Exogenous surfactant and positive end-expiratory pressure in the treatment of endotoxin-induced lung injury

OBJECTIVE: To evaluate the efficacy of treating endotoxin-induced lung injury with single dose exogenous surfactant and positive end-expiratory pressure (PEEP). DESIGN: Prospective trial. SETTING: Laboratory at a university medical center. SUBJECTS: Nineteen certified healthy pigs, weighing 15 to 20 kg. INTERVENTIONS: Pigs were anesthetized and surgically prepared for hemodynamic and lung function measurements. Animals were randomized into four groups: a) Control pigs (n = 4) received an intravenous infusion of saline without Escherichia colilipopolysaccharide (LPS); b) the LPS group (n = 5) received an intravenous infusion of saline containing LPS (100 microg/kg); c) the PEEP plus saline group (n = 5) received an intravenous infusion of saline containing LPS. Two hours after LPS infusion, saline was instilled into the lung as a control for surfactant instillation, and the animals were placed on 7.5 cm H2O of PEEP; d) the PEEP plus surfactant group (n = 5) received an intravenous infusion of saline containing LPS. Two hours following LPS infusion, surfactant (50 mg/kg) was instilled into the lung and the animals were placed on 7.5 cm H2O of PEEP. PEEP was applied first and surfactant or saline was instilled into the lung while maintaining positive pressure ventilation. All groups were studied for 6 hrs after the start of LPS injection. At necropsy, bronchoalveolar lavage was performed and the right middle lung lobe was fixed for histologic analysis. MEASUREMENTS AND MAIN RESULTS: Compared with LPS without treatment, PEEP plus surfactant significantly increased PaO2 (PEEP plus surfactant = 156.6 +/- 18.6 [SEM] torr [20.8 +/- 2.5 kPa]; LPS = 79.2 +/- 21.9 torr [10.5 +/- 2.9 kPa]; p<.05), and decreased venous admixture (PEEP plus surfactant = 12.5 +/- 2.0%; LPS = 46.9 +/- 14.2%; p< .05) 5 hrs after LPS infusion. These changes were not significant 6 hrs after LPS infusion. PEEP plus surfactant did not alter ventilatory efficiency index (VEI = 3800/[peak airway pressure - PEEP] x respiratory rate x PacO2), or static compliance as compared with LPS without treatment at any time point. Cytologic analysis of bronchoalveolar lavage fluid showed that surfactant treatment significantly increased the percentage of alveolar neutrophils as compared with LPS without treatment (PEEP plus surfactant = 39.1 +/- 5.5%; LPS = 17.4 +/- 6.6%; p< .05). Histologic analysis showed that LPS caused edema accumulation around the airways and pulmonary vessels, and a significant increase in the number of sequestered leukocytes (LPS group = 3.4 +/- 0.2 cells/6400 micro2; control group = 1.3 +/- 0.1 cells/6400 micro2; p < .05). PEEP plus saline and PEEP plus surfactant significantly increased the total number of sequestered leukocytes in the pulmonary parenchyma (PEEP plus surfactant = 8.2 +/- 0.7 cells/6400 micro2; PEEP plus saline = 3.9 +/- 0.2 cells/6400 micro2; p <.05) compared with the control and LPS groups. CONCLUSIONS: We conclude that PEEP plus surfactant treatment of endotoxin-induced lung injury transiently improves oxygenation, but is unable to maintain this salutary effect indefinitely. Thus, repeat bolus dosing of surfactant or bolus treatment followed by continuous aerosol delivery may be necessary for a continuous beneficial effect.     

Effect of surfactant on respiratory failure associated with thoracic aneurysm surgery

OBJECTIVE: To study the effects of surfactant administration on the left lung after surgical repair of descending aortic aneurysms on postoperative respiratory failure. DESIGN: Randomized, prospective, controlled study. SETTING: Clinical investigation. PATIENTS: Eleven patients with respiratory failure associated with thoracic aneurysm surgery. INTERVENTION: Eleven adult patients with acute respiratory failure (PaO2/FIO2 <300 torr [<40 kPa]) after surgical repair of descending aortic aneurysms. The artificial surfactant (30 mg/kg) was given to the operated side of the lung by intrabronchial instillation in six patients (surfactant group), whereas nothing was instilled in the other five patients (control group). MEASUREMENTS AND MAIN RESULTS: Hemodynamic parameters, blood gas, and peak inspiratory pressure were measured at the end of surgery, before surfactant instillation, and at 2, 6, 12, 24, and 48 hrs after surfactant instillation. At the end of surgery, the mean +/- SEM values of the PaO2/FIO2 ratio were 204 +/- 25 torr (27.2 +/- 3.3 kPa) in the surfactant group and 240 +/- 26 torr (32.0 +/- 3.5 kPa) in the control group. After 2, 6, 12, and 48 hrs, improvements in the PaO2/FIO2 ratios were observed in the surfactant group, whereas the control group showed no improvement. Two hours after surfactant instillation, the mean value in the PaO2/FIO2 ratio was significantly higher in the surfactant group (318 +/- 24 torr [42.4 +/- 3.2 kPa]) (p < .05) compared with the control group values (240 +/- 34 torr [32 +/- 4.5 kPa]). CONCLUSION: Surfactant administration immediately after surgery restored gas exchange in postoperative respiratory failure associated with thoracic aneurysm surgery.     

Muscle oxygenation trends during constant work rate cycle exercise in men and women

Chronic bacterial colonization of the lungs, with an excessive inflammatory response, is the major cause of morbidity and mortality in cystic fibrosis. Lung surfactant exhibits a spectrum of potential immunomodulatory properties: phospholipid components inhibit cellular inflammatory responses, whereas the hydrophilic surfactant proteins A (SP-A) and D (SP-D) are integral components of the innate host defense response of the lungs against bacterial infection. Consequently, alteration to the relative proportions of lung surfactant components may alter the susceptibility of the lungs to bacterial colonization. In this study, bronchoalveolar lavage (BAL) samples were collected at diagnostic fiberoptic bronchoscopy from 11 control children, 13 children with cystic fibrosis, and 11 children with acute lung infection. Electrospray ionization mass spectrometry analysis demonstrated negligible changes to the molecular species or total BAL concentrations of phosphatidylcholine, phosphatidylglycerol, or phosphatidylinositol among the three subject groups. In contrast, median SP-A concentration was decreased (P < 0.001) in the cystic fibrosis group (2.65 microg/ml) compared with control (12.35 microg/ml) and infection (9.76 microg/ml) groups. Median SP-D was also decreased (P < 0.05) in the infection (12.17 ng/ml) compared with the control group (641 ng/ml), and was below assay limits for the majority of cystic fibrosis children (P < 0. 001). This dramatic decrease of hydrophilic surfactant proteins in the presence of normal surfactant phospholipid may be one mechanism underlying the relative ineffectiveness of the cellular inflammatory response in killing invading bacteria in the lungs of patients with cystic fibrosis.     

The circulating adhesion molecules sICAM-1 and sP-selectin in patients with sepsis

AIM: The aim of this study was to investigate whether the plasma levels of the circulating adhesion molecules sICAM-1 and sE-selectin could serve as early predictors of developing sepsis and its severity. METHODS: Twenty-four patients admitted to an intensive care unit with a high risk of developing septic complications were enrolled in this study. Patients were divided into three groups: group I, with infection without systemic sepsis, n = 8; group II, surviving patients with severe sepsis and multi-organ failure (MOF), n = 8; and group III, nonsurviving patients with severe sepsis and MOF, n = 8. Classification of patients was performed according to the clinical criteria defined by the Sepsis Consensus Conference in 1992. Blood samples were taken at 7 a.m. starting from the day of admission until the 7th day after diagnosis of sepsis. Plasma levels of sICAM-1 and sE-selectin were determined in all samples taken between the 3rd pre-septic day and the 7th day after the diagnosis of sepsis was made. RESULTS: In group I, both sICAM-1 (354.21 +/- 128.60 ng/ml, 86 samples) and sE-selectin (30.41 +/- 7.20 ng/ml, 86 samples) levels remained within the reference range over the whole period of observation. The sICAM-1 levels of group II (between 550.82 +/- 275.67 ng/ml and 445.08 +/- 243.63 ng/ml) tended to show values above the reference range without being significant. Mean sICAM-1 levels in group II did not differ from those of group I. From the 2nd pre-septic day onwards the sICAM-1 levels of group III increased, but not significantly. Significant differences in sICAM-1 levels between group I and group III were observed, with peaks at the samples of the 2nd preseptic day and after the 3rd day of sepsis, respectively (P < 0.05). The sE-selectin levels in group II were elevated from the 3rd preseptic day onwards, with a peak value on the 2nd day of sepsis (P < 0.05). Afterwards, levels decreased to initial values despite ongoing sepsis. Mean values of sE-selectin levels of group I and II were significantly different with the onset of sepsis (P < 0.05). Plasma levels of sE-selectin in group III were significantly elevated (66.30 +/- 9.00 ng/ml on the 3rd pre-septic day), reaching their maximal values of 106.67 +/- 21.66 ng/ml at the end of the observation period. Significant differences between sE-selectin levels of groups I and III existed from the 3rd pre-septic day onwards, and between group II and III on the 7th and 8th day of sepsis. CONCLUSION: Our results show that sICAM-1 is a relatively non-specific indicator for sepsis. In contrast, sE-selectin seems to be a good and early predictor of the beginning of severe sepsis with MOF. Furthermore, sE-selectin levels seem to have a prognostic value for the severity, possible course, and outcome of developing sepsis.     

Isolated lung perfusion with melphalan and tumor necrosis factor for metastatic pulmonary adenocarcinoma

BACKGROUND: Isolated left lung perfusion with melphalan and human tumor necrosis factor-alpha for pulmonary metastatic adenocarcinoma in the WAG/Rij rat was studied. METHODS: Survival was determined for melphalan, human tumor necrosis-alpha. Lung, pulmonary effluent, and serum melphalan were analyzed by chromatography after isolated lung perfusion or intravenous injection. On day 0, rats were injected with 2.0 x 10(6) CC531S cells intravenously. On day 7, rats underwent sham thoracotomy, received melphalan intravenously, or underwent isolated left lung perfusion with saline, melphalan, tumor necrosis factor, and a combination of the latter two. On day 14, tumor nodules were counted. RESULTS: For the doses of 400 microg tumor necrosis factor, 1,000 microg tumor necrosis factor, or both melphalan and tumor necrosis factor (2 mg + 200 microg), survival rates after contralateral pneumonectomy were 33%, 17%, and 80%, respectively. Survival in all other groups was 100%. Left lung melphalan level was significantly higher after isolated lung perfusion compared to intravenous administration. Significantly fewer left lung nodules were found for 0.5 mg isolated lung perfusion with melphalan (28+/-17) compared to isolated administration (200+/-0) (p = 0.001), and for 1.0 mg intravenous lung perfusion with melphalan (16+/-10) compared to controls (171+/-65) (p = 0.00047). Tumor necrosis factor showed no significant effect. CONCLUSIONS: Isolated lung perfusion with melphalan is an effective treatment for pulmonary metastases from adenocarcinoma in the rat.     

Inhaled nitric oxide therapy for pulmonary disease in pediatrics

Prostaglandin E2 (PGE2) is an anabolic agent of bone in vivo but the mechanism of its action still remains unclear. The aim of this study was to determine whether the effect of PGE2 on skeleton is mediated by pituitary hormones. Forty female, Sprague-Dawley rats were divided into four groups: baseline control (basal), age-matched intact control (CON), hypophysectomy (HX), and HX + PGE2 (2 mg/kg/day) with 10 animals in each group. The basal group was sacrificed at 2 months of age, and the remaining groups after 6 weeks of treatment. Cancellous and cortical bone histomorphometry was performed on double fluorescent-labeled 40 micron-thick sections of the proximal tibia and tibial shaft. Our results show that HX resulted in a cessation of bone growth, a decrease in cancellous bone volume, and cortical bone gain compared with the age-matched, intact CON rats. Compared with the HX group, the HX + PGE2 group had a significantly greater tibial bone density (mean +/- SE, HX + PGE2:1.595 +/- 0.007 versus HX:1.545 +/- 0.013), percent cancellous bone volume (21.4 +/- 2.0 versus 8.41 +/- 1.70), percent cortical bone area (87.2 +/- 0.85 versus 81.7 +/- 0.7), and ratio of cortical area to marrow area (7.14 +/- 0.56 versus 4.52 +/- 0.21). Increased bone masses by PGE2 in the HX animals were accompanied by an increase in the trabecular and endosteal-labeled surface and bone formation rate. The trabecular number and width were increased whereas trabecular separation was decreased in the HX + PGE2 group compared with the HX group (P < 0.05). PGE2 treatment also caused a decrease in the tibial endosteal eroded surface and medullar cavity of the HX animals. In conclusion, this study clearly demonstrates that PGE2 (2 mg/kg/day) in the HX rats increases both cortical and cancellous bones and improves trabecular architecture in the tibia after 6 weeks of treatment. These skeletal alterations are due to a stimulation of bone formation and a suppression of bone resorption activity. These findings suggest that the anabolic effect of PGE2 in bone is independent of pituitary hormones.     

Lyme disease--on the basis of our observations

We biologically assessed functions of several reconstituted surfactants with the same minimum surface tension (2-3 mN/m) as "complete" porcine pulmonary surfactant (natural surfactant) but with longer surface adsorption times. Administration of natural surfactant (adsorption time 0.29 s) into the lungs of surfactant-deficient immature rabbits brought a tidal volume of 16.1 +/- 4.4 (SD) ml/kg during mechanical ventilation with 40 breaths/min and 20 cmH2O insufflation pressure. In static pressure-volume recordings, these animals showed a lung volume of 62.4 +/- 9.7 ml/kg at 30 cmH2O airway pressure and maintained 55% of this volume when the pressure decreased to 5 cmH2O. With two reconstituted surfactants consisting of synthetic lipids or isolated lipids from porcine lungs plus surfactant-associated hydrophobic proteins (adsorption times 0.57 and 0.78 s, respectively), tidal volumes were < 38% of that with natural surfactant (P < 0.05), but static pressure-volume recordings were not different. Care is therefore needed in estimating the in vivo function of surfactant preparations from minimum surface tension or static pressure-volume measurements.     

Bacteremic pneumococcal pneumonia: bone marrow release and pulmonary sequestration of neutrophils

OBJECTIVES: Neutrophils have been implicated in the pathogenesis of acute lung injury in bacteremic pneumococcal pneumonia. The characteristics of the population of neutrophils that injure the lung are still not known. This study was designed to compare the bone marrow release and lung sequestration of neutrophils during bacteremic pneumococcal pneumonia with nonbacteremic pneumonia and isolated bacteremia. DESIGN: Prospective, controlled, experimental study. SETTING: University research laboratory. SUBJECTS: Female New Zealand white rabbits (n = 17; weight 2.3 to 2.7 kg). INTERVENTIONS: The rabbits were pretreated with intravenous 5'-bromo-2-deoxyuridine (BrdU 100 mg/kg i.v.) to pulse label dividing neutrophils in the bone marrow. Twenty hours after the treatment with BrdU, the rabbits were anesthetized and pneumonia was induced by instilling Streptococcus pneumoniae (1.5 x 10(9) organisms) into the lower lobe of the lung. Four hours after pneumonia, bacteremia was induced by infusing S. pneumoniae (3.0 x 10(9) organisms) into the circulation (pneumonia + bacteremia: n = 6). These animals were compared with those with just pneumonia (n = 5) or bacteremia (n = 6). MEASUREMENTS AND MAIN RESULTS: White blood cell, neutrophil, and differential count. BrdU-labeled neutrophils (neutrophilBrdU) were identified using immunohistochemistry. Cells in tissues were examined microscopically, using sequential level stereologic analysis. The pneumonia + bacteremia group developed a leukopenia (7.3 +/- 0.7 to 2.4 +/- 0.2 x 10(9)/L) following the bacteremia that was associated with an increase in circulating band cells and neutrophilBrdU (2.3 +/- 0.8% to 33.5 +/- 2.8%) which were both higher than those in the other groups (p < .005). Bone marrow smears showed accelerated maturation of neutrophils in the pneumonia + bacteremia group (neutrophilBrdU increased from 11.6 +/- 1.0 to 45.3 +/- 2.1%). Morphometric studies of the lung showed increased neutrophil sequestration in the untreated lung tissue of the pneumonia + bacteremia group (16 +/- 0.8 x 10(8)/mL tissue) compared with the pneumonia (6.6 +/- 0.3 x 10(8)/mL tissue) and bacteremia (12 +/- 0.6 x 10(8)/mL tissue) groups (p < .0001). NeutrophilBrdU preferentially sequester in the lungs of all groups but were slow to migrate into the alveolar air spaces (p < .05). CONCLUSIONS: During bacteremic pneumococcal pneumonia there is an accelerated maturation of neutrophils in the bone marrow with an enhanced release of neutrophils into the circulation. These newly released neutrophils preferentially sequester in lung microvessels but are slow to migrate into the alveolar air space.     

Bioaccumulation and retention of lead in the mussel Mytilus galloprovincialis following uptake from seawater

PURPOSE: We compared two groups of risk patients to try to identify different radiologic patterns in pulmonary tuberculosis. MATERIALS AND METHODS: 74 subjects, divided into two groups (HIV+:27; HIV-:47) were included since 1993. The patients were examined with chest X-ray (CXR) and CT. RESULTS: In the HIV+ group we observed 40 radiologic alterations, with 6 cases of bilateral lung involvement and 9 of atypical localizations; particularly: 11 consolidations, 8 cavitations, 5 miliary diseases, 9 hilar or mediastinal adenopathies, 3 extrapulmonary localizations and 4 negative CXRs. In the HIV- group we found 53 radiologic alterations, with 6 cases of bilateral lung involvement and 3 of atypical localizations; particularly: 12 consolidations, 25 cavitations, 5 nodular patterns, 1 miliary disease, 5 nodal disease, 4 pleural diseases and 1 negative CRX. DISCUSSION AND CONCLUSIONS: In HIV- patients lung consolidations and tysiogen patterns are significantly prevalent, while miliary diseases, mediastinal diseases and atypical localizations and negative CRXs are more frequent in HIV+ patients. We found miliary diseases, mediastinal diseases and extrapulmonary localizations also in HIV- patients with heavily impaired social, economic and sanitary conditions. This alterations indicate compromised host resistance, independent of the causes and modalities of immunodeficiency. The distinction between primary and secondary tuberculosis is currently not mandatory.     

The influence of the milieu on the rate of neutralisation of herpes simplex virus 1

Minimizing secondary injury after severe traumatic brain injury (TBI) is the primary goal of cerebral resuscitation. For more than two decades, hyperventilation has been one of the most often used strategies in the management of TBI. Laboratory and clinical studies, however, have verified a post-TBI state of reduced cerebral perfusion that may increase the brain's vulnerability to secondary injury. In addition, it has been suggested in a clinical study that hyperventilation may worsen outcome after TBI. OBJECT: Using the controlled cortical impact model in rats, the authors tested the hypothesis that aggressive hyperventilation applied immediately after TBI would worsen functional outcome, expand the contusion, and promote neuronal death in selectively vulnerable hippocampal neurons. METHODS: Twenty-six intubated, mechanically ventilated, isoflurane-anesthetized male Sprague-Dawley rats were subjected to controlled cortical impact (4 m/second, 2.5-mm depth of deformation) and randomized after 10 minutes to either hyperventilation (PaCO2 = 20.3 +/- 0.7 mm Hg) or normal ventilation groups (PaCO2 = 34.9 +/- 0.3 mm Hg) containing 13 rats apiece and were treated for 5 hours. Beam balance and Morris water maze (MWM) performance latencies were measured in eight rats from each group on Days 1 to 5 and 7 to 11, respectively, after controlled cortical impact. The rats were killed at 14 days postinjury, and serial coronal sections of their brains were studied for contusion volume and hippocampal neuron counting (CA1, CA3) by an observer who was blinded to their treatment group. Mortality rates were similar in both groups (two of 13 in the normal ventilation compared with three of 13 in the hyperventilation group, not significant [NS]). There were no differences between the groups in mean arterial blood pressure, brain temperature, and serum glucose concentration. There were no differences between groups in performance latencies for both beam balance and MWM or contusion volume (27.8 +/- 5.1 mm3 compared with 27.8 +/- 3.3 mm3, NS) in the normal ventilation compared with the hyperventilation groups, respectively. In brain sections cut from the center of the contusion, hippocampal neuronal survival in the CA1 region was similar in both groups; however, hyperventilation reduced the number of surviving hippocampal CA3 neurons (29.7 cells/hpf, range 24.2-31.7 in the normal ventilation group compared with 19.9 cells/hpf, range 17-23.7 in the hyperventilation group [25th-75th percentiles]; *p < 0.05, Mann-Whitney rank-sum test). CONCLUSIONS: Aggressive hyperventilation early after TBI augments CA3 hippocampal neuronal death; however, it did not impair functional outcome or expand the contusion. These data indicate that CA3 hippocampal neurons are selectively vulnerable to the effects of hyperventilation after TBI. Further studies delineating the mechanisms underlying these effects are needed, because the injudicious application of hyperventilation early after TBI may contribute to secondary neuronal injury.     

Evaluation of lung function after intratracheal perfluorocarbon administration in healthy animals

OBJECTIVES: To investigate the effects of partial liquid ventilation (i.e., mechanical ventilation in combination with intratracheal administration of perfluorocarbon) on lung function, with particular attention to the integrity of the alveolocapillary membrane in healthy adult animals. DESIGN: Prospective, randomized, controlled study. SETTING: Laboratory at the Department of Experimental Anesthesiology, Erasmus University Rotterdam. SUBJECTS: Ten adult male New Zealand rabbits. INTERVENTIONS: Five rabbits were intratracheally treated with 12 mL/kg of perfluorocarbon while conventional mechanical ventilation (volume-controlled, tidal volume of 12 mL/kg, respiratory rate of 30 breaths/min, inspiration/expiration ratio of 1:2, positive end-expiratory pressure of 2 cm H2O, and an FIO2 of 1.0) was applied for 3 hrs. To assess the permeability of the alveolocapillary membrane, pulmonary clearance of inhaled technetium-99m-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA) measurements were performed at 3 hrs and compared with data from the control group (n = 5) treated with mechanical ventilation only, using the same ventilatory parameters. MEASUREMENTS AND MAIN RESULTS: Pulmonary gas exchange and lung mechanical parameters were measured in both groups at 30-min intervals. Mean values for PaO2 in the perfluorocarbon group, although at adequate levels, were less than those values of the control group during the 3-hr study period (370 +/- 44 vs. 503 +/- 44 torr at 3 hrs [49.3 +/- 5.9 vs. 67.1 +/- 5.9 kPa]). Peak and mean airway pressures were higher in the perfluorocarbon group (ranging from 1.9 to 3.4 cm H2O and 0.7 to 1.3 cm H2O, respectively) compared with the control group, while end-inspiratory airway pressure was similar in both groups. The half-life of 99mTc-DTPA was 83.7 +/- 24.5 mins in the control group, which was significantly longer (p < .01) than in the perfluorocarbon group (49.8 +/- 6.1 mins). CONCLUSIONS: These findings suggest that partial liquid ventilation with perfluorocarbons lowers pulmonary gas exchange in healthy animals, and the increased pulmonary clearance of 99mTc-DTPA after 3 hrs of this type of ventilatory support may reflect minimal reversible changes in the lung surfactant system.     

Differences in responses to norepinephrine and adenosine triphosphate in isolated, perfused mesenteric vascular beds between normotensive and spontaneously hypertensive rats

OBJECT: Although nitric oxide (NO) has been shown to play an important role in the pathophysiological process of cerebral ischemia, its contribution to the pathogenesis of traumatic brain injury (TBI) remains to be clarified. The authors investigated alterations in constitutive nitric oxide synthase (NOS) activity after TBI and the histopathological response to pharmacological manipulations of NO. METHODS: Male Sprague-Dawley rats underwent moderate (1.7-2.2 atm) parasagittal fluid-percussion brain injury. Constitutive NOS activity significantly increased within the ipsilateral parietal cerebral cortex, which is the site of histopathological vulnerability, 5 minutes after TBI occurred (234.5+/-60.2% of contralateral value [mean+/-standard error of the mean ?SEM?], p < 0.05), returned to control values by 30 minutes (114.1+/-17.4%), and was reduced at 1 day after TBI (50.5+/-13.1%, p < 0.01). The reduction in constitutive NOS activity remained for up to 7 days after TBI (31.8+/-6.0% at 3 days, p < 0.05; 20.1+/-12.7% at 7 days, p < 0.01). Pretreatment with 3-bromo-7-nitroindazole (7-NI) (25 mg/kg), a relatively specific inhibitor of neuronal NOS, significantly decreased contusion volume (1.27+/-0.17 mm3 [mean+/-SEM], p < 0.05) compared with that of control (2.52+/-0.35 mm3). However, posttreatment with 7-NI or pre- or posttreatment with nitro-L-arginine-methyl ester (L-NAME) (15 mg/kg), a nonspecific inhibitor of NOS, did not affect the contusion volume compared with that of control animals (1.87+/-0.46 mm3, 2.13+/-0.43 mm3, and 2.18+/-0.53 mm3, respectively). Posttreatment with L-arginine (1.1+/-0.3 mm3, p < 0.05), but not 3-morpholino-sydnonimine (SIN-1) (2.48+/-0.37 mm3), significantly reduced the contusion volume compared with that of control animals. CONCLUSIONS: These data indicate that constitutive NOS activity is affected after moderate parasagittal fluid percussion brain injury in a time-dependent manner. Inhibition of activated neuronal NOS and/or enhanced endothelial NOS activation may represent a potential therapeutic strategy for the treatment of TBI.     

Surgical resection for hepatocellular carcinoma in Cape Town--a clinical and histopathological study

BACKGROUND: The effect of mycophenolate mofetil (MMF) and sirolimus (rapamycin, RAPA) mono- and combination-therapy was examined in prevention of acute heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat. METHODS: Both drugs were administered orally for up to 30 days. Eleven groups (n=6) were involved in the first part of the heart allografting model. Brown Norway (RT1n) to Lewis (RT1(1)) combination was used in the heart and pancreas transplantation models, whereas Buffalo (RT1b) to Wistar Furth (RT1u) was used in the kidney transplantation model. RESULTS: The naive control group showed a mean survival time of 6.5+/-0.6 days. There were graded dose-responses to monotherapy of MMF 10 and 20 mg(kg/ day (12.5+/-2.6 days; 19.3+/-9.0 days) and RAPA 0.2, 0.4, 0.8, and 1.8 mg/kg/day (19.2+/-2.0 days; 30.0+/-7.3 days; 50.8+/-12.5 days; 51.2+/-2.6 days), respectively (P=0.001). Results with the combined use of drugs indicate that a synergistic or very strong synergistic interaction was produced when compared with monotherapy of MMF or RAPA: MMF 10 mg(kg/day+RAPA 0.2 mg/kg(day (52.7+/-5.7 days, combination index [CI] =0.189), MMF 20 mg(kg/day+RAPA 0.2 mg/kg/day (57.7+/-5.7 days, CI=0.084), MMF 10 mg/kg/day+RAPA 0.4 mg(kg/day (50.2+/-13.5 days, CI=0.453), and MMF 20 mg/kg(day+ RAPA 0.4 mg/kg(day (51.5+/-6.8 days, CI=0.439), respectively. These results were repeatable in the prevention of acute pancreas and kidney allograft rejection in the rat. In the second part of the study of reversal of ongoing acute heart allograft rejection model, the combined treatment of MMF 10 mg/kg(day+RAPA 0.2 mg/ kg(day (35.5+/-16.0 days, CI=0.794) and MMF 20 mg/kg day+RAPA 0.2 mg(kg/day (57.2+/-4.7 days, CI=0.310) represented synergistic interaction compared with monotherapy of MMF or RAPA. CONCLUSIONS: Concomitant therapy of MMF and RAPA produces a synergistic effect in prevention of heart, pancreas, and kidney allograft rejection and in reversal of ongoing heart allograft rejection in the rat.     

Approach to density-functional ionization energy

BACKGROUND: For patients with malignant neoplasms metastatic to lung, systemic chemotherapy in doses high enough to achieve significant survival improvement is often limited by host toxicity. Isolated single-lung perfusion offers the advantage of delivering high-dose organ-specific chemotherapy while minimizing systemic toxicity. We compared the cardiac and systemic toxicities associated with intravenous administration versus isolated single-lung perfusion with doxorubicin. METHODS: Thirty-three male Fischer 344 rats weighing 275 to 300 g were randomized into three groups: normal control rats (n = 11), intravenous doxorubicin (7/mg/kg) (n = 11), and isolated left lung perfusion with 320 micrograms doxorubicin/mL (n = 11). Animals undergoing isolated single-lung perfusion were anesthetized with pentobarbital, intubated, and ventilated, and then had left thoracotomy with cannulation of the pulmonary artery and a pulmonary venotomy; pulmonary artery and vein were clamped proximally. Animals were perfused for 10 minutes at a rate of 0.5 mL/min, followed by a 5 minute rinse with buffered hespan solution. Arteriotomy and venotomy were repaired and circulation was restored. Daily weights were recorded. On day 24, cardiac output was determined in all groups by injection of radiolabeled chromium 51 microspheres. RESULTS: Animals treated with 7 mg/kg intravenous doxorubicin had a significant weight loss as compared with those treated with isolated lung perfusion (209.2 +/- 29.9 g versus 302.3 +/- 10.1 g; p < 0.01). Animals treated with isolated single-lung perfusion, after recovering from surgical stress, resumed normal growth pattern. Significant cardiac toxicities were seen in intravenously treated animals; cardiac index (27.4 +/- 6.9 versus 39.4 +/1 6.3 mL/min/100g body weight and heart weights (0.56 +/- 0.04 versus 0.88 +/- 0.09 g) were reduced in the intravenously treated group as compared with the group treated with isolated single-lung perfusion. In addition, severe hematologic toxicities are associated with intravenous doxorubicin administration. CONCLUSIONS: Intravenous administration of doxorubicin is associated with severe host toxicities, which include weight loss, decreased cardiac function, and hematologic toxicity. Isolated lung perfusion with high-dose doxorubicin is well tolerated and is associated with minimal host toxicity.     

In vivo cyclin E expression as a marker for early cervical neoplasia

BACKGROUND: Heat shock has been associated with the acquisition of tolerance to a wide variety of stressful conditions, including ischemia. This is partly mediated by the production of various heat shock proteins (HSP), including HSP70. One novel approach to the reduction of ischemia-reperfusion injury after lung transplantation is the induction of HSP70 by heat pretreatment of the donor. The purpose of this study was to investigate the feasibility of this approach in an animal model of lung transplantation. METHODS: Animals were divided into six main groups, with groups I to III representing transplanted animals: In groups I and II, donor animals were anesthetized and then underwent heat stress 6 and 12 hours before organ harvest, respectively. Control animals underwent general anesthesia but no heat stress. After harvest, left lungs from groups I to III were preserved for 18 hours at 40 degrees C and then implanted into isogeneic recipients, which were killed 24 hours after reperfusion to assess graft function. Group IV and V animals underwent heat stress followed by a recovery period of 6 and 12 hours, respectively. Lungs were collected both at the time of harvest (right lungs) and after 18 hours of cold preservation (left lungs). Group VI served as nontransplanted controls. Groups IV to VI did not undergo lung transplantation. RESULTS: At the time of harvest but before implantation, HSP70 was significantly increased in heat-shocked nontransplanted donor lungs (groups IV and V) compared with group VI controls. After 18 hours of cold preservation, HSP70 levels were higher in group IV compared with group V and group VI controls. At 24 hours after reperfusion, mean arterial oxygenation was significantly higher in group I compared with group II and group III controls (290.25+/-24.5 vs 154.5+/-23.9 and 119.6+/-11.3 mm Hg, respectively; P < .001). Myeloperoxidase activity was improved in group I compared with group III controls (0.048+/-0.018 vs 0.137+/-0.036 deltaOD/mg/min, respectively; P < .05). The wet/dry weight ratio was also improved in group I compared with group III controls (6.2+/-0.3 vs. 7.8+/-0.4, respectively; P < .05). CONCLUSIONS: Heat pretreatment of the donor 6 hours before harvest results in increased synthesis of HSP70, which offers a dramatic protective effect against subsequent ischemia-reperfusion injury in the lung isograft.     

Effects of surfactant distribution and ventilation strategies on efficacy of exogenous surfactant

The effects of both surfactant distribution patterns and ventilation strategies utilized after surfactant administration were assessed in lung-injured adult rabbits. Animals received 50 mg/kg surfactant via intratracheal instillation in volumes of either 4 or 2 ml/kg. A subset of animals from each treatment group was euthanized for evaluation of the exogenous surfactant distribution. The remaining animals were randomized into one of three ventilatory groups: group 1 [tidal volume (VT) of 10 ml/kg with 5 cmH2O positive end-expiratory pressure (PEEP)]; group 2 (VT of 5 ml/kg with 5 cmH2O PEEP); or group 3 (VT of 5 ml/kg with 9 cmH2O PEEP). Animals were ventilated and monitored for 3 h. Distribution of the surfactant was more uniform when it was delivered in the 4 ml/kg volume. When the distribution of surfactant was less uniform, arterial PO2 values were greater in groups 2 and 3 compared with group 1. Oxygenation differences among the different ventilation strategies were less marked in animals with the more uniform distribution pattern of surfactant (4 ml/kg). In both surfactant treatment groups, a high mortality was observed with the ventilation strategy used for group 3. We conclude that the distribution of exogenous surfactant affects the response to different ventilatory strategies in this model of acute lung injury.     

The role of oxygen free radicals in acute renal failure complicating obstructive jaundice: an experimental study

Oxidant injury is considered to be an important mechanism in the pathophysiology of acute renal failure. It has been thought that decrease in extracellular and intracellular fluid and endotoxemia seen in obstructive jaundice may cause an increase in production of oxygen free radicals and impairment in antioxidant defense mechanism. This study is designed to investigate the possible role of oxidant injury in renal failure seen in jaundiced patients. In this study, 28 rats were divided into four groups: Control (C)(N = 7); Renal ischemia (RI)(N = 7); Obstructive jaundice+renal ischemia (OJ+RI)(N = 7); Obstructive jaundice (OJ)(N = 7). All groups were compared with each other according to renal failure findings and enzyme activities, such as Xanthine oxidase (XOD), Superoxide Dismutase (SOD) and Catalase in renal cortex and Glutathione Peroxidase (GSH-Px), in blood at 3rd day after ischemia and reperfusion. Renal failure findings monitored by blood urea and creatinine levels, seemed more evident in OJ+RI than RI group (p < 0.05). When compared with RI, in OJ+RI group, increase in XOD activity at 3rd day was statistically significant [0.259 +/- 0.01 U/g (tissue) and 0.362 +/- 0.03 U/g (tissue) respectively] (p < 0.05). SOD and GSH-Px activities of each ischemic group at 3rd day were decreased compared to non-ischemic groups. This fall was significant (p < 0.05). But there was no statistical difference between jaundiced and non-jaundiced groups. Alterations in catalase activities also had no statistical significance. These findings may suggest that the injury induced by oxygen free radicals at re-oxygenation of tissue after ischemia may also play a role in the pathogenesis of acute renal failure developed in obstructive jaundice.     

Clinical significance of CMV-specific T helper responses in lung transplant recipients

BACKGROUND: Cytomegalovirus (CMV) disease continues to be a major problem for lung transplant patients who generate an inefficient immune response to control this viral infection. Both T helper and cytotoxic T cells are thought to play an important role in prevention and control of CMV disease. We investigated the clinical significance of CMV-specific memory responses in lung transplant recipients. METHOD: Peripheral blood samples (140) were collected from 99 lung transplant recipients. Patients were grouped according to their pre-transplant CMV serological status as recipient/donor (R-/D+, 25 patients), 28 R+/D+ patients, 35 R+/D- patients and 11 R-/D- patients. Memory responses to CMV whole antigen, 5 CMV proteins, and tetanus toxoid (TT) were measured in a 6-day proliferative assay. Results were expressed as the stimulation index (SI = experimental cpm/background cpm), and were considered positive if the SI was >3 and the cpm values were over 1,000. RESULTS: The frequency of positive CMV memory responses was similar in three groups: 64% for R-/D+, 63% for R+/D+ and 56% for R+/D- except for R-/D- (21%). The memory response to TT was similar for all four groups (70% of samples were positive). The level of responsiveness to individual CMV proteins was much higher in R+/D+ group (65%) than the other two groups (35% for R+/D-, and 31% for R-/D+). We determined the temporal relationship between the presence of CMV-specific memory responses and the diagnosis of CMV disease. In the R-/D+ group, 16 of 17 patients who had CMV disease eventually developed CMV-specific memory. In those patients (n = 3) who failed to develop CMV-specific T helper response for a prolonged time, all had recurrent CMV disease. In the R+/D+ group, 4 of 8 patients with CMV disease exhibited CMV-specific memory responses. Three of 4 patients in whom we observed a persistent absence of CMV-specific memory had multiple episodes of CMV pneumonitis. In the R+/D- group, only one of 4 patients with CMV disease had suppressed CMV-specific memory response after first episode of CMV pneumonitis and had recurrent disease. CONCLUSION: In lung transplant recipients, the loss or persistent lack of CMV-specific memory following infection was associated with chronic CMV disease. These data suggest that monitoring T helper memory responses following primary CMV infection or after augmented immunosuppression for treatment of rejection may identify those patients at risk for morbidity associated with recurrent CMV disease.     

Alterations in glucose metabolism in patients with Alzheimer's disease

OBJECTIVE: To determine the alterations in glucose metabolism that occur in patients with Alzheimer's Disease (AD). DESIGN: Cross-sectional comparison of AD and healthy controls. SETTING: A University teaching hospital. PATIENTS: Healthy controls (n = 14, BMI: 24.9 +/- 0.5 kg/M2, age 73 +/- 1 years) and patients with AD (n = 12, BMI: 23.9 +/- 1.0 kg/M2, age 72 +/- 1 years). All controls and patients with AD had a normal history and physical examination, a negative family history of diabetes, and took no medications. MEASUREMENTS: All patients and controls underwent an assessment of their dietary intake and physical activity, a 3-hour oral glucose tolerance test (OGTT), and a 2-hour hyperglycemic glucose clamp study. RESULTS: Total caloric intake (AD: 27.1 +/- 1.3 kcal/kg/day; Control: 23.6 +/- 1.6 kcal/kg/day; P = ns) and intake of complex carbohydrates (AD: 5.9 +/- 0.4 kcal/kg/day; Control: 6.5 +/- 0.3 kcal/kg/day; P = ns) were not different between groups. Leisure time physical activity was greater in controls (AD: 2970 +/- 411 kcal/week; Control: 5229 +/- 864 kcal/week; P < 0.05). Patients with AD had higher fasting glucose (AD: 5.9 +/- 0.2 mmol/L; Control: 5.1 +/- 0.1 mmol/L; P < 0.01) and insulin (AD: 144 +/- 20 pmol/L; Control: 100 +/- 6 pmol/L; P < 0.05) values. In response to the OGTT, the area under the curve for glucose and insulin was similar in both groups. During the hyperglycemic clamp, steady-state glucose values were higher in the Alzheimer's patients (AD: 11.5 +/- 0.2 mmol/L; Control: 10.9 +/- 0.1 mmol/L, P < 0.01). First- and second-phase insulin responses were similar in each group. The insulin sensitivity index (units: mL/kg.min per pmol/L x 100), a measure of tissue sensitivity to insulin, was reduced in the patients with AD (AD: 0.59 +/- 0.06; Control: 0.79 +/- 0.07; P < 0.05). CONCLUSIONS: We conclude that early AD is characterized by alterations in peripheral glucose metabolism, which may relate, in part, to alterations in physical activity.