Caudal Mediastinal Node Research Articles

Динаміки вагових характеристик лімфатичних вузлів великої рогатої худоби в пренатальному періоді онтогенезу

In lymph nodes, as peripheral organs of the immune system, the patterns of their growth and development are unique in many ways, especially during the prenatal period of ontogenesis. The changes in the absolute and relative mass of lymph nodes in 66 bovine fetuses of different gestational ages (2–9 months) were studied. The weight of the fetuses and organs was determined with an accuracy of 0.001 g. According to the indicators of weight, body length, and the degree of development of the fetal skin derivatives, their age was established. It was found that in the first third of the fetal period of ontogenesis, the dynamics of the lymph nodes’ absolute mass was characterized by a moderate increase, which occurred simultaneously with an increase in the weight of the fetus itself. The relative weight at the beginning of the fetal period changed unevenly: it decreased in the superficial cervical and mandibular and increased in the popliteal and caudal mediastinal lymph nodes. In the second third of the fetal period, both the absolute and the relative weight of the examined organs increased dramatically (with the maximum at 7 months-old age). During the last third of the fetal period, a gradual increase in the absolute mass of all lymph nodes was found, and their relative mass, on the contrary, decreased moderately. In the second and last third of prenatal development, there was no direct relationship between the growth of the lymph nodes mass and the fetal total mass.

KLF2-mediated disruption of PPAR-γ signaling in lymphatic endothelial cells exposed to chronically increased pulmonary lymph flow.

Lymphatic abnormalities associated with congenital heart disease are well described, yet the underlying mechanisms remain poorly understood. Using a clinically relevant ovine model of congenital heart disease with increased pulmonary blood flow, we have previously demonstrated that lymphatic endothelial cells (LECs) exposed in vivo to chronically increased pulmonary lymph flow accumulate ROS and have decreased bioavailable nitric oxide (NO). Peroxisome proliferator-activated receptor-γ (PPAR-γ), which abrogates production of cellular ROS by NADPH oxidase, is inhibited by Krüppel-like factor 2 (KLF2), a flow-induced transcription factor. We hypothesized that chronically increased pulmonary lymph flow induces a KLF2-mediated decrease in PPAR-γ and an accumulation of cellular ROS, contributing to decreased bioavailable NO in LECs. To better understand the mechanisms that transduce the abnormal mechanical forces associated with chronically increased pulmonary lymph flow, LECs were isolated from the efferent vessel of the caudal mediastinal lymph node of control ( n = 5) and shunt ( n = 5) lambs. KLF2 mRNA and protein were significantly increased in shunt compared with control LECs, and PPAR-γ mRNA and protein were significantly decreased. In control LECs exposed to shear forces in vitro, we found similar alterations to KLF2 and PPAR-γ expression. In shunt LECs, NADPH oxidase subunit expression was increased, and bioavailable NO was significantly lower. Transfection of shunt LECs with KLF2 siRNA normalized PPAR-γ, ROS, and bioavailable NO. Conversely, pharmacological inhibition of PPAR-γ in control LECs increased ROS equivalent to levels in shunt LECs at baseline. Taken together, these data suggest that one mechanism by which NO-mediated lymphatic function is disrupted after chronic exposure to increased pulmonary lymph flow is through altered KLF2-dependent PPAR-γ signaling, resulting in increased NADPH oxidase activity, accumulation of ROS, and decreased bioavailable NO. NEW & NOTEWORTHY Lymphatic endothelial cells, when exposed in vivo to chronically elevated pulmonary lymph flow in a model of congenital heart disease with increased pulmonary blood flow, demonstrate Krüppel-like factor 2-dependent disrupted peroxisome proliferator-activated receptor-γ signaling that results in the accumulation of reactive oxygen species and decreased bioavailable nitric oxide.

Differential Cytokine Gene Expression in Granulomas from Lungs and Lymph Nodes of Cattle Experimentally Infected with Aerosolized Mycobacterium bovis.

The hallmark lesion of tuberculosis in humans and animals is the granuloma. The granuloma represents a distinct host cellular immune response composed of epithelioid macrophages, lymphocytes, and multinucleated giant cells, often surrounding a caseous necrotic core. Within the granuloma, host-pathogen interactions determine disease outcome. Factors within the granulomas such as cytokines and chemokines drive cell recruitment, activity, function and ultimately the success or failure of the host’s ability to control infection. Hence, an understanding of the granuloma-level cytokine response is necessary to understand tuberculosis pathogenesis. In-situ cytokine expression patterns were measured using a novel in situ hybridization assay, known as RNAScope® in granulomas of the lungs, tracheobronchial lymph nodes and caudal mediastinal lymph nodes of cattle experimentally infected with Mycobacterium bovis via aerosol exposure. In spite of microscopic morphological similarities, significant differences were seen between late stage granulomas of the lung compared to those of the tracheobronchial lymph nodes for IL-17A, IFN-γ, TGF-β, IL10 and IL-22 but not for TNF-α. Additionally, significant differences were noted between granulomas from two different thoracic lymph nodes that both receive afferent lymphatics from the lungs (i.e., tracheobronchial and caudal mediastinal lymph nodes) for TNF-α, IL-17A, IFN-γ, TGF-β and IL-10 but not for IL-22. These findings show that granuloma morphology alone is not a reliable indicator of granuloma function as granulomas of similar morphologies can have disparate cytokine expression patterns. Moreover, anatomically distinct lymph nodes (tracheobronchial vs caudal mediastinal) differ in cytokine expression patterns even when both receive afferent lymphatics from a lung containing tuberculoid granulomas. These findings show that selection of tissue and anatomic location are critical factors in assessing host immune response to M. bovis and should be considered carefully.

Disrupted NOS signaling in lymphatic endothelial cells exposed to chronically increased pulmonary lymph flow.

Associated abnormalities of the lymphatic circulation are well described in congenital heart disease. However, their mechanisms remain poorly elucidated. Using a clinically relevant ovine model of a congenital cardiac defect with chronically increased pulmonary blood flow (shunt), we previously demonstrated that exposure to chronically elevated pulmonary lymph flow is associated with: 1) decreased bioavailable nitric oxide (NO) in pulmonary lymph; and 2) attenuated endothelium-dependent relaxation of thoracic duct rings, suggesting disrupted lymphatic endothelial NO signaling in shunt lambs. To further elucidate the mechanisms responsible for this altered NO signaling, primary lymphatic endothelial cells (LECs) were isolated from the efferent lymphatic of the caudal mediastinal node in 4-wk-old control and shunt lambs. We found that shunt LECs (n = 3) had decreased bioavailable NO and decreased endothelial nitric oxide synthase (eNOS) mRNA and protein expression compared with control LECs (n = 3). eNOS activity was also low in shunt LECs, but, interestingly, inducible nitric oxide synthase (iNOS) expression and activity were increased in shunt LECs, as were total cellular nitration, including eNOS-specific nitration, and accumulation of reactive oxygen species (ROS). Pharmacological inhibition of iNOS reduced ROS in shunt LECs to levels measured in control LECs. These data support the conclusion that NOS signaling is disrupted in the lymphatic endothelium of lambs exposed to chronically increased pulmonary blood and lymph flow and may contribute to decreased pulmonary lymphatic bioavailable NO.

Detection of Jaagsiekte sheep retrovirus in apparently healthy sheep by real-time TaqMan PCR in comparison with histopathological findings

Abstract Introduction: The aim of this study was to use TaqMan real-time PCR technique to investigate Jaagsiekte sheep retrovirus (JSRV) proviral DNA in whole blood samples of sheep, and compare the results to those of histopathological examinations. Material and Methods: Eighty blood samples from clinically healthy sheep were randomly collected before the animals were slaughtered. Ten tissue samples from each lung and associated caudal mediastinal lymph node were taken. Results: Fifteen (18.75%) blood samples were found to contain proviral DNA, and 11 (13.75%) corresponding lung samples showed microscopic changes consistent with ovine pulmonary adenocarcinoma. None of the samples displayed metastases to the caudal mediastinal lymph nodes. The prominent pattern of neoplastic nodules consisted of acinar (alveolar) form. Conclusion: The results indicated the higher sensitivity of real-time PCR compared to histopathological examinations in detection of ovine pulmonary adenocarcinoma.

Zygomycotic Mediastinal Lymphadenitis in Beef Cattle with Ruminal Tympany

ABSTRACTA 9-month-old steer was autopsied due to recurrent ruminal tympany. A macroscopic examination found an enlarged caudal mediastinal lymph node, and a section of the lymph node revealed necrosis with marked calcification, similar to tuberculous lymphadenitis. Histopathologically, the lesion consisted of multiple coagulative necrotic foci and fibrosis with macrophage, lymphocyte, eosinophil and multinucleated giant cell infiltration. Non-uniform width hyphae were detected in the necrotic area and within the cytoplasm of the multinucleated giant cells, and they were found to be anti-Rhizopus arrhizus antibody positive in an immunohistochemical examination. Therefore, the steer was diagnosed with necrotic caudal mediastinal lymphadenitis due to zygomycetes infection, and inhibition of eructation by the enlarged lymph node was the likely cause of the ruminal tympany.

Detection of Visna Maedi virus in mesenteric lymph nodes and in other lymphoid tissues of sheep three years after respiratory infection

Visna/Maedi virus (VMV), a small ruminant lentivirus responsible for lymphoproliferative pneumonia, encephalitis, arthritis and/or mastitis in sheep, has been detected in different non-lymphoid organs. However, only a few investigations have been carried out in lymphoid tissues. In this study, some lymphoid tissues and lymph node draining or non-draining VMV target organs from five sheep infected experimentally by the respiratory route three years previously were investigated. Archival samples of spleen, red bone marrow, caudal mediastinal lymph nodes, mammary lymph nodes, popliteal lymph nodes and mesenteric lymph nodes were tested by PCR for the presence of proviral DNA. Popliteal and mesenteric lymph node samples were tested also by immunohistochemical staining of the viral capsid antigen p28. The proviral DNA was detected by PCR in all the lymphoid tissue samples from the infected sheep. The viral antigen was stained in mononuclear cells in popliteal and mesenteric lymph nodes of the infected sheep. Although the lymph nodes draining the classical target organs seem to be more infected than the others, both the viral capsid antigen and the proviral DNA were present also in lymph nodes draining non-target organs, such as the mesenteric lymph nodes. These findings show the presence of VMV in different lymphoid tissues in the late stages of infection and suggest a potential role of these tissues as a site for viral reservoir and replication, even three years after infection.  

Altered lymphatics in an ovine model of congenital heart disease with increased pulmonary blood flow

Abnormalities of the lymphatic circulation are well recognized in patients with congenital heart defects. However, it is not known how the associated abnormal blood flow patterns, such as increased pulmonary blood flow (PBF), might affect pulmonary lymphatic function and structure. Using well-established ovine models of acute and chronic increases in PBF, we cannulated the efferent lymphatic duct of the caudal mediastinal node and collected and analyzed lymph effluent from the lungs of lambs with acutely increased PBF (n = 6), chronically increased PBF (n = 6), and age-matched normal lambs (n = 8). When normalized to PBF, we found that lymph flow was unchanged following acute increases in PBF but decreased following chronic increases in PBF. The lymph:plasma protein ratio decreased with both acute and chronic increases in PBF. Lymph bioavailable nitric oxide increased following acute increases in PBF but decreased following chronic increases in PBF. In addition, we found perturbations in the transit kinetics of contrast material through the pleural lymphatics of lambs with chronic increases in PBF. Finally, there were structural changes in the pulmonary lymphatic system in lambs with chronic increases in PBF: lymphatics from these lambs were larger and more dilated, and there were alterations in the expression of vascular endothelial growth factor-C, lymphatic vessel endothelial hyaluronan receptor-1, and Angiopoietin-2, proteins known to be important for lymphatic growth, development, and remodeling. Taken together these data suggest that chronic increases in PBF lead to both functional and structural aberrations of lung lymphatics. These findings have important therapeutic implications that warrant further study.

Assessment of IgE response and cytokine gene expression in pulmonary efferent lymph collected after ovalbumin inhalation during experimental infection of calves with bovine respiratory syncytial virus

To assess IgE response and cytokine gene expressions in pulmonary lymph collected from bovine respiratory syncytial virus (BRSV)-infected calves after ovalbumin inhalation. Thirteen 7- to 8-week-old calves. The efferent lymphatic duct of the caudal mediastinal lymph node of each calf was cannulated 3 or 4 days before experiment commencement. Calves were inoculated (day 0) with BRSV (n = 7) or BRSV-free tissue culture medium (mock exposure; 6) via aerosolization and exposed to aerosolized ovalbumin on days 1 through 6 and day 15. An efferent lymph sample was collected daily from each calf on days -1 through 16; CD4+ and CD8+ T lymphocyte subsets in lymph samples were enumerated with a fluorescence-activated cell scanner. Expressions of several cytokines by efferent lymphocytes and lymph ovalbumin-specific IgE concentration were measured. Each calf was euthanized on day 16 and then necropsied for evaluation of lungs. Mean fold increase in ovalbumin-specific IgE concentration was greater in BRSV-infected calves than in mock-infected calves. At various time points from days 4 through 10, percentages of T lymphocyte subsets and CD4+:CD8+ T lymphocyte ratios differed between BRSV-infected calves and day -1 values or from values in mock-infected calves. On days 3 through 5, IL-4 and IL-13 gene expressions in BRSV-infected calves were increased, compared with expressions in mock-infected calves. Lung lesions were consistent with antigen exposure. In response to the inhalation of aerosolized ovalbumin, BRSV infection in calves appeared to facilitate induction of a T helper 2 cell response and ovalbumin-specific IgE production.

Computed tomography measurements of thoracic structures in 26 clinically normal goats

The present study was performed to provide computed tomographic (CT) reference values for structures in the thorax of 26 clinically normal Saanen goats. Animals were anesthetized, positioned in sternal recumbency and transverse images with a reconstructed 1.5 mm slice thickness were obtained by use of a 40-slice CT scanner. Absolute and relative measurements of the trachea, heart, cranial vena cava, thoracic aorta, caudal vena cava, right and left principal bronchus, right and left caudal lobar bronchus and the concomitant branch of the right and left pulmonary artery and vein, large caudal mediastinal lymph node and lung density were performed with dedicated software. Minimal to moderate interstitial or bronchopneumonia was incidentally found on CT in 24 animals. In conclusion, CT images obtained in this study can be used as a reference for the evaluation of thoracic diseases in goats.

Coinfection of a Cow with Bovine Leukemia Virus and Mycobacterium Bovis

Bovine leukosis associated with infection with the delta retrovirus Bovine leukemia virus (BLV) is endemic in many cattle herds in the United States. Infection has been associated with immunosuppression and decreased productivity. Cases of tuberculosis in cows due to infection with Mycobacterium bovis reemerged in Michigan in 1998, and despite intensive eradication attempts, new cases of bovine tuberculosis are sporadically identified. The present report details a coinfection with BLV and M. bovis in a Holstein cow from Michigan that presented as part of a bovine tuberculosis screening program. Peripheral and visceral lymph nodes of this animal were markedly enlarged, homogeneously pale white, and bulged on the cut surface. The submandibular, mesenteric, and caudal mediastinal lymph nodes contained multifocal to coalescing caseogranulomas that ranged from 1 to 5 cm in diameter. Histologically, dense sheets of monomorphic populations of neoplastic lymphocytes obliterated the normal architecture of all lymph nodes. Caseogranulomas were characterized by central pools of amorphous degenerate eosinophilic and occasionally mineralized granular debris surrounded by thick rims of epithelioid macrophages, occasional Langhan's type giant cells, and fibrosis. Polymerase chain reaction assay was positive for BLV. Cultures of affected lymph nodes yielded growth of M. bovis.

High Prevalence and Increased Severity of Pathology of Bovine Tuberculosis in Holsteins Compared to Zebu Breeds under Field Cattle Husbandry in Central Ethiopia

A comparative study on the prevalence and pathology of bovine tuberculosis (TB) was conducted on 5,424 cattle (2,578 zebus, 1,921 crosses, and 925 Holsteins), which were kept on pasture in the central highlands of Ethiopia, using a comparative intradermal tuberculin test, postmortem examination, and bacteriology. The overall prevalence of bovine TB was 13.5%; prevalence was higher in Holsteins than either zebus (22.2% versus 11.6%, chi(2) = 61.8; P < 0.001) or crosses (22.2% versus 11.9%, chi(2) = 50.7; P < 0.001). Moreover, the severity of pathology in Holsteins (mean +/- standard error of the mean [SEM], 6.84 +/- 0.79) was significantly higher (P = 0.018) than the severity of pathology in zebus (5.21 +/- 0.30). In addition, the risk of TB in Holsteins was more than twice (odds ratio [OR] = 2.32; 95% confidence interval [CI] = 1.89, 2.85) that in zebus. Animals between 5 and 9 years of age were at higher (OR = 2.37; 95% CI = 1.80, 3.12) risk of bovine TB than those 2 years of age or below. A significant difference (chi(2) = 351; P < 0.001) in the occurrence of TB lesions in lymph nodes was recorded; the mesenteric lymph node (mean pathology score +/- SEM, 1.95 +/- 0.08) was most severely affected, followed by the retropharyngeal (0.80 +/- 0.05) and caudal mediastinal (0.8 +/- 0.06) lymph nodes. Fifty-six percent (n = 145) of the animals with gross TB lesions were culture positive; the lowest culture positivity was recorded in the skin lesions (27.3%) and the lesions of the mesenteric lymph node (31.5%). Both the skin test response and the postmortem findings suggested a higher susceptibility to bovine TB in Holsteins than zebus under identical field husbandry conditions (on pasture). In the light of increased numbers of Holstein cattle introduced into this area to raise milk production to satisfy the needs of Addis Ababa's growing population, these findings highlight the need for a control program in these herds.

Eradication of ovine pulmonary adenocarcinoma by motherless rearing of lambs

The principles of maedi-visna eradication programmes were applied to a field trial for the eradication of ovine pulmonary adenocarcinoma (opa). In two maternal flocks the prevalence of gross and histological...

New method for evaluation of lung lymph flow rate with intact lymphatics in anaesthetized sheep

Lung lymph has commonly been studied using a lymph fistula created by tube cannulation into the efferent duct of the caudal mediastinal node in sheep. In this method, the tail region of the caudal mediastinal node is resected and the diaphragm is cauterized to exclude systemic lymph contamination, and cannulation is performed into one of the multiple efferent ducts originating from the caudal mediastinal node. Moreover, the pumping activity of lymphatics might be diminished by cannulation. Therefore, the purpose of the study was to evaluate the flow rate of lung lymph with maintenance of intact lymphatic networks around the caudal mediastinal node to the thoracic duct in sheep. An ultrasound transit-time flow meter was used to measure lung lymph flow. The thoracic duct was clamped just above the diaphragm and the flow probe was attached to the thoracic duct just after the last junction with an efferent duct from the caudal mediastinal node. The lung lymph flow rate was measured at baseline and under conditions of lung-oedema formation. The baseline lung lymph flow rate in our model was three- to sixfold greater than values obtained with the cannulation method. With oedema-formation, the lung lymph flow rate was the same as that measured using cannulation. The lung lymph flow was unexpectedly large under the conditions of the study, and our data suggest that the drainage effect of lymphatics is significant as a safety factor against pulmonary oedema formation.

Anatomy and nomenclature of murine lymph nodes: Descriptive study and nomenclatory standardization in BALB/cAnNCrl mice

Murine lymph nodes are intensively studied but often assigned incorrectly in scientific papers. In BALB/cAnNCrl mice, we characterized a total of 22 different lymph nodes. Peripheral nodes were situated in the head and neck region (mandibular, accessory mandibular, superficial parotid, cranial deep cervical nodes), and at the forelimb (proper axillary, accessory axillary nodes) and hindlimb (subiliac, sciatic, popliteal nodes). Intrathoracic lymph nodes included the cranial mediastinal, tracheobronchal and caudal mediastinal nodes. Abdominal lymph nodes were associated with the gastrointestinal tract (gastric, pancreaticoduodenal, jejunal, colic, caudal mesenteric nodes) or were located along the major intra-abdominal blood vessels (renal, lumbar aortic, lateral iliac, medial iliac and external iliac nodes). Comparative and nomenclative aspects of murine lymph nodes are discussed. The position of the lymph nodes of BALB/cAnNCrl mice is summarized and illustrated in an anatomical chart containing proposals for both an official nomenclature according to the Nomina Anatomica Veterinaria and English terms.

EFFECTS OF MANGANESE SUPEROXIDE DISMUTASE NEBULIZATION ON PULMONARY FUNCTION IN AN OVINE MODEL OF ACUTE LUNG INJURY

Smoke inhalation injury is a major cause of morbidity and mortality in thermally injured individuals. There is evidence of increased oxygen free radical activity, e.g., superoxide, in association with smoke inhalation injury. Because superoxide dismutase converts the reactive superoxide radical to peroxide, we hypothesized that nebulization of manganese superoxide dismutase (Mn-SOD) into the airway might attenuate pulmonary dysfunction secondary to smoke inhalation injury. The present study was designed as a prospective, controlled, and randomized laboratory experiment to determine the effects of aerosolized Mn-SOD on lung fluid balance, as indexed by changes in pulmonary microvascular permeability, lung lymph flow (Q(L)), and gas exchange in an established and clinically relevant ovine model of smoke inhalation injury. Fifteen female Merino sheep were chronically instrumented with a femoral arterial, a Swan-Ganz, and a left atrial catheter. In addition, the right caudal mediastinal lymph node was cannulated to measure Q(L) (mL.h(-1)). Pneumatic occluders were placed around the right pulmonary veins for the determination of the reflection coefficient (sigma). After 7 days of recovery, sheep were randomly allocated to (a) an untreated control group (4 groups of 12 breaths of cotton smoke), (b) an injured group treated with nebulized Mn-SOD (5 mg/kg), and (c) an injured group that received only the vehicle (nebulized saline). Nebulization was performed 1 h and 12 h after smoke inhalation. Mn-SOD nebulization attenuated the increase in both filtration coefficient and sigma and significantly decreased lung tissue conjugated dienes. However, there were no differences in Q(L), PaO2/FiO2 ratio, and bloodless lung wet/dry weight ratio between groups. Although Mn-SOD nebulization attenuated the loss of protein, it failed to improve lung edema and pulmonary gas exchange, thereby limiting its clinical use.

Cytotoxic T lymphocyte activity and cytokine expression in calves vaccinated with formalin-inactivated bovine respiratory syncytial virus prior to challenge

The development of effective, safe vaccines for human and bovine respiratory syncytial virus (RSV) has been problematic. Inactivated RSV vaccines are of variable efficacy; poor efficacy may be related to induction of ineffective cell-mediated immunity (CMI). To characterize CMI in calves vaccinated with formalin inactivated (FI) BRSV, 11 calves were vaccinated twice with FI-BRSV ( n=5) or mock vaccine ( n=6) at a 2 week interval and challenged 1 month later. Prior to challenge a cannula was placed in the efferent lymphatic of the caudal mediastinal lymph node of each calf; lymph derived lymphocytes (LDL) were collected for analysis of CMI. Cytotoxic T lymphocyte (CTL) activity by LDL and/or peripheral blood mononuclear cells (PBMC) was measured by 51Cr release on days 5, 7, 9, and 10 post-challenge. Messenger RNA for interferon gamma (IFN-γ), interleukin 2 (IL-2) and IL-4 was measured on days 0–10 by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) of RNA of LDL. BRSV-specific IFN-γ production by PBMC was measured on days 0 and 10 by ELISA. Clinical signs and postmortem changes following challenge were evaluated. There was no difference between groups in clinical signs, postmortem changes, CTL activity, cytokine message expression, or IFN-γ production. For both groups, percentage lysis by CTL peaked on days 7–10 and ranged from 11 to 25%. Failure of vaccination to prevent disease following challenge was likely associated with failure to prime for improved CMI responses.

Hepatic cryoablation-induced acute lung injury: pulmonary hemodynamic and permeability effects in a sheep model.

Hepatic cryoablation of 30% to 35% or more of liver parenchyma in a sheep model results in eicosanoid and nuclear factor-kappaB (NF-kappaB)-mediated changes in pulmonary hemodynamics and lung permeability. Laboratory. At initial thoracotomy, catheters were placed in the main pulmonary artery, left atrium, right carotid artery, and efferent duct of the caudal mediastinal lymph node for subsequent monitoring in adult sheep. After a 1- to 2-week period of recovery, animals underwent laparotomy and left-lobe cryoablation (approximately 35% by volume) with subsequent awake monitoring and on postoperative days 1 to 3. Cryoablation-induced lung permeability and hemodynamic changes were compared with baseline values in sheep that underwent instrumentation. Similarly handled sheep underwent resection of a similar volume of hepatic parenchyma or had pulmonary artery pressure increases induced by mechanical left atrial obstruction. Activation of NF-kappaB was assessed with electrophoretic mobility shift assay, and serum thromboxane levels were measured with mass spectroscopy. Cryoablation resulted in acutely increased mean pulmonary (20 to 35 cm water) and systemic pressures, which returned to baseline at 24 hours with no change in cardiac output. Serum thromboxane levels increased 30 minutes after cryoablation (9-fold) and returned to baseline at 24 hours. Activation of NF-kappaB was present in liver and lung tissue by 30 minutes after cryoablation. Lung lymph-plasma protein clearance markedly exceeded the expected increase from pulmonary pressures alone, and increased lymph-plasma protein ratio persisted after pulmonary artery pressures normalized. Similar changes were not associated with 35% hepatic resection. This study demonstrates that 35% hepatic cryoablation results in an acute but transient increase in pulmonary artery pressure that may be mediated by increased thromboxane levels. Increases in pulmonary capillary permeability are not accounted for by pressure changes alone, and may be a result of NF-kappaB-mediated inflammatory mechanisms. These data show that cryosurgery causes pathophysiological changes similar to those observed with endotoxin and other systemic inflammatory stimuli.

Comparison of different methods for diagnosis of bovine tuberculosis from tuberculin- or interferon-gamma-reacting cattle in Spain.

Of 1479 cattle from herds in Northwestern Spain previously diagnosed as tuberculosis (TB) positive, 218 animals which gave a positive tuberculin or interferon-gamma reaction were examined at the slaughterhouse. Medial retropharyngeal and caudal mediastinal lymph nodes, and any tissues containing lesions suspected to be tuberculous, were removed and submitted to the laboratory. Three techniques for diagnosis of TB were used: post mortem examination (PME), smear staining by means of auramine O method (AOM), and culture isolation in Coletsos and Lowenstein-Jensen media followed by confirmation of M. tuberculosis complex organisms using PCR (CIM-PCR). Only 123 (29.9%) of the 412 samples collected showed typical tuberculous lesions. Confirmed M. tuberculosis complex organisms were isolated in 144 cases, 114 of which were from tissues showing lesions (success rate of 92.8%). Smears were found positive in 113 cases, 96 of which came from lesions suspected to be tuberculous (success rate of 78.0%). The sensitivities of CIM-PCR compared with those of PME and AOM were 92.7% and 85.7%, respectively. Statistical analysis revealed that PME and AOM are good indicators of the presence of M. tuberculosis complex organisms in tuberculin- or interferon-gamma reacting cattle.

Bronchial vascular contribution to lung lymph flow

The lymphatic vessels of the lung provide an important route for clearance of interstitial edema fluid filtered from pulmonary blood vessels. However, the importance of lung lymphatics for the removal of airway liquid filtered from the systemic circulation of the lung has not been demonstrated. We studied the contribution of the bronchial vasculature to lung lymph flow in anesthetized, ventilated sheep (n = 35). With the bronchial artery cannulated and perfused (control flow = 0.6 ml. min-1. kg-1), lymph flow from the efferent duct of the caudal mediastinal lymph node was measured 1) during increased bronchial vascular perfusion (300% of control flow); 2) with a hydrated interstitium induced by a 1-h period of left atrial hypertension and subsequent recovery, both with and without bronchial perfusion; and 3) during infusion (directly into the bronchial artery) of bradykinin, an inflammatory mediator known to cause changes in bronchial vascular permeability. Increased bronchial perfusion for 90 min resulted in an average 35% increase in lung lymph flow. During left atrial hypertension, the increase in lung lymph flow was significantly greater with bronchial perfusion (339% increase over baseline) than without bronchial perfusion (138% increase). Furthermore, recovery after left atrial hypertension was more complete after 90 min without bronchial perfusion (91%) than with bronchial perfusion (63%). Infusion of bradykinin into the bronchial artery resulted in a prompt and prolonged 107% increase in lung lymph flow. This was not seen if the same dose was infused into the pulmonary artery. Thus bronchial vascular transudate contributes significantly to lymph flow from the efferent duct of the caudal mediastinal lymph node. These results demonstrate that lymph vessels clear excess fluid from the airway wall and should be considered when evaluating the effect of vascular leak in airway obstruction.