Lymph and pulmonary response to isobaric reduction in plasma oncotic pressure in baboons. (1/833)

Plasma colloid osmotic pressure was reduced by 76% (from 19.6 +/- 0.6 to 4.7 +/- 1.5 mm Hg) in five baboons while pulmonary capillary hydrostatic pressure was maintained at a normal level. This resulted in fluid retention, weight gain, peripheral edema and ascites, but no pulmonary edema. Thoracic duct lymph flow increased 6-fold and pulmonary lymph flow 7-fold. Thoracic duct lymph had a lower colloid osmotic pressure (2.0 +/- 0.7 mm Hg) than plasma (4.7 +/- 1.5 mm Hg), whereas the colloid osmotic pressure of pulmonary lymph (4.7 +/- 0.7 mm Hg) was the same as that of plasma. The lymph-plasma ratio for albumin fell in thoracic duct lymph but remained unchanged in pulmonary lymph. The difference between plasma colloid osmotic pressure and pulmonary artery wedge pressure decreased from 15.3 +/- 1.9 to -0.7 +/- 2.9 mm Hg. Despite this increase in filtration force, the lungs were protected from edema formation by a decrease of 11 mm Hg in pulmonary interstitial colloid osmotic pressure and a 7-fold increase in lymph flow.  (+info)

An isolated perfused rat lung preparation. (2/833)

An isolated perfused rat lung preparation (IPL) is described and its physiologic status is evaluated. The evaluation includes light and electron microscopy after perfusion and estimations of substrate utilization. ATP content, lactate production, and incorporation of glucose carbons into lipids and CO2. It is concluded that the IPL is useful for short-term metabolic and physiologic experiments and offers some unique advantages in evaluating effects of reactive gases upon lung function.  (+info)

Role of L-selectin in physiological manifestations after burn and smoke inhalation injury in sheep. (3/833)

The effects of a monoclonal antibody against L-selectin [leukocyte adhesion molecule (LAM)1-3] on microvascular fluid flux were determined in conscious sheep subjected to a combined injury of 40% third-degree burn and smoke inhalation. This combined injury induced a rapid increase in systemic prefemoral lymph flow (sQlymph) from the burned area and a delayed-onset increase in lung lymph flow. The initial increase in sQlymph was associated with an elevation of the lymph-to-plasma oncotic pressure ratio; consequently, it leads to a predominant increase in the systemic soft tissue permeability index (sPI). In an untreated control group, the increased sPI was sustained beyond 24 h after injury. Pretreatment with LAM1-3 resulted in earlier recovery from the increased sPI, although the initial responses in sQlymph and sPI were identical to those in the nontreatment group. The delayed-onset lung permeability changes were significantly attenuated by pretreatment with LAM1-3. These findings indicate that both leukocyte-dependent and -independent mechanisms are involved in the pathogenesis that occurs after combined injury with burn and smoke inhalation.  (+info)

Transport of colloidal particles in lymphatics and vasculature after subcutaneous injection. (4/833)

This study was designed to determine the transport of subcutaneously injected viral-size colloid particles into the lymph and the vascular system in the hind leg of the dog. Transport of two colloid particles, with average size approximately 1 and 0.41 microm, respectively, and with and without leg rotation, was tested. Leg rotation serves to enhance the lymph flow rates. The right femoral vein, lymph vessel, and left femoral artery were cannulated while the animal was under anesthesia, and samples were collected at regular intervals after subcutaneous injection of the particles at the right knee level. The number of particles in the samples were counted under fluorescence microscopy by using a hemocytometer. With and without leg rotation, both particle sets were rapidly taken up into the venous blood and into the lymph fluid. The number of particles carried away from the injection site within the first 5 min was <5% of the injected pool. Particles were also seen in arterial blood samples; this suggests reflow and a prolonged residence time in the blood. These results show that particles the size of viruses are rapidly taken up into the lymphatics and blood vessels after subcutaneous deposition.  (+info)

Human follicular dendritic cells remain uninfected and capture human immunodeficiency virus type 1 through CD54-CD11a interaction. (5/833)

It has been reported that human immunodeficiency virus type 1 (HIV-1) bound to follicular dendritic cells (FDCs) remains highly infectious to CD4(+) T cells even when it forms immune complexes with neutralizing antibody (HIV-1/IC). To elucidate the role of FDCs in HIV-1 transmission to CD4(+) T cells in lymph nodes, we have isolated and purified FDCs from human tonsils and examined whether the HIV-1/IC trapped on their surface is infectious to CD4(+) T cells. To our surprise, not the HIV-1/IC but the antibody-free HIV-1 on FDCs could be transmitted to CD4(+) T cells. Furthermore, in contrast to previous studies showing that FDCs are productively infected with HIV-1, the present study clearly demonstrated that FDCs were not the target cells for HIV-1 infection. FDCs could capture the viral particles on their surface; however, the binding of HIV-1 to FDCs was strongly inhibited by the presence of anti-CD54 (ICAM-1) monoclonal antibody (MAb) and anti-CD11a (LFA-1) MAb, suggesting that the adhesion molecules play an important role in the interaction between HIV-1 and FDCs.  (+info)

Intracerebroventricular injection of TNF-alpha promotes sleep and is recovered in cervical lymph. (6/833)

Recent studies have shown that the central nervous system (CNS) communicates with the periphery by the drainage of cerebrospinal fluid and brain interstitial fluid into blood and lymph. We hypothesized that tumor necrosis factor (TNF)-alpha would not only influence the CNS by promoting sleep but also would be directly transmitted into the peripheral immune system. Five hundred nanograms of 125I-labeled TNF-alpha were injected into the lateral ventricles of the brain of six sheep and sampled in venous blood and cervical and prescapular lymph every 30 min for 6 h. 125I-TNF-alpha was measured in lymph nodes and control fat, skin, and muscle tissues 6 h postinjection. 125I-TNF-alpha was detected in the cervical lymphatics within the first 30 min and peaked within 2-3 h. 125I-TNF-alpha counts were elevated in the nodes of the head and neck region. Polysomnographic recordings of four animals showed that TNF-alpha induced a significant increase in slow-wave sleep at postinjection hours 4 and 5. CNS TNF-alpha and its direct drainage into the lymphatic system may influence both the sleeping/waking brain and peripheral immune functions.  (+info)

The standard peritoneal permeability analysis in the rabbit: a longitudinal model for peritoneal dialysis. (7/833)

OBJECTIVE: The development of an experimental peritoneal dialysis (PD) model in rabbits to investigate peritoneal transport characteristics during a longitudinal follow-up and to assess normal values of these peritoneal transport parameters. DESIGN: Peritoneal transport parameters were determined in conscious, unrestrained rabbits by standard peritoneal permeability analysis adjusted for rabbits (SPAR). In this test a 1-hour dwell with 3.86% glucose dialysate is used. Dextran 70 (1g/L) was added to the dialysate to allow calculation of fluid kinetics. Dialysate samples were taken before, 10, and 40 minutes after instillation and at the end of the dwell. Blood was drawn at the end of the dwell. EXPERIMENTAL ANIMALS: Eighteen female New Zealand White rabbits (2565 g) were included for catheter implantation. SPARs were performed in 15 animals; the other 3 were excluded due to complications. MAIN OUTCOME: The mass transfer area coefficients (MTACs) of the low molecular weight solutes urea (MTAC(urea)) and creatinine (MTACcr) were calculated. The clearances of albumin (CIalb) and IgG (CI(IgG)), glucose absorption, and fluid transport were computed. Coefficients of intraindividual variation (Vc) were calculated for these parameters. RESULTS: The main complications were catheter obstruction and/or dislocation. Five rabbits underwent uncomplicated PD during a 4-week period. Fifteen SPARs in 15 stable rabbits were performed and analyzed to obtain normal values. Means and standard deviations of the transport parameters were as follows: MTAC(urea) 2.24+/-0.57 mL/min, MTACcr 1.61+/-0.30 mU/min, CI(alb) 52.9+/-17.2 microL/min, CI(IgG) 44.5+/-22.9 UL/min. The transcapillary ultrafiltration rate was 0.66+/-0.13 mL/min and the lymphatic absorption rate 0.47+/-0.26 mL/min. The parameters of solute transport were upscaled to those in humans using two different methods. MTACs of low molecular weight solutes in rabbits and patients were of the same order of magnitude, but the clearance of albumin was approximately four times higher in rabbits than in patients, and that of IgG eight times. In all rabbits sieving of sodium was observed. The dialysate/plasma (D/P) of sodium decreased to a minimum at 40 min (p<0.003 vs the initial value), followed by a rise to 60 min. The minimal value was 0.884+/-0.002. The coefficients of variation calculated on 7 rabbits that underwent two or more SPARs were similar to those assessed from the patient data. This indicates stability of the model and reproducibility of the SPAR. CONCLUSION: The conscious rabbit model for PD can be used for repeated studies on peritoneal transport.  (+info)

Contamination of lymph from the major prenodal cardiac lymphatic in dogs. (8/833)

Cannulation of the canine major prenodal cardiac lymphatic (MPCL) is the most common approach for the investigation of myocardial lymphatic function. However, the assumption that the MPCL drains pure cardiac lymph has been questioned. We studied variations of MPCL anatomy and investigated whether noncardiac lymph is drained by this lymphatic. After dye was injected into the lungs and left ventricular myocardium in 21 dogs, dissection of the cardiac lymphatic system yielded 3 anatomic variations. In variations 1 and 2 (81% of dogs), a mixture of cardiac and pulmonary lymph was drained via the MPCL. In variation 3 (19% of dogs) no connection was found between MPCL and pulmonary lymphatics. In variations 1 and 2, alteration of tidal volume resulted in significant changes of lymph flow rate. The pulmonary contribution to MPCL lymph flow was estimated as 34% in variation 2. We conclude that MPCL lymph may contain not only cardiac lymph but also significant pulmonary contamination. This finding should be considered in the interpretation of lymph data from cannulation of the canine MPCL.  (+info)