Vasileios K. Kouritas

Effect of histamine on the electrophysiology of the human parietal pleura

INTRODUCTION Histamine is involved in the pathogenesis of numerous diseases and regulates the permeability of different tissues. The aim of this study is to investigate the effects of histamine on the electrophysiology of human parietal pleura and the underlying mechanisms involved. MATERIALS AND METHODS Pleural specimens were obtained from patients subjected to thoracic surgery and were mounted in Ussing chambers. Histamine solutions (1μM to 1mM) were applied in native and pretreated specimens with dimetindene maleate, cetirizine, ranitidine, amiloride and ouabain. Trans-mesothelial resistance was determined (R(TM)). RESULTS Histamine induced a rapid R(TM) increase on the mesothelial (p = 0.008) and a decrease on the interstitial surface (p = 0.029). This effect was dose-dependent and was totally abolished by dimetindene maleate, cetirizine and amiloride and partially by ranitidine and ouabain. CONCLUSIONS Histamine induces acute electrochemical changes in human pleura mainly via interaction with the H(1) and partially with the H(2) histamine receptors. It also interferes with trans-cellular permeability and therefore may participate in pleural fluid recycling.

Isolated sternal fractures treated on an outpatient basis

AIM The aim of this study is to investigate the need for admission of patients with isolated sternal fracture (ISF) by prospectively and randomly discharging or admitting them. METHODS Patients with ISF after the completion of investigations were randomly discharged or admitted. Investigations performed included lateral chest x-ray; chest computed tomography; electrocardiogram; cardiac ultrasound; definition of C-reactive protein; and cardiac enzymes, such as creatine phosphokinase, myocardial branch of creatine phosphokinase, and troponin I (cardiac specific). These investigations were repeated after 6 hours in the admission and the next day in both groups. RESULTS Forty-two patients were included in the study. Twenty-one were admitted, whereas 21 were discharged. Electrocardiogram and ultrasound were normal in both groups upon presentation and the next day. Creatine phosphokinase and myocardial branch of creatine phosphokinase, although elevated at presentation, were normal the next day and similar in both groups. There was no morbidity, need for surgery, or mortality in both groups during a 6-month follow-up. CONCLUSIONS Patients with ISF can be discharged safely as soon as investigations are completed. Extensive myocardial assessment is not needed on the posttraumatic period. Myocardial involvement seems unlikely in patients with ISF, who can be treated with oral analgesics.

Nonsteroidal Anti-Inflammatory Drugs Alter the Human Mesothelial Pleural Permeability via Ion Cellular Transportation by Inhibiting Prostaglandin Synthesis

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are used in clinical practice as analgesics or anti-inflammatory drugs. Studies have implicated them in participating in permeability throughout various tissues such as the kidneys and lungs. Objective: The effect of NSAIDs on the pleural permeability and the underlying mechanisms whereby this effect is mediated were investigated. Methods: Parietal pleural specimens were obtained from patients subjected to thoracic surgery and were mounted in Ussing chambers. Solutions containing paracetamol, acetylsalicylic acid, diclofenac, lornoxicam, parecoxib and ibuprofen were added in the chambers facing the pleural and the outer-pleural surface. Prostaglandin E2 was similarly used to investigate prostaglandin synthesis involvement at low and high doses. Amiloride- and ouabain-pretreated specimens were used in order to investigate ion transportation involvement. Transmesothelial resistance (RTM) was determined as a permeability indicator. Results: Paracetamol, acetylsalicylic acid, diclofenac, lornoxicam and ibuprofen increased RTM on the pleural and outer-pleural surface, inhibited by amiloride and ouabain. Parecoxib had no effect on the RTM. Prostaglandin decreased RTM on the pleural and outer-pleural surface inhibited by amiloride, ouabain and ibuprofen. Conclusion: NSAIDs, except parecoxib, induce a rapid decrease of the pleural permeability by inhibiting cellular transportation, an effect that is mediated by prostaglandin synthesis inhibition.

Pleural electrophysiology variations according to location in pleural cavity

The aim of the study was to compare the electrophysiology profile of sheep pleura originated from different locations of the pleural cavity with the respective profile in humans. Sheep specimens obtained from upper and lower lung lobes, 1st-4th and 8th-12th rib, ventral-dorsal diaphragm and mediastinum were mounted between Ussing chambers. Human visceral tissues were obtained from patients subjected to lobectomy. Trans-mesothelial resistance (R(TM)) was determined as an indicator of the tissue permeability, while amiloride and ouabain were used as inhibitors of cellular transportation via ion transporters. Control values R(TM) were low in lower lobe visceral, caudal costal parietal and diaphragmatic pleura. Amiloride increased R(TM) at all locations except upper visceral and mediastinum. Higher R(TM) increases were found in caudal parietal and dorsal diaphragmatic samples. Ouabain increased R(TM) of lower visceral, caudal parietal and diaphragmatic pleura but not of mediastinal specimens. Observations made in sheep tissue were comparable with human visceral, parietal and mediastinal regions. In conclusion, results suggest heterogeneity of trans-mesothelial permeability among different pleural locations in sheep as was the case for humans. Thoracic surgeons should consider physiology function of each part of pleural cavity before pleural tissue manipulation. Observations made in sheep may be used to understand human physiology.

Paracetamol and ibuprofen block hydrothorax absorption in mice

OBJECTIVES Non-steroidal anti-inflammatory agents (NSAIDs) and paracetamol alter pleural permeability, hindering pleural fluid recycling. The aim of this study was to investigate the effect of different analgesic and anti-inflammatory agents on fluid recycling in an induced hydrothorax model in mice. METHODS Hydrothorax was induced in C57BL/6 mice by injecting 500 μl phosphate-buffered saline-bovine serum albumin 1% isosmotic in the right hemithorax. Paracetamol (1 g/kg), ibuprofen (250 mg/kg) and parecoxib (2 mg/kg) were administered systematically by intraperitoneal injections. Each drug group included eight mice, which were sacrificed at 2 h and 4 h, respectively, after injections. The remaining hydrothorax volume and total cells contained were determined. RESULTS Regarding the paracetamol and ibuprofen groups, the remaining hydrothorax volume was greater than in the control group (350 ± 61, 348 ± 62 and 270 ± 51 μl, respectively, P = 0.042) when mice were sacrificed within 2 h. Similar observations were made in groups sacrificed after 4 h (202 ± 45 and 198 ± 44 vs 107 ± 56 μl, respectively, P = 0.002). In the parecoxib group, the remaining hydrothorax volume was 122 ± 53 μl (P = 0.038 versus paracetamol and ibuprofen, P > 0.05 versus control group). At the same time, the absorption rate in the paracetamol and ibuprofen groups was lower than in the parecoxib and control groups (P = 0.033). In the parecoxib group, the absorption rate was lower than that in the control group after 2 h (P = 0.042). In the paracetamol and ibuprofen groups, the total cell count and the macrophage and the neutrophils counts were increased, compared with the control and parecoxib groups (P = 0.025, 0.028 and 0.032, respectively). CONCLUSIONS Paracetamol and ibuprofen acutely hinder pleural fluid recycling by lowering the fluid absorption rate (higher remaining hydrothorax volume), while they increased total white cell counts. COX-2s presented lower remaining hydrothorax volume without acutely increasing the absorption rate. These findings could present some relevance to the administration of painkillers in patients with pleural effusion after thoracotomy.

Variation of the postoperative fluid drainage according to the type of lobectomy

OBJECTIVES The pleural membrane of the lower pleural cavity has a greater ability to recycle fluid than the pleural membrane of the upper pleural cavity. During lobectomy, the visceral pleura is removed with the lobe, whereas the parietal pleura is traumatized during manipulation. This study investigates variations of the drainage according to the type of lobectomy and its relation to effusion-related complications. METHODS Data of upper and lower lobectomy patients were compared with those of wedge resection patients. All patients were suctioned until totally dry before closure, and one chest tube was left in the hemithorax. The amount of fluid drained per day, the duration of drainage, the length of hospital stay and the morbidity were noted. Students paired t-test and Mann-Whitney U-test were used for comparison; P < 0.05 was defined as statistically significant. RESULTS Patients after lower lobectomy had more fluid drained when compared with patients after upper lobectomy or wedge resection on the first (636 ± 90, 268 ± 75 and 225 ± 62 ml, respectively; P = 0.002) and second postoperative day (464 ± 94, 237 ± 90 and 220 ± 62 ml, respectively; P = 0.046). The drainage tube was removed earlier in patients with upper lobectomy procedures than in patients with lower lobectomy procedures (4.6 ± 0.9 vs 8.1 ± 1.4 days; P = 0.014). Effusion-related complications developed in lower lobectomies with a higher output from the second postoperative day. CONCLUSIONS A larger amount of fluid is drained after removal of the lower lobes, possibly because the important fluid-recycling ability of the lower parts of the cavity is malfunctioning. Early drainage tube removal after lower lobectomy may be reconsidered when taking into account the possibility of effusion-related complications.

Staphylococcal isolated anterosuperior mediastinal abscess of unknown origin.

Mediastinal abscess is a rare presentation of infections involving the mediastinum. In rare cases, the origin of the infection cannot be identified. We report a case of a 32-year old male who was presented with a mediastinal abscess with an otherwise clear history. The origin of the infection could not be identified despite extensive investigations. The patient was operated through a cervical incision. His postoperative recovery was uneventful. Rare causes of mediastinal infections should not be overlooked from the diagnostic process even if the origin of infection cannot be identified.

Permeability Alterations after Surgical Trauma in Normal Rabbit Peritoneum

Background: To investigate whether surgical trauma in a rabbit adhesion formation model and the administration of normal saline (N/S), icodextrin (ID) and/or dimetindene maleate (DM) changes the permeability of the normal rabbit parietal peritoneum. Materials and Methods: A total of 45 female rabbits were operated on for adhesion formation and were euthanized 10 days later. In some rabbits, ID or N/S was instilled intraabdominally during operation, whereas in others DM was infused intravenously. In others, ID plus DM or no agent was used. Specimens were obtained postoperatively and were mounted between Ussing chambers. Amiloride was used to investigate Na+ channels. Transmesothelial resistance (RTM) was determined as a permeability indicator. Results: Amiloride increased the RTM of both surfaces. Surgical trauma increased RTM and partially inhibited the effect of amiloride. ID and N/S increased RTM and inhibited the effect of amiloride. Use of DM did not change RTM and did not inhibit the effect of amiloride. Use of ID plus DM slightly increased RTM, but the effect of amiloride was blocked. Conclusions: Surgical trauma impairs the permeability of the normal rabbit parietal peritoneum. ID or N/S surmounted this effect, but DM did not, suggesting that surgical trauma is a diffuse process. Antiadhesion measures influence peritoneal physiology.

Rib fractures with heamothorax after labor: a case report

IntroductionMaternal thoracic trauma during labor is extremely rare.Case presentationA woman was presented at the Accident and Emergency Department complaining of pain over the lower thorax bilaterally which started after a difficult delivery when the obstetrician forced her lower thorax. Small right-sided haemothorax and rib fractures bilaterally were diagnosed and she was admitted to hospital. Her in-hospital stay and follow up was uneventful.ConclusionManeuvers during labor should be applied from trained personnel and should be performed safely.

IGF-1 alters the human parietal pleural electrochemical profile by inhibiting ion trans-cellular transportation after interaction with its receptor

OBJECTIVE The effect of IGF-1 in the human pleural permeability and the underlying mechanisms involved were investigated. DESIGN Specimens from thoracic surgical patients were mounted in Ussing chambers. Solutions containing IGF-1 (1 nM-100 nM) and IGF-1 Receptor Inhibitor (1 μΜ), amiloride 10 μM (Na(+) channel blocker) and ouabain 1 mM (Na(+)-K(+) pump inhibitor) were used in order to investigate receptor and ion transporter involvement respectively. Trans-mesothelial Resistance (R(TM)) across the pleural membrane was determined as a permeability indicator. Immunohistochemistry for IGF-1 receptors was performed. RESULTS IGF-1 increased R(TM) when added on the interstitial surface for all concentrations (p=.008, 1 nM-100 nM) and decreased it on the mesothelial surface for higher concentrations (p=.046, 100 nM). Amiloride and ouabain inhibited this effect. The IGF-1 Receptor Inhibitor also totally inhibited this effect. Immonuhistochemistry demonstrated the presence of IGF-1 receptors in the pleura. CONCLUSIONS It is concluded that IGF-1 changes the electrophysiology of the human parietal pleura by hindering the normal ion transportation and therefore the pleural fluid recycling process. This event is achieved after IGF-1 interaction with its receptor which is present in the human pleura.