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Biomedical subjects

J B Hay

Publications and source records attributed to J B Hay.

At least 37 records · Page 2Linked to original sources
PubMed1996

The exit of lymphocytes and RBCs from the peritoneal cavity of sheep.

The purpose of this study was to compare the exit rates and migration pathways of 51Cr-labeled lymphocytes from the peritoneal cavity into the blood with those of a non-motile cell population, 111In-RBCs, in order to determine whether lymphocytes actively migrate from the peritoneal cavity. Radiolabeled cells were infused into the peritoneal cavity and multiple samples of lymph draining from the peritoneal cavity and/or blood were obtained, then the animal was sacrificed and various tissues were harvested and assayed for radioactivity. The recovery of 51Cr-lymphocytes from the mesenteric nodes was not significantly different from that of nodes anatomically distant from the cavity, so it is unlikely that large numbers of lymphocytes migrate across the mesothelial lining of the cavity and into the mesenteric lymphatics. However, the caudal mediastinal node contained about 18-fold more 51Cr-lymphocytes and 473 times as many 111In-RBCs, confirming the importance of this node in the drainage of cells and fluid from the cavity. The hepatic node also appears to receive cells directly from the peritoneal cavity. We also calculated the recovery of labeled cells at the end of the experiment (T = 40 h), and found that the recovery of 51Cr-lymphocytes (3.87 +/- 1.29% ID) in the blood was much lower than that of 111In-RBCs (35.28 +/- 5.02% ID). This difference can be attributed mainly to the traffic of labeled lymphocytes out of the blood rather than the selective retention of lymphocytes within the peritoneal cavity. Cannulation of the caudal mediastinal efferent lymphatic and the thoracic duct, which drain the peritoneal cavity, revealed approximately a 3-fold higher cumulative recovery of 111In-RBCs than 51Cr-lymphocytes over 6 h. However, by 40 h the percentage of labeled RBCs and lymphocytes remaining in the cavity was not significantly different. While 51Cr-lymphocytes may leave the peritoneal cavity at a slower rate than 111In-RBCs, both cell populations appear to exit solely via lymphatic vessels.

Animals↗
PubMed1996

Long-segment nerve allograft regeneration in the sheep model: experimental study and review of the literature.

Experimental work in the field of nerve allotransplantation has dealt with the feasibility of nerve allografts reconstructing nerve gaps. In the majority of studies, the nerve gap studied has been short, and some degree of regeneration has been achieved, even in the untreated allograft. To better approximate clinical nerve-allograft reconstruction, a series of long-segment (8-cm) nerve allografts were performed in the ovine model. Twenty outbred ewes were randomized into two experimental groups with four experimental conditions. Animals received nerve allografts treated under one of the following conditions: fresh nerve autograft, fresh nerve allograft, cold-preserved nerve autograft, or cold-preserved nerve allograft. The nerve grafts were examined and compared at 6 and 10 months, using histological, morphometric, and electro-physiologic analyses. The results of the study demonstrated that, while excellent regeneration occurred across the nerve autograft, the long nerve allograft could not support axonal elongation. Similarly, cold nerve preservation did not enhance regeneration. The sheep animal model allows for investigation of the long nerve gap and may be beneficial in a better correlation of experimental nerve transplantation with clinical conditions.

Animals↗
PubMed1996

Reduction in peripheral nerve allograft antigenicity with warm and cold temperature preservation.

Lymphocyte migration into fresh and preserved peripheral nerve allografts was assessed to determine the effects of preservation time, preservation temperature, and graft harvest technique on the immunologic response to the peripheral nerve allograft. Peroneal nerve was harvested from either live or cadaveric (tissue) donors and stored as 1.5-cm segments at 5 degrees C or 37 degrees C for 1, 3, 5, or 7 days. Each of nine outbred ewes then received multiple segments of peroneal autograft, fresh allograft, and preserved nerve allograft implants. Lymphocyte migration was studied 7 days after implantation by intravenous injection of autologous 111In-labeled lymphocytes and quantified by gamma counter. Lymphocyte migration into fresh allografts (7212 +/- 1575) increased an average of 4.1 times over fresh autograft tissue (1758 +/- 421; p < 0.05). Short-term preservation (24 hours) at both temperatures enhanced lymphocyte migration into pretreated allograft tissue (12684 +/- 2575 at 5 degrees C, 8751 +/- 1577 at 37 degrees C) as compared with fresh allograft (7212 +/- 1575). Conversely, 7 days of pretreatment at both 5 degrees C (3586 +/- 1421) and 37 degrees C (1570 +/- 414) resulted in migration values not significantly different from autograft. No statistically significant difference was seen between grafts harvested from live (5710 +/- 1651) versus cadaveric (tissue) donors (4013 +/- 832) after 5 days of cold preservation.

Analysis of Variance↗
PubMed1996

Lymph and interstitial fluid dynamics in labial gingival tissues of sheep.

Lymphatic drainage and circulation in periodontal tissues have been cited as important components of host defence and pathogenic mechanisms, but quantitative data are sparse because of the technical difficulties associated with small animal lymphatic studies. However, the lymphatic vessels draining the periodontal tissues and surrounding region are sufficiently large in sheep to permit surgical placement of lymphatic catheters. Consequently, lymph and recirculating lymphocytes can be continuously collected and this permits the quantitative assessment of local immune responses in these tissues. We have studied the lymphatic drainage pathways from the labial gingival tissues in sheep by two methods. First, in a series of anatomical studies (n = 6), a complex of Evan's blue dye and albumin was injected into the labial gingival tissues. One hour after injection the animals were sacrificed and the submandibular and cervical regions were dissected to expose the stained lymphatics. This anatomical study demonstrated 2 major drainage pathways: 1) cervical lymph ducts and; 2) efferent prescapular lymphatics. Secondly, to compare the relative importance of these two drainage pathways, radiolabeled protein (125I-albumin) was injected directly into the gingival tissues and its appearance in the cervical and prescapular lymph was measured (n = 7). Despite the technical difficulties encountered in the experiments, data collected showed that over 7.5 h, 64.7% of the injected protein was recovered in the prescapular and cervical lymph vessels (31.8 +/- 6.5% and 32.9 +/- 8.5%, respectively). In addition, 11.9 +/- 2.1% of the injected protein was transported to the blood by routes not involving the cannulated cervical and prescapular lymph vessels. With most of the remaining radiolabeled protein (17.9 +/- 4.9%) recovered from the injection site, we were able to account for approximately 95% of the injected protein. This study suggests that the lymph drainage from this region in the sheep model could provide one of the best described closed and contained systems and thus, could be a useful system for future continuous monitoring of inflammatory responses during experimental periodontal diseases.

Albumins↗
PubMed1995

Phenotypic analysis of migrant, efferent lymphocytes after implantation of cold preserved, peripheral nerve allografts.

Cold-preservation of peripheral nerve allografts in vitro (3 weeks, 5 degrees C) was performed to determine its effect on local lymphocyte migration patterns in vivo. Lymphocyte migration was assessed by continuously monitoring the cell output in the regional lymph for nearly 1 month. Cold-preservation delayed or prevented the typical biphasic increase in efferent lymphocyte output observed after fresh allograft implantation. It also decreased the output of activated lymphocytes (CD 5 and MHC class II positive) compared with that seen in the fresh allograft response. These changes suggest that the host immune response to preserved nerve allografts is altered over a prolonged period in vivo (3 weeks). Cold-preservation may be a useful method of reducing allograft immunogenicity, thereby limiting systemic immunosuppression requirements for the successful clinical utilization of peripheral nerve allografts.

Animals↗
PubMed1995

Rapid turnover of the recirculating lymphocyte pool in vivo.

Lymphocytes are unique among blood cells in their capacity to continually recirculate between blood and the tissues via the lymph. Previous estimates of lymphocyte lifespan in vivo and the turnover of the recirculating lymphocyte pool have been deduced from indirect labeling techniques. Using the fluorescent dye PKH-26, individual labeled cells have been tracked in sheep for periods > 2 months. By direct measurement their lifespan was calculated. This label was found to be stable in vivo, allowing long-term analysis of the characteristics of the recirculating lymphocyte pool. It is possible to calculate the rate of turnover of cells of the recirculating pool based on the rate at which labeled cells disappear from the lymphatic circulation. The recirculating lymphocyte pool was found to repopulate itself every 16.5 +/- 3.0 days. Using this label, it was estimated that recirculating lymphocytes divide on average once every 29.8 +/- 6.8 days. Labeled erythrocytes were also examined and found to have an average lifespan of 153 days, demonstrating no dye loss over the 2 month period of observation. These data suggest that the recirculating lymphocyte pool is a highly dynamic compartment, with a high rate of turnover and peripheral cell division in vivo. This is the first report of the direct measurement of the in vivo turnover of recirculating lymphocyte pools, and this method may now be used to further analyze the lifespan of individual lymphocyte subsets and the in vivo lifespan of other cell types in vivo.

Animals↗
PubMed1995

Repeated exposure to silicone gel can induce delayed hypersensitivity.

The possible immunologic reactivity of silicone gel remains speculative and controversial. In this laboratory, a quantitative lymphocyte localization assay has been developed and well studied using pure lymphocytes collected by the technique of lymph vessel cannulation in sheep. The kinetics of antigen-specific immune responses (e.g., tuberculin reaction) in this model are well described and accepted. Using the known parameters regarding the response to purified protein derivative and the classic adjuvant Freund's Complete Adjuvant, this study was designed to identify the possible antigen-specific immunologic response, in the form of delayed-type hypersensitivity, after repeated exposure to silicone gel. Pure lymphocytes were collected by cannulating the efferent vessel of a subcutaneous lymph node in four groups of primed sheep which, 30 days previously, had received intradermal injections of 0.9% saline (negative controls; n = 6), Freund's Complete Adjuvant only (positive controls; n = 6), silicone gel (n = 7), or Freund's Complete Adjuvant homogenized with silicone gel (n = 7) in an attempt to induce sensitization. Multiple (1040) intradermal skin tests were performed using silicone gel, purified protein derivative, and 0.9% saline. After the skin lesions had developed for 48 hours, 5 x 10(8) lymphocytes were labeled in vitro with indium-111, returned intravenously, and allowed to circulate for 3 hours. Sheep were euthanized, the skin lesions were removed, and the radioactivity was counted in a gamma spectrometer. The radioactivity in each skin lesion is considered a measure of lymphocyte accumulation. The occurrence of augmented accumulation after reexposure to an antigen is a hallmark of delayed-type hypersensitivity. The purified protein derivative and saline lesions functioned as positive and negative controls, with counts per minute (cpm +/- standard error) of 2404 +/- 478 (Freund's Complete Adjuvant group) and 149 +/- 21 (saline group), respectively. Significantly greater (p = 0.0021) radioactivity was found in the silicone gel sites (310 +/- 35) in the silicone gel-primed group and the Freund's Complete Adjuvant plus silicone gel group (453 +/- 44; p = 0.0004) than in normal skin in each group. These data suggest that it may be possible to induce an antigen-specific lymphocyte-mediated response to silicone gel.

Animals↗
PubMed1994

Blood-to-lymph migration of small lymphocytes through the liver of the sheep.

The process of lymphocyte migration is required for the systemic dissemination of immunological memory and immune surveillance. We report here experiments to quantitate the normal traffic of lymphocytes that occurs from blood to lymph through the liver and hepatic node in the sheep. Comparisons were made with known lymphocyte homing pools. Individual afferent hepatic lymphatics had cell outputs of 1.4 +/- 0.1 x 10(6) cells/hr, suggesting that the total combined lymphocyte output from the liver was no greater than about 1 x 10(7) cells/hr. The lymphocyte output in efferent hepatic lymph was 6.2 +/- 0.4 x 10(7) cells/hr, comparable to the cell outputs recorded from other lymph nodes of similar size. When the specificity of lymphocytes homing through the liver or hepatic node was examined, we found similarities to both the peripheral lymph node and intestinal lymph node homing patterns. Migration into afferent hepatic lymph was found to be different from that into intestinal or subcutaneous efferent lymph, and the kinetics of migration into hepatic afferent lymph was faster than that observed into efferent compartments. Intravenously injected endotoxin was found to alter the normal lymph flow through the liver tissue and the hepatic node; it appeared to enhance the migration of macrophages out of the liver by way of the afferent lymph. These studies suggest unique features of lymphocyte traffic through the liver and the need for further experiments on hepatic lymphocyte traffic, particularly in pathological states with substantial mononuclear cell infiltration.

Animals↗
PubMed1994

Effect of phosphatidylcholine on lymphatic drainage and fluid loss from the peritoneal cavity of sheep.

The purpose of this investigation was to test the hypothesis that phosphatidylcholine enhances net ultrafiltration by decreasing lymphatic drainage of the peritoneal cavity. Twelve sheep were used in this study. Six animals received 50 ml/kg intraperitoneal infusions of Dianeal 4.25% (490 mOsm/liter) and six received similar volumes of premixed phosphatidylcholine-Dianeal (510 mOsm/liter). Labeled albumin (25 microCi 125I-human serum albumin) was added to the dialysate as a lymph flow marker. Lymph drainage of the peritoneal cavity was estimated from the appearance of the intraperitoneally administered tracer in the blood. Net ultrafiltration was significantly enhanced by phosphatidylcholine at each hour up to 6 hours post-infusion, and over this period reached 30.3 +/- 3.8 ml/kg in the phosphatidylcholine animals compared to 12.2 +/- 2.1 ml/kg in the control group. Phosphatidylcholine treatment decreased the volume removed by lymphatics; by six hours 5.5 +/- 1.1 ml/kg in the animals receiving phosphatidylcholine, and 10.3 +/- 1.0 ml/kg in the control group was drained as lymph. Fluid loss (estimated from the tracer disappearance from the peritoneal cavity) was slightly less in the phosphatidylcholine-treated animals, averaging 15.8 +/- 1.6 in this group versus 16.8 +/- 1.7 ml/kg in the control sheep. However, these differences were not significant. Phosphatidylcholine significantly increased transcapillary ultrafiltration (estimate of volume movement into peritoneal cavity without fluid loss) from 27.6 +/- 1.5 ml/kg in the controls to 43.8 +/- 3.4 ml/kg in the animals receiving phosphatidylcholine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

51Cr-RBCs and 125I-albumin as markers to estimate lymph drainage of the peritoneal cavity in sheep.

The purpose of this study was to compare the use of 125I-labeled human serum albumin (125I-HSA) and autologous 51Cr-labeled red blood cells (51Cr-RBCs) as lymph flow markers to estimate lymph drainage of the peritoneal cavity in conscious sheep. In one group, we assessed lymph drainage from the appearance of intraperitoneally administered tracer in the bloodstream. To determine distribution of drainage into discrete lymph compartments, in a second group of studies, lymph was collected from the caudal mediastinal lymph node and the thoracic duct, both of which are involved in lymphatic drainage of the ovine peritoneal cavity. Ringer lactate solution (50 ml/kg) containing 8-10 microCi each of 125I-HSA and 51Cr-RBCs was infused into the peritoneal cavity. Lymph drainage was calculated by dividing the change in mass of tracer in the blood or lymph compartments by the average intraperitoneal tracer concentration. In noncannulated animals, lymph drainage averaged over 6 h was higher with 125I-HSA as tracer (1.35 +/- 0.12 vs. 0.62 +/- 0.19 ml.h-1.kg-1 with 51Cr-RBCs). A similar pattern was noted in terms of drainage into the caudal lymphatic (0.89 +/- 0.23 and 0.52 +/- 0.19 ml.h-1.kg-1 with 125I-HSA and 51Cr-RBCs, respectively) and thoracic duct (0.16 +/- 0.06 and 0.05 +/- 0.02 ml.h-1.kg-1 with 125I-HSA and 51Cr-RBCs, respectively). Analysis of 125I-HSA and 51Cr-RBC concentrations in lymph and intraperitoneal fluid suggested sieving of RBCs at the diaphragmatic stomata or lymph nodes. Using 125I-HSA as tracer and combining data from noncannulated and cannulated sheep, we estimated peritoneal lymph drainage to be 1.35 ml.h-1.kg-1, with 66% of this flow drained by the caudal vessel, 22% by the parasternal pathway (right lymph duct), and 12% by the thoracic duct.

Animals↗
PubMed1994

Lymph flow and lymphatic drainage of inflammatory cells from the peritoneal cavity in a casein-peritonitis model in sheep.

The purpose of this study was to characterize the cellular responses in the peritoneal cavity and draining lymph in a sterile peritonitis model in conscious sheep. Lymph was collected from lymphatics that drained the peritoneal space (caudal mediastinal and thoracic ducts) as well as from lymph vessels that drained peripheral tissues (prescapular). Casein was used as the inflammatory agent. Dialysis solution (Dianeal 4.25%) containing 1g% casein and 25 microCi 125I-human serum albumin was infused into the peritoneal cavity in 50 ml/kg volumes. Peritoneal volumes increased from a mean infused volume of 1572 +/- 51 ml to a maximum of 2119 +/- 77 ml at 3 hours. Over 6 hours, the number of macrophages and lymphocytes in the peritoneal cavity remained relatively constant but the number of neutrophils increased from 9.9 +/- 4.2 x 10(7) to 9.2 +/- 1.9 x 10(9) total cells. Caudal lymph which drains directly from the peritoneal cavity through diaphragmatic stomata, demonstrated a 5 fold increase in flow rate over 6 hours following the Dianeal-casein infusion. Thoracic duct and prescapular flows declined approximately 70% and 50% respectively in the same time period. the concentration of lymphocytes and the lymphocyte outputs (product of volume and concentration) declined in all lymph compartments. No elevations in neutrophil numbers in the thoracic and prescapular lymph compartments were observed but neutrophil output in the caudal lymph increased steadily from 3.1 +/- 1.5 x 10(6) to 4.6 +/- 1.3 x 10(7)/hr at the 6 hour mark. We conclude that the major route of removal of inflammatory cells and fluid from the peritoneal cavity is through diaphragmatic lymphatics.

Animals↗
PubMed1994

Characterization of ovine lymphatic endothelial cells and their interactions with lymphocytes.

The interaction of blood-borne lymphocytes with blood vascular endothelial cells is a fundamental component of lymphocyte circulation. The role of lymphatic endothelial cells is less certain. These studies describe the isolation, characterization and lymphocyte binding capacity of efferent lymphatic endothelial cells from ovine mesenteric lymphatic vessels. Lymphatic endothelial cells had anti-thrombin 3, von Willebrand Factor and MHC I on their surface. The cells also actively metabolized acetylated low density lipoprotein. The morphological appearance was indistinguishable from blood vascular endothelium but quite different from cultured smooth muscle cells. Lymphocyte binding to lymphatic endothelial cells was not significantly different from binding to carotid artery or jugular vein endothelial cells. The degree of binding in all cases could be enhanced by incubating endothelial cells in medium containing rh TNF-alpha (recombinant human tumor necrosis factor alpha).

Acetylation↗
PubMed1993

Lymphocyte recirculation and life span in vivo.

The physiological process of lymphocyte migration is a complex and dynamic process. The differential migration and life span of lymphocyte subsets is inherent to the normal function of the mammalian immune system. Adequate assessment of the involved processes requires the presence of an intact blood and lymphatic circulatory system and the ability to isolate individual tissues. The sheep provides an invaluable experimental model for studying these processes. Recent data suggest that direct quantitation of the life span of individual subsets of recirculating memory and naive lymphocytes is now possible, and that the long-term characterization of the behaviour of recirculating cells can be undertaken. Finally, it appears that previous qualitative data on tissue-specific homing pools can now begin to be understood in the context of phenotypic analysis for T cell markers and adhesion molecules, combined with long-term tracking techniques.

Animals↗
PubMed1993

Effect of cold preservation on lymphocyte migration into peripheral nerve allografts in sheep.

Lymphocyte migration into fresh and preserved peripheral nerve allografts was quantitated to assess the effect of cold preservation and freeze-thawing pretreatment on the local immunological response to nerve allografts. Out-bred ewes received multiple 1.5-cm subcutaneous heterotopic peroneal nerve autografts, fresh allografts, and pretreated allografts, implanted within the same recipient. Lymphocyte migration was studied at 7 days by injecting autologous 111indium-labeled lymphocytes intravenously. After 3 hr of recirculation, lymphocyte migration into graft tissue was quantitated by a gamma counter (epm/g, mean +/- SEM). Lymphocyte traffic into fresh nerve allografts (21,623 +/- 3783) increased an average 9.4-fold over the autograft value (2918 +/- 377, P < 0.04). Histologic studies illustrated a marked lymphocytic infiltrate of CD4+ and CD8+ cells and enhanced class I and II MHC expression in fresh allografts, but not in autografts. Short-term cold preservation, for 6 and 12 hr (5 degrees C), enhanced lymphocyte entry into pretreated allograft tissue. Conversely, cold preservation for longer periods (1 and 3 weeks) dramatically reduced lymphocyte migration to values below corresponding autograft levels (783 +/- 100 and 1,252 +/- 120, respectively, P < 0.01). A comparable reduction in lymphocyte migration into nerve allografts was observed after freeze-thawing pretreatment (P < 0.01). Cold preservation of donor allogeneic lymphocytes inhibited their capacity to induce intradermal host lymphocyte migration, implicating passenger lymphocytes as a potential cold-sensitive allogeneic component of the nerve allograft. Assessment of the local response to ovine peripheral nerve allografts, utilizing radiolabeled autologous lymphocytes, demonstrated that cold preservation and freeze-thawing pretreatment significantly reduced lymphocyte migration into nerve allografts. The mechanism(s) of reduced lymphocyte migration may involve inactivation or death of antigen-presenting cells, including passenger lymphocytes.

Animals↗
PubMed1993

Lymphatic drainage of hypertonic solution from peritoneal cavity of anesthetized and conscious sheep.

Lymphatic drainage of the peritoneal cavity may reduce ultrafiltration in continuous ambulatory peritoneal dialysis. We assessed lymphatic drainage of the peritoneal cavity in sheep under dialysis conditions by cannulation of the relevant lymphatic vessels and compared lymphatic drainage in anesthetized and conscious animals. Lymph was collected from the caudal mediastinal lymph node and the thoracic duct, both of which are involved in the lymphatic drainage of the ovine peritoneal cavity. Volumes of a hypertonic dialysis solution (50 ml/kg 4.25% Dianeal) containing 25 microCi 125I-human serum albumin were instilled into the peritoneal cavity, and lymph flows and the appearance of labeled protein in the lymphatic and vascular compartments were monitored for 6 h. Intraperitoneal pressures increased 4-5 cmH2O above resting levels after infusion of dialysate. On the basis of the appearance of tracer in the lymph, drainage of peritoneal fluid into the caudal lymphatic was calculated to be 3.09 +/- 0.69 and 14.14 +/- 2.86 ml/h in anesthetized and conscious sheep, respectively. Drainage of peritoneal fluid into the thoracic duct preparations was calculated to be 1.32 +/- 0.33 and 14.69 +/- 5.73 ml/h in anesthetized and conscious sheep, respectively. Significant radioactivity was found in the bloodstream, and at least a portion of this was likely contributed by the right lymph duct, which was not cannulated in our experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1993

Quantitation of lymphatic drainage of the peritoneal cavity in sheep: comparison of direct cannulation techniques with indirect methods to estimate lymph flow.

OBJECTIVE: It has been suggested that lymphatics may contribute to ultrafiltration failure in patients on continuous ambulatory peritoneal dialysis (CAPD) by absorbing dialysate and ultrafiltrate from the peritoneal cavity. In most studies lymphatic drainage has been estimated from the disappearance of an instilled tracer from the peritoneal cavity or estimated from the appearance of an intraperitoneally administered tracer in the bloodstream. However, in sheep it is possible to cannulate several of the relevant lymphatics that drain the peritoneal cavity and assess lymph drainage parameters directly. The purpose of this study was to estimate lymph drainage from the peritoneal cavity in sheep using the disappearance of tracer from the cavity and the appearance of intraperitoneally instilled tracer in the bloodstream and to compare these results with those obtained from our previous studies using cannulation techniques. DESIGN: Experiments were performed in anesthetized and nonanesthetized animals. Volumes of 50 mL/kg of Dianeal 4.25% containing 25 microCi of 125I-albumin were infused into the peritoneal cavity. RESULTS: In anesthetized sheep the calculated peritoneal lymph drainage from monitoring the disappearance of tracer from the peritoneal cavity over 6 hours was 1.873 +/- 0.364 mL/kg/hour. Monitoring the appearance of tracer in the blood gave significantly lower peritoneal lymph flow rates of 1.094 +/- 0.241 mL/kg/hour. Directly measured lymph flow rates from our earlier publication were lower still and ranged from 0.156 +/- 0.028-0.265 +/- 0.049 mL/hour/kg, depending on how we estimated the right lymph duct contribution to peritoneal drainage, since we could not cannulate this vessel. We repeated these experiments in conscious sheep. The value for lymph flow estimated from the disappearance of tracer from the peritoneal cavity was 2.398 +/- 0.617 mL/hour/kg and from the appearance of tracer in the blood, 1.424 +/- 0.113 mL/hour/kg. The lymph flow rates monitored from indwelling lymphatic catheters ranged from 1.021 +/- 0.186-1.523 +/- 0.213 mL/hour/kg (again, depending on our estimates for the right lymph duct). CONCLUSIONS: Lymph flow rates measured from indwelling lymphatic catheters provided the most conservative values for lymphatic drainage of the peritoneal cavity under dialysis conditions. Estimates of lymphatic drainage based on the appearance of tracer in the blood gave values that were on average higher. The method using the disappearance of tracer from the cavity to estimate lymph flows overestimated peritoneal lymph drainage. Fluid was lost from the peritoneal cavity, and the estimated proportion of liquid lost through lymphatic drainage depended on the technique used to measure lymph flow rates.

Absorption↗