that net fluid filtration occurred. The base-line lymph-plasma total protein ratio averaged 0.69 +/- 0.05, indicating a high protein osmotic pressure in the interstitial fluid at the filtration site. Lymph flow increased and lymph protein concentration decreased approximately linearly whenever hydrostatic pressure rose. A new steady-state condition was reached in 1-2 hours. The difference in plasma-to-lymph protein osmotic pressure increased by half the hydrostatic pressure increment (50% negative feedback regulation). Extravascular lung water content, measured post-mortem, did not change significantly until microvascular hydrostatic pressure more than doubled, indicating a large safety factor that protects the lungs against fluid accumulation normally. The major contributions to the safety factor appeared to be a sensitive and efficient lymph pump coupled to a washout of interstitial protein. The fluid filtration coefficient, whose calculation required many assumptions, averaged 1.64 +/- 2.65 ml/(cm H2O times hour) in the base-line condition and did not change significantly over the pressure range studied.

Comparison of hilar and capsular renal lymph

The sites of origin of renal lymph were studied by analysis of simultaneously collected samples of lymph and plasma. The samples included renal hilar (HL) and capsular lymph (CL), thoracic duct lymph (TD), renal venous (RVP) and arterial plasma (AP), and were analyzed for Na+, Cl-, K+, urea, glucose, inulin, and PAH concentrations. The glucose concentrations of HL (76 mg/100 ml, SE +/- 1.9), and CL (92 mg/100 ml, SE +/- 2.5) were significantly different (P less than 0.01) from that of RVP (86 mg/100 ml, SE +/- 2.2). Concentrations of both inulin and PAH in CL and HL fell between the AP and RVP values. The concentration of inulin in CL (CL/RVP = 1.27) exceeded that in HL (HL/RVP = 1.10), but no such difference was detected for PAH. The Na+ (152 meq/liter) and Cl- (129 meq/liter) concentrations in HL were significantly (P less than 0.01) higher than those in CL (Na+ = 148 meq/liter; Cl- = 120 meq/liter), in TD (Na+ = 146 meq/liter; Cl- = 121 meq/liter), and in RVP (Na+ = 144 meq/liter; Cl- = 114 meq/liter. These differences remained highly significant when the electrolyte concentrations were converted to milliequivalents per kilogram H2O. In contrast, no significant differences were detected between the concentrations of urea in the various fluids sampled. It is concluded that CL and HL do not drain a perfectly homogeneous intrarenal pool, and that they do not equilibrate with RVP or AP within the kidney. The results also indicate that CL and HL derive a small component from tubular reabsorbate; that for CL stemming from the cortex, and that for HL from the deeper cortex and outer medulla.

Effects of ischemia on forelimb weight and lymph protein concentration

The aim of this study was to determine if edema develops in the canine forelimb after relief of prolonged ischemia. Two hours of ischemia was induced either by interrupting brachial artery inflow in collateral-free innervated, naturally and constantly perfused preparations or by applying a pressure cuff in intact preparations. Changes in extravascular fluid volume were inferred from changes in limb weight. Relief of ischemia produced a transient 1.7% increase in weight in the collateral-free, naturally perfused preparation but had no effect on weight in the collateral-free, constantly perfused or intact preparations. Skin lymph flow failed to change significantly and total lymph protein concentration increased only slightly. Thus, relief of 2 hr of ischemia does not produce marked edema or a large increase in microvascular permeability to plasma proteins in the dog forelimb.

Cardiac lymph flow and composition in acute myocardial ischemia in dogs

Cardiac lymph was obtained from 12 normal dogs (group 1) for two consecutive 2-h control periods and from 7 dogs (group 2) for 2 h before and 2 h after occlusion of the circumflex branch of the left coronary artery. Lymph composition was studied with reference to pH, red blood cell (RBC) concentration, total protein content, potassium and sodium ion concentrations, and creatine phosphokinase (CPK) and acid phosphatase enzyme activities. No significant difference was noted in any variable between the two groups during the firts 2-h period. In group 1, no significant changes occurred in any variable as a result of the passage of time alone. In group 2, 2 h of myocardial ischemia produced increases of 53.3 plus or minus 5.1% in lymph flow, 67 plus or minus 5% in protein content, and 418 plus or minus 27% in the RBC concentration, suggesting increased blood capillary permeability. Lactate rose 120.5 plus or minus 27%, potassium concentration increased 16.9 plus or minus 2.4%, acid phosphatase increased 30 plus or minus 3%, and CPK rose 61.6 pluse or minus 10.9%, suggesting ischemic injury of myocardial cells. These changes in lymph were statistically significant (P LESS THAN 0.05) and reflect both capillary and myocardial cell abnormalities.

Effects of histamine and acetylcholine on equine digital lymph flow and composition

We measured the flow rate and protein concentration of lymph collected from a digital lymphatic in eight anesthetized ponies. Additionally, we recorded systemic arterial pressure (Part), and small vein pressure (Psv). Control lymph flow averaged 0.068 ml/min, and contained 3.11 g/100 ml of protein with albumin/globulin ratio of 0.75. Twenty-minute local intra-arterial infusion of acetylcholine (10 mug/min.) elevated Psv but did not increase lymph flow rate or protein concentration. A 60-min local intra-arterial infusion of histamine (10 mug/min) produced a marked sustained increase in Psv and both lymph flow and protein concentration. Edema developed in the digit receiving histamine. These data support the conclusion that in the horse, as in other species, histamine edema is due primarily to a decreased transcapillary colloid osmotic pressure gradient rather than an increased transcapillary hydrostatic pressure gradient.

Determination of extracellular fluid volume in the dog with ferrocyanide

The suitability of ferocyanide as an indicator for the measurement of extracellular fluid volume was tested. Added ferrocyanide could be recovered completely from urine, plasma and blood. In in vitro experiments ferrocyanide did not penetrate into erythrocytes, nor did it adhere to the red cell membrane. In gel filtration and electrophoresis experiments binding of ferrocyanide to plasma proteins could not be demonstrated. In in vivo experiments on dogs, the urinary recovery of intravenously administered ferrocyanide was 98.9 +/- 2.1% (n = 14). The partition ratio of ferrocyanide between lymph water and plasma water was 0.99 +/- 0.02 (n = 20). Ferrocyanide could not be detected in cerebrospinal fluid or red cells of dogs after administration by intravenous infusion. No untoward effects of the infused ferrocyanide were observed during or after the experiments. In nephrectomized dogs ferrocyanide reached its ultimate distribution volume 2 hrs after intravenous administration of a single dose and remained constant for up to 10 hrs. The average distribution volume was 224 +/- 17 ml-kg-1 body mass (n = 6). In intact dogs continuously infused with indicator, ferrocyanide also reached its ultimate distribution volume in 2 hrs and remained constant thereafter for up to 7 hrs after the start of the infusion. The average distribution volume was 237 +/- 27 ml-kg-1 body mass (n = 14). It is concluded that ferrocyanide fulfils the requirements to be met by an indicator for the measurement of the extracellular volume, and is well suited for repeated determinations of the extracellular fluid volume in one and the same experiment.

Bile constituents in blood and lymph during biliary obstruction. I. The dynamics of absorption and transport of ions and colloid molecules

Na125I and 131I-labeled albumin was infused in dogs into the common bile duct at pressures of 20 to 25 and 40 mmHg. At 40 mmHg, the amounts of the iodide ion and labeled albumin in circulating plasma were, after correction for the secondary loss from the circulation, nearly identical. At 20-25 mmHg more iodid than labeled albumin was found in the circulation. In thoracic duct lymph the same fraction of the infused amount of albumin was recovered at both pressures. Lymphatic concentrations of albumin were in both types of experiments substantially higher than plasma concentrations. It is concluded, that at increased pressure fluid leaks first from the small biliary ducts into the Mall's spaces. In consequence of water absorption and the diffusion of ions and small molecules into the blood capillaries the concentrations of protein or protein bound molecules in this part of the hepatic interstitial fluid increases. This is reflected in their high concentration in the lymph. If bile pressure rises further, fluid leaks also into the Disse's spaces. This leads to a bulk flow of solvent and solutes into the sinusoids and to the near disappearance of the differences in the venous transport of ions and colloids.