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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surgical stress and general anesthesia can suppress immune function and thus may increase postsurgical infections and tumor metastasis. We previously reported that two narcotics commonly used in high-dose opiate anesthesia (fentanyl and sufentanil) suppress natural killer (NK) cell activity in rats. Such doses of narcotics also cause respiratory depression accompanied by hypoxia, hypercarbia, and acidosis, which might account for the observed narcotic-induced NK suppression. In the present study, we compared the effects of fentanyl on NK activity in ventilated and non-ventilated rats. Fentanyl significantly suppressed NK cell activity to the same magnitude in the two groups, although the groups significantly differed in CO2 and O2 levels. The fact that high-dose fentanyl-induced NK suppression can be demonstrated in ventilated rats accentuates the relevance of these findings to clinical studies showing NK suppression in the immediate postoperative period. Such immunosuppression could be a risk factor for patients undergoing surgery, especially in cancer-related operations.
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PMID:Narcotic-induced suppression of natural killer cell activity in ventilated and nonventilated rats. 164 47

We present herein clinical experience of neurosurgical anesthesia and cerebral protection in 66 cases, including 27 with supratentorial mass, 28 posterior fossa tumor and 11 cerebral vascular deformity. Our methods for the control of intracranial pressure (ICP) and cerebral blood flow (CBF) during neurosurgical anesthesia were as follows: (1) avoidance of the drugs adversely influenced on ICP; (2) use of lidocaine iv. infusion; (3) prevention of hypercapnia; (4) maintenance of adequate perfusion of vital organs; (5) drainage of cerebrospinal fluid if necessary; (6) use of free radical clearing agents. We conclude that they are key points of effective control of ICP and maintenance of CBF so as to prevent cerebral ischemic effect on neurological function.
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PMID:[Cerebral protection in neurosurgical anesthesia]. 187 98

Most vasoactive drugs do not readily penetrate the blood-brain barrier and do not affect cerebral blood flow. We tested the hypothesis that vasoactive drugs may alter blood flow to brain tumors in which the blood-brain barrier is abnormal. Blood flow was measured with microspheres in dogs with brain tumors induced by avian sarcoma virus. Intravenously administered adenosine increased blood flow to tumor more than twofold but did not alter flow to normal brain. Intravenously administered norepinephrine decreased blood flow to tumor but not to normal brain. Thus, vasoactive drugs, which have little effect on blood flow to normal cerebrum, produce large changes in blood flow to brain tumors. We also examined responses to systemic hypercapnia. Hypercapnia increased blood flow to normal cerebrum more than twofold but failed to increase flow to tumors. Impaired vasodilator responses to hypercapnia in brain tumors, which cannot be explained primarily by an abnormality of the blood-brain barrier, probably reflect another fundamental difference between vessels in normal brain and brain tumors. The finding that vasoactive drugs have selective effects on blood flow to brain tumors has important implications for delivery of lipid-soluble chemotherapeutic drugs to the tumors.
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PMID:Vasoactive drugs produce selective changes in flow to experimental brain tumors. 300 39

The authors discuss the gross and microscopic anatomy and the physiology of the cerebral venous system. Cerebral veins under pathological circumstances (hypercapnia, arterial hypertension, and increased intracranial pressure), pharmacological observations, the venous blood-brain barrier, and traumatic involvement are reviewed. Neoplastic involvement and radiological aspects are included. Surgical reconstruction of venous sinuses (including the Donaghy technique), tumor removal, sinus thrombectomy, and extraanatomical bypass of the transverse sinus are discussed.
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PMID:The cerebral venous system. 390 42

Seven patients are described who had a distinctive syndrome of chest wall restriction caused by asbestos-induced pleural fibrosis. All had severe dyspnea and predominant pleural disease on radiographic examination, with pulmonary function findings of reduced vital capacity, total lung capacity (measured in five patients), and maximal voluntary ventilation. Five patients had ventilatory failure with carbon dioxide retention; four of these have died and one is close to death. Examination of the thoracic organs in five patients showed minimal or no parenchymal fibrosis in three and less severe involvement of the parenchyma than of the pleura in the remaining two. Neoplasms were suspected in three patients because of extension of the pleural fibrosis into the lung. Two of these patients had pleural uptake of 67-gallium citrate attributable to the inflammatory reaction. With the increasing duration since onset of exposure in the nine million workers who have been exposed to asbestos, as well as in other exposed persons, it is expected that additional cases of ventilatory failure caused by asbestos-induced pleural fibrosis will be encountered.
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PMID:Ventilatory failure due to asbestos pleurisy. 665 May 44

An experience of surgical non-thoracic emergencies in patients admitted for chronic lung disease is herein presented. Fifty-four patients out of 10457 admitted in the four Departments of Pneumology of the Binaghi Hospital (Cagliari) between 1-1-1985 and 31-3-1993, were referred to our Department of General Surgery due to non-thoracic surgical emergencies. There was a considerable delay in the referral (only 25% of patients within 12 hours from the onset of symptoms): indeed predominant respiratory symptoms, hypoxia and hypercapnia made these patients no responsive to symptoms of surgical emergency. Surgical emergencies in causal correlation with respiratory disease (intestinal occlusion due to abdominal metastases of lung carcinoma, complicated peptic ulcer) had the worst prognosis (mortality: 52.9%). Those in chance connection, such as acute limb ischemia and preexisting abdominal disease, had a less adverse outcome. Mortality, however, was 37.5%: this datum outlines the role of chronic lung disease in defining operative risk. The authors call attention to three groups of observed patients: 1) three patients were operated on for intestinal occlusion due to unrecognized abdominal neoplasia, that showed itself in the course of hospitalization in the Department of Pneumology for lung metastases; 2) in 3 cases symptoms and signs of acute abdomen were observed without abdominal disease. The cause of acute pseudoabdomen was diaphragmatic pleural or basal pulmonary inflammation; 3) the eight patients with pulmonary embolism were all admitted in the Department of Pneumology with a wrong diagnosis of bronchopneumonia.
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PMID:[Extrathoracic surgical emergencies in hospitalized patients with bronchopulmonary diseases. Analysis of the operative risk]. 780 66

The tumor interstitial pH and its modification play a significant role in cancer treatment. Current in vivo pH measurement techniques are invasive and/or provide poor spatial resolution. Therefore, there are no data on perivascular interstitial pH gradients in normal or tumor tissue. We have optically measured interstitial pH gradients with high resolution in normal and tumor (VX2 carcinoma) tissue in vivo by combining a fluorescence ratio imaging microscopy technique and the rabbit ear chamber preparation. The strengths of our approach include the ability to follow pH in the same location for several weeks and to relate these measurements to local blood flow and vascular architecture. Our results show: (a) tumor interstitial pH (6.75 units; N = 6 animals, n = 324 measurements) is significantly (P < 0.001) less than normal interstitial pH (7.23; N = 5, n = 274). This increased acidity in the tumor interstitium is in agreement with the previously reported data on this tumor; (b) with respect to pH spatial gradients in normal tissue, the interstitial pH decreased by approximately 0.32 pH units over a distance of 50 microns away from the blood vessel, while in tumor tissue, interstitial pH decreased by approximately 0.13 units over the same distance. Although the pH gradient near the vessel wall was steeper in normal tissue compared to tumor, the proton concentration gradient in normal tissue was less than that in the tumor. The approximate increase in proton concentration from 0-50 microns from the vessel was 4.5 x 10(-8)M in normal versus 5.7 x 10(-8)M in tumor tissue; (c) a simple one-dimensional diffusion-reaction model suggested that tumor tissue was producing protons at a rat 65-100% greater than normal tissue; (d) feasibility studies of temporal dynamics resulting from hyperglycemia (6 g/kg) or hypercapnia (10% CO2) led to significant (P < 0.05) interstitial pH reductions. During hyperglycemia, pH dropped by more than 0.2 pH units in about 90 min in tumor tissue but remained constant in normal tissue. Hypercapnia dramatically reduced pH by approximately 0.3 pH units in tumor tissue. Our limited studies on hyperglycemia and hypercapnia are in agreement with the previously published studies and demonstrate the capability of fluorescence ratio imaging microscopy to measure spatial as well as temporal changes in interstitial pH. Fluorescence ratio imaging microscopy should permit noninvasive evaluation of new pH-modifying agents and offer unique mechanistic information about tumor pathophysiology in tissue preparations where the surface of the tissue can be observed.
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PMID:Noninvasive measurement of interstitial pH profiles in normal and neoplastic tissue using fluorescence ratio imaging microscopy. 792 15

We report on two patients with subcutaneous carbon dioxide (CO2) emphysema that developed during laparoscopic surgery with CO2 pneumoperitoneum (PP), in whom pulmonary elimination of CO2 (ECO2, Servo ventilator with integrated CO2 analyzer 930, Siemens) was continuously monitored. Patient 1 was a 61-year-old man with laparoscopic herniotomy. ECO2 immediately before PP was 120 ml/min x m2 and increased rapidly after 45 min PP to a maximum value of 340 ml/min x m2. At that time, minute ventilation had been increased from 7 to 11 l/min and PaCO2 had risen from 35 to 57 mm Hg. At the end of the procedure the patient showed excessive subcutaneous emphysema. Patient 2 was a 71-year-old woman in whom diagnostic laparoscopy was performed for staging of a pancreatic tumor. ECO2 immediately before PP was 140 ml/min x m2, increasing dramatically after 45 min PP to a maximum value of 529 ml/min x m2 (Fig. 1). At that time minute ventilation had been increased from 6.2 to 12.5 l/min and PaCO2 had risen from 40 to 77 mm Hg. PP was terminated and the patient was found to have extreme subcutaneous emphysema. She was mechanically ventilated for a further 40 min to normalize PaCO2 and ECO2. It seems reasonable to suppose that an increase in ECO2 by more than 100% of control during CO2-PP is an early sign of CO2 emphysema. In this situation hypercapnia is potentially life-threatening. Evidently, reabsorption of CO2 from loose connective tissue is far more rapid and effective than CO2 resorption from the peritoneal cavity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[CO2--emphysema in laparoscopic surgery. Changes in pulmonary CO2-elimination]. 809 57

Endothelin-1 (ET-1) is produced by some tumor cells, but the dependence of this production on pO2 and pCO2, conditions relevant within the tumor microenvironment, has not been described. HT29 colon adenocarcinoma cells and DU145 prostate carcinoma cells produce similar amounts of ET-1 in vitro under normal cell culture conditions of 21% O2/5% CO2 (normoxia). Exposure of HT29 cells to either 2% O2 or 0.2% O2 significantly reduced ET-1 production compared to cells in normoxia. In contrast, production of ET-1 by DU145 cells was usually unaffected by hypoxia and was even slightly increased in cells exposed to 2% O2 in HEPES-buffered EMEM (HEPES-EMEM). Exposure of cells to either 2.2% CO2 or 7.1% CO2 had no effect on the production of ET-1 by cells in bicarbonate-buffered EMEM (EMEM). However, in HEPES-EMEM, ET-1 production by both cell lines was reduced in 7.1% CO2. A slight reduction in ET-1 produced by DU145 cells was also observed in 2.2% CO2. These results illustrate that changes in ET-1 production by tumor cells in response to hypoxia and hypercapnia are tumor-dependent. It is clear that the production of ET-1 by tumor cells under normal culture conditions may not accurately reflect production within the tumor microenvironment. A greater insight into the in vivo situation, however, may be possible by modifying the cell culture conditions.
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PMID:The effect of oxygen and carbon dioxide on tumor cell endothelin-1 production. 959 36

Insufflation with helium is used to prevent respiratory acidosis, hypercapnia, and cardiovascular instability associated with carbon dioxide (CO2) pneumoperitoneum. The aim of this prospective study was to compare CO2 with helium pneumoperitoneum with special reference to respiratory and hemodynamic changes at different times during the operation. Altogether 22 pheochromocytoma patients undergoing laparoscopic adrenalectomy (LpA) were included using CO2 in 11 patients (CO2LpA) and helium in 11 patients (HeLpA). The insufflation pressure was 12 mmHg. The two groups were comparable with regard to demographic data and preoperative management. CO2 and helium insufflation were associated with similar catecholamine increase. The most striking significant increase compared with the baseline was observed during tumor isolation: The mean plasma epinephrine (EPI) and norepinephrine (NE) levels increased 32.86-fold and 25.92-fold, respectively, in the CO2LpA patients and 27.43-fold and 18.46-fold, respectively, in the HeLpA patients. HeLpA did not result in significant hypercarbia or acidosis at any measured intraoperative point; this was without any alteration in minute ventilation to maintain these normal PaCO2, excess base (EB), and pH values. Significant increases of mean arterial pressure, pulmonary arterial pressure, pulmonary vascular resistance index, PaCO2, EB, and acidosis were seen in the CO2LpA patients at the time of tumor isolation and tumor removal compared with those in HeLpA patients. No patient required conversion to open surgery. There were no significant differences between CO2LpA and HeLpA regarding mean operative time (117.50 +/- 93.68 vs. 106.87 +/- 16.60 minutes), mean blood loss (168.54 +/- 78.63 vs. 142.02 +/- 109.26 ml), hospital stay (4 days), the need for analgesics, or mean time required to return to normal activity (12 days). There was one wound infection in the HeLpA group and one wound hematoma and one case of atelectasis in the CO2LpA group. Helium may be the agent of choice for abdominal insufflation in patients undergoing LpA for pheochromocytoma, eliminating the adverse hemodynamic and respiratory changes associated with CO2 insufflation.
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PMID:Helium and carbon dioxide pneumoperitoneum in patients with pheochromocytoma undergoing laparoscopic adrenalectomy. 984 53


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