Utility of intraoperative lung ultrasonography.

A patient with an endobronchial tumor and critical airway obstruction developed hypoxia and hypercarbia and, subsequently, cardiac arrest during a palliative laser core-out excision. The differential diagnosis included tension pneumothorax, as well as airway obstruction due to swelling of residual tumor or to blood clots. In this case, empiric needle decompression could have had deleterious consequences. Immediate bedside lung ultrasonography provided real-time information leading to the stabilization of the patient. This case provides compelling motivation for anesthesiologists to acquire this easily learned skill.

Modified labeling technique for in vivo visualization of platelets in the cerebral microcirculation of Mongolian gerbils.

Activation of platelets induces interactions with platelets, endothelial cells, and leukocytes. In vivo observation of these interactions in the cerebral microcirculation is rare. The purpose of the present study was to develop a model enabling the in vivo observation of platelet kinetics in the cerebral microcirculation. Intravital fluorescence microscopy was performed in the Mongolian gerbil. Platelets of a donor were labeled ex vivo with carboxyfluorescein diacetat-succinimidylester (CFDA-SE), providing long-term fluorescence. Platelet function was tested ex vivo by flow cytometric analysis and in vivo by analyzing platelet-endothelium interactions. Labeled platelets stimulated with adenosine diphosphate ADP (200 micromol/L) or thrombin (1000 U/L) showed aggregation in flow cytrometric analysis, whereas unstimulated platelets were not aggregated. Irradiation of the brain surface after intravenous injection of the photosensitizing dye Photosan first induced rolling and firm adherence of platelets on arteriolar and venular endothelium, followed by the formation of a thrombus obstructing the vessel. Quantitative analysis (n x 100 microm(-1) min(-1)) before and after 6 mins of irradiation showed 2.6+/-3.2 versus 29.0+/-28.9 rolling, and 0.0+/-0.0 versus 1.7+/-2.3 firm adherent platelets in arterioles, and 3.9+/-3.3 versus 36.6+/-20.9 rolling and 0.0+/-0.0 versus 13.6+/-8.9 firm adherent platelets in venules. Thus, we conclude that ex vivo labeling of platelets with CFDA-SE does not activate platelets. Platelet aggregation and adhesion was achieved by platelet-specific stimulation such as ADP, thrombin or irradiation. In vivo assessment of physiologic and pathophysiologic mechanisms of platelets in the cerebral microcirculation can be achieved in this model.

Giant pulmonary hamartoma--a rare presentation of a common tumor.

Hamartomata, the most common benign tumors of the lung, are rarely symptomatic and usually come to clinical attention as coin-shaped lesions on a routine plain chest roentgenogram. We report a case of a 63-year-old woman presenting with reduced endurance on exercise. The plain chest roentgenogram showed a tumor in the left chest. After clinical work-up, the patient underwent radical tumor resection through a lateral thoracotomy. The resected tumor, with two separate nodules, measured 26 x 25 cm and weighed 3.2 kg. The histopathology work-up showed pulmonary hamartoma.

Recombinant human hemoglobin with reduced nitric oxide-scavenging capacity restores effectively pancreatic microcirculatory disorders in hemorrhagic shock.

BACKGROUND: Scavenging of nitric oxide by hemoglobin-based oxygen carriers could aggravate microcirculatory failure in splanchnic organs after hemorrhagic shock as a consequence of vasoconstrictive side effects. The aim of this study was to compare the effects of two recombinant human hemoglobin solutions, a second-generation product bearing reduced nitric oxide-scavenging properties (rHb2.0) due to site directed mutagenesis of the heme pocket and a first-generation recombinant hemoglobin (rHb1.1) with scavenging capacity similar to native hemoglobin, on the pancreatic microcirculation after hemorrhagic shock. METHODS: Twenty-eight pentobarbital-anesthetized rats were bled to a mean arterial pressure of 40 mmHg and maintained at this level for 1 h. Using an intravital microscope, the length of erythrocyte-perfused pancreatic capillaries per observation area (functional capillary density) were measured in animals resuscitated by volumes of hydroxyethyl starch, rHb1.1, or rHb2.0 equivalent to the shed blood volume. Animals without shock induction served as control. RESULTS: As compared with control (438 +/- 10 cm(-1)), animals treated with hydroxyethyl starch (315 +/- 44 cm(-1)) and rHb1.1 (288 +/- 67 cm(-1)) showed a significant reduction of functional capillary density after 2 h of resuscitation. rHb2.0 was able to restore functional capillary density (410 +/- 42 cm(-1)) and mean arterial pressure to baseline values. CONCLUSION: rHb2.0 was effectively able to restore pancreatic microcirculation after hemorrhagic shock. This may be related to the compound's effective lack of nitric oxide-scavenging properties. This hemoglobin solution or ones similar to it might be uniquely valuable for resuscitation from hemorrhagic shock.

Visualization of leukocyte transendothelial and interstitial migration using reflected light oblique transillumination in intravital video microscopy.

Dynamic visualization of the intravascular events leading to the extravasation of leukocytes into tissues by intravital microscopy has significantly expanded our understanding of the underlying molecular processes. In contrast, the detailed observation of leukocyte transendothelial and interstitial migration in vivo has been hampered by the poor image contrast of cells within turbid media that is obtainable by conventional brightfield microscopy. Here we present a microscopic method, termed reflected light oblique transillumination microscopy, that makes use of the optical interference phenomena generated by oblique transillumination to visualize subtle gradients of refractive indices within tissues for enhanced image contrast. Using the mouse cremaster muscle, we demonstrate that this technique makes possible the reliable quantification of extravasated leukocytes as well as the characterization of morphological phenomena of leukocyte transendothelial and interstitial migration.

Platelet-endothelial interaction in tumor angiogenesis and microcirculation.

Activated platelets release angiogenic growth factors and have therefore been proposed to contribute to tumor angiogenesis within a potentially prothrombotic tumor microcirculation. The aim of the study was to investigate interactions of platelets with the angiogenic microvascular endothelium of highly vascularized solid tumors during growth and in response to endothelial stimulation in comparison with normal subcutaneous tissue. Experiments were performed in the dorsal skinfold chamber preparation of C57BL/6J mice bearing the Lewis lung carcinoma (LLC-1) or methylcholanthrene-induced fibrosarcoma (BFS-1). Fluorescently labeled rolling and adherent platelets, red blood cell velocity, and vessel diameters were assessed by intravital fluorescence microscopy on days 1, 3, 8, and 14 after tumor cell implantation. Slightly elevated numbers of rolling platelets were observed in the early stages of tumor angiogenesis at day 1 (control, 1.7 +/- 0.6; LLC-1, 3.4 +/- 1.8; BFS-1, 3.0 +/- 0.7 [1/mm/s], P <.05) and day 3 (control, 1.6 +/- 0.6; LLC-1, 4.1 +/- 1.7, P <.05; BFS-1, 2.3 +/- 0.5 [1/mm/s]) after tumor cell implantation. Endothelial stimulation with calcium ionophore A23187 at day 14 after tumor cell implantation resulted in a minor increase to 2.1 +/- 0.4 (LLC-1) and 1.8 +/- 0.8 (BFS-1) rolling platelets (1/mm/s) in tumor microvessels compared with 4.9 +/- 0.9 in controls (P <.05). Platelet adherence was not observed. We therefore conclude that in the 2 experimental tumors under study, (1) slightly increased platelet rolling is a transient phenomenon after tumor cell implantation, and (2) platelet-endothelial interaction in response to endothelial stimulation is reduced in tumor microvessels.

P-selectin mediates platelet-endothelial cell interactions and reperfusion injury in the mouse liver in vivo.

Platelets are suggested to participate in the pathogenesis of hepatic ischemia-reperfusion (I/R) injury. This study was designed to analyze platelet-endothelial cell interactions in the postischemic mouse liver in vivo and to define the role of endothelial versus platelet P-selectin for these interactions. Platelet-endothelial cell interactions were quantitatively analyzed using intravital fluorescence microscopy after lobar hepatic I/R in C57BL/6 wild-type and P-selectin-deficient mice after infusion of ex vivo rhodamine-6G-labeled wild-type and P-selectin-deficient platelets. Reperfusion injury and apoptosis were assessed by established methods. In wild-type animals, hepatic I/R caused significantly enhanced platelet-endothelial cell interactions in terminal arterioles and postsinusoidal venules as well as platelet stagnation in sinusoids. Concomitantly, transaminase and caspase-3 activities were elevated and sinusoidal perfusion was impaired. In contrast, platelet-endothelial cell interactions were nearly absent in arterioles and venules of mice lacking endothelial P-selectin, irrespective of the presence of P-selectin on infused platelets, but still significantly elevated in sinusoids. Simultaneously, sinusoidal perfusion failure was ameliorated, and transaminase- and caspase-3 activities were significantly reduced in P-selectin-deficient mice as compared with wild-type animals. The present intravital microscopic study provides, for the first time, quantitative analyses of platelet-endothelial cell interactions in the postischemic hepatic microcirculation. Our in vivo data show that endothelial P-selectin is critical for postischemic platelet-endothelial cell interactions within hepatic presinusoidal arterioles and postsinusoidal venules. P-selectin deficiency prevents microvascular injury and apoptosis after warm hepatic I/R.

Platelet adhesion mediated by fibrinogen-intercelllular adhesion molecule-1 binding induces tissue injury in the postischemic liver in vivo.

BACKGROUND: Platelets are thought to be involved in the induction of hepatic ischemia-reperfusion (I/R) injury. The mechanisms of platelet adhesion in the hepatic microvasculature and the role of platelets in the pathogenesis of I/R-induced liver damage in vivo remain unclear. METHODS: In C57BL/6 mice, platelet- and leukocyte-endothelial cell interactions were quantitatively analyzed using intravital fluorescence microscopy in sham-operated animals, after warm lobar hepatic I/R (90/20 min) in wild-type and intercellular adhesion molecule (ICAM)-1-deficient mice, and after I/R in wild-type mice treated with an antifibrinogen antibody. Fibrinogen deposition on the endothelium was detected by intravital microscopy and by immunostaining. Reperfusion injury was assessed by measurement of liver enzyme and caspase-3 activities and of lipid peroxidation. RESULTS: Hepatic I/R induced fibrinogen deposition on hepatic endothelium, followed by a dramatic increase in the number of firmly adherent platelets in the liver microvasculature. Simultaneously, the number of adherent leukocytes in postsinusoidal venules and the aspartate aminotransferase/alanine aminotransferase and caspase-3 activities were elevated. Although ICAM-1 deficiency attenuated postischemic adherence of both platelets and leukocytes, the application of an antifibrinogen antibody selectively reduced the number of adherent platelets but did not influence leukocyte adhesion. The selective blockade of platelet adherence significantly prevented the postischemic increase in liver enzyme and caspase-3 activities. Furthermore, sinusoidal perfusion failure and lipid peroxidation were attenuated in the treated group. CONCLUSIONS: These in vivo data show that platelet adhesion mediated through fibrinogen deposition on ICAM-1 expressed on the endothelium of postischemic hepatic microvessels induces microvascular injury and hepatocellular apoptosis after I/R of the liver during early reperfusion.