Epidemic mortality of the sponge Ircinia variabilis (Schmidt, 1862) associated to proliferation of a Vibrio bacterium.

In recent years, several episodes of mass mortality of sessile epibenthic invertebrates, including sponges, have been recorded worldwide. In the present study, we report a disease event on Ircinia variabilis recorded in September 2009 along the southern Adriatic and Ionian seas (Apulian coast), with the aim to quantify the mortality incidence on the sponge population, to investigate the effect of the disease on the sponge tissues and to assess whether the disease is associated with vibrios proliferation. The injured sponges showed wide necrotic areas on the surface or disruption of the body in several portions. Necrotic areas were whitish and often were covered with a thin mucous coat formed by bacteria. In the most affected specimens, sponge organisation resulted partial or complete loss, with the final exposure of the dense skeletal network of spongine fibres to the environment. The results of microbiological cultural analysis using in parallel Marine Agar 2216 and thiosulphate/citrate/bile salts/sucrose agar demonstrated that, in affected specimens, vibrios represented 15.8 % of the total I. variabilis surface culturable bacteria. Moreover, all the isolated vibrios, grown from the wide whitish areas that characterize the surface of the diseased sponges, were identified, and their assignment to the Vibrio rotiferianus was consistent with phylogenetic analysis and data of morphological, cultural and biochemical tests. Studies on V. rotiferianus have shown that its pathogenicity, with respect to various aquatic organisms, is higher than that of Vibrio harveyi. The factors triggering the disease outbreak in Ircinia variabilis populations remain unclear. At present, we can hypothesize the involvement in the disease of a synergetic mechanism that, under stressful physiological conditions (high temperature, elevated nutrients and reduced water flow), induces sponge pathogens, in our case V. rotiferanius, to become virulent, making sponges unable to control their proliferation. Additional studies are needed to understand the etiological processes as well as the factors involved in sponges recovering from this epidemic event allowing them to face mass mortality. A drastic reduction of sponge-specific representatives could have marked a negative impact on the environmental health on account of their role in the sea remediation processes as filter-feeding organisms.

Maintenance therapy with gefitinib after first-line chemotherapy in patients affected by advanced non-small cell lung cancer.

BACKGROUND: Chemotherapy extends life for patients with advanced non-small cell lung cancer (NSCLC). Second-line treatment of NSCLC includes the use of cytotoxic drugs; however, toxicity is of concern. One molecular target for lung cancer is the epidermal growth factor receptor (EGFR). Gefitinib (Iressa) is an EGFR inhibitor. The aim of our study was to evaluate time to progression (TTP), overall survival (OS) and toxicities in a population affected by NSCLC using Iressa as maintenance therapy after first-line chemotherapy. PATIENTS AND METHODS: Thirty patients were enrolled with stable disease or partial response. Six cycles of a platinum-based first-line chemotherapy were administered. Iressa was administered at the dose of 250 mg/d. RESULTS: Median TTP was 5 months; median overall survival was 8 months. TTP for adenocarcinoma and non-adenocarcinoma patients was 10 months and 3.2 months, respectively. No toxic effects were seen in 80% of the patients; 17% of the patients had grade 1 follicolitis. OS for adenocarcinoma and non-adenocarcinoma patients were 15 and 5.9 months, respectively. CONCLUSION: Gefitinib could be an ideal second-line therapy for adenocarcinoma patients responding to first-line chemotherapy.

Effect of chemotherapy on somatostatin receptor detection with octreotide scintigraphy in hormone-refractory prostate cancer patients.

BACKGROUND: Neuroendocrine cells have been found in all stages of prostate cancer. Neuroendocrine differentiation of prostate adenocarcinoma is a possible target for therapeutic strategies, such as administration of GH analogs (e.g., somatostatin), especially in patients with hormone-refractory prostate cancer (HRPC). The presence of receptors for these drugs in tumor cells and tissues is essential and is assessed with 111In-octreotide scintigraphy (Octreoscan). The relationship between these receptors and chemotherapy, the new standard therapy for HRPC, is unknown. PATIENTS AND METHODS: 111In-octreotide scintigraphy was performed on 20 patients affected by HRPC, all with metastatic disease. Chemotherapy with a single agent was also administered to all patients. RESULTS: In 63% of the patients, all metastases were negative to Octreoscan. Several metastases were positive in 37% of patients only, compared to 94% previously described in a chemotherapy-naive population. CONCLUSION: Chemotherapy seemed to reduce the cellular receptors for somatostatin analogs.

Chemoimmunotherapy with low dose vinorelbine and interleukin-2 in treatment of patients with metastatic renal cell carcinoma.

Systemic therapies employed in patients with metastatic renal cell carcinoma (MRCC) include chemotherapy to immunomodulatory cytokines (interleukin 2 [IL-2], interferon alpha [INFalpha]), chemoimmunotherapy, adoptive immune therapy and anti-angiogenic therapy. Despite this range of treatment alternatives, the optimal therapy for MRCC patients is far from being established. Thus, attempts with novel therapeutic approaches implementing new drug combinations are justified. We conducted a phase II evaluation of a combination of vinorelbine and IL-2, both at low doses, in 30 patients with MRCC. The rationale of the combination was to damage the tumor tissue to the extent necessary to make it more immunogenic while, at the same time, to obtain an efficient immune response through the concomitant administration of IL-2. The treatment, given in different dose combinations and administration times, resulted feasible, with no renal, neurological or hematological toxicity. The overall survival of the whole group of patients is higher than that usually observed following treatment with immunotherapies (18.2 versus 13.3 months, respectively). While the limited number of treated patients does not allow advancing conclusions on the effective activity of the adopted protocol, the results observed are encouraging.

Concurrent chemo-radiotherapy with taxotere and cisplatin in head and neck cancer: a feasibility study.

BACKGROUND: For many years surgery was the cornerstone of treatment for head and neck cancers and radiotherapy was the treatment of choice in adjuvant and advanced inoperable settings. Recently, induction sequential chemotherapy followed by radiotherapy has shown good tolerability and has prolonged the median overall survival. This phase II trial explored the feasibility of the concurrent association with radiotherapy of a full-dose chemotherapy based on an original schedule of docetaxel and cisplatin. PATIENTS AND METHODS: Twenty-four patients with head and neck squamous cell carcinoma (HNSCC) were enrolled. Taxotere (docetaxel) was administered on day 1, weekly for 6 weeks. The dose was 33 mg/m2 /w. Cisplatin was administered on day 2 at the dose of 70 mg/m2. Radiotherapy delivered was 60 Gy divided in 30 administrations over 6 weeks. RESULTS AND CONCLUSION: This schedule of treatment for HNSCC proved feasible. Appropriate support treatment, however, appears to be necessary for the feasibility of this concurrent chemo-radiotherapy.

Cerebral CO2 vasoreactivity evaluation by transcranial Doppler ultrasound technique: a standardized methodology.

OBJECTIVE: In normal subjects cerebral CO2 vasoreactivity is measured during spontaneous hyperventilation, breathholding, or adding CO2 to inspiratory gases. The correlation between CO2 and cerebral blood flow may, however, be invalidated by the effects of a modified respiratory pattern on venous return, sympathovagal balance, and cathecolamine release. Moreover, the duration of the test, usually not considered, may play an important role. This may justify the scattering of values found in literature. We evaluated a new standardized method for overcoming these confounding factors. DESIGN: Experimental. PARTICIPANTS: Twenty-one healthy volunteers. METHODS: Subjects were connected through a mouthpiece to a mechanical ventilator set in the intermittent positive pressure ventilation mode. The ventilator was fed by two 40-1 tanks, one of which contained 5% CO2. The inspiratory CO2 concentration was varied at fixed time intervals from 0% to 5% without modifying ventilator settings. End-tidal CO2 was measured at the mouthpiece. Mean blood velocity (V(m)) and pulsatility index (PI) in the middle cerebral artery were measured by means of transcranial Doppler ultrasound. RESULTS: The test was easily applicable and well tolerated. No hemodynamic alterations were observed during the tests. The correlation between CO2 and V(m) was always linear and highly significant (R2 > 0.8, p < 0.0001). A low intersubject variability was observed. No difference was found between the two hemispheres, nor between the sexes. CONCLUSIONS: The strict standardization of the technique, avoiding hemodynamic interference, may explain the low intersubject variability. The value of this technique in ventilated neurosurgical patients is still speculative, but it might allow the collecting of valuable data together with a reduction in exposure to CO2, and hence cerebral blood flow modifications.

Distribution dynamics of perfluorocarbon delivery to the lungs: an intact rabbit model.

Motivated by the goal of understanding how to most homogeneously fill the lungs with perfluorocarbon for liquid ventilation, we investigate the transport of liquid instilled into the lungs using an intact rabbit model. Perfluorocarbon is instilled into the trachea of the ventilated animal. Radiographic images of the perfluorocarbon distribution are obtained at a rate of 30 frames/s during the filling process. Image analysis is used to quantify the liquid distribution (center of mass, spatial standard deviation, skewness, kurtosis, and indicators of homogeneity) as time progresses. We compare the distribution dynamics in supine animals to those in upright animals for three constant infusion rates of perfluorocarbon: 15, 40, and 60 ml/min. It is found that formation of liquid plugs in large airways, which is affected by posture and infusion rate, can result in a more homogeneous liquid distribution than gravity drainage alone. The supine posture resulted in more homogeneous filling of the lungs than did upright posture, in which the lungs tend to fill in the inferior regions first. Faster instillation of perfluorocarbon results in liquid plugs forming in large airways and, consequently, more uniform distribution of perfluorocarbon than slower instillation rates in the upright animals.

In vitro toxicity of taxol based anticancer drug combinations on human hemopoietic progenitors.

The sequence dependency of the interaction of taxol with other anticancer drugs is of clinical importance, and may be due to pharmacokinetic changes and/or to inherent differences in the sensitivity of target normal or cancer cells. This study presents results on the in vitro interaction of taxol with doxorubicin, cisplatin, etoposide and vinorelbine in alternate sequences on human hemopoietic progenitors (CFU-GM). Peripheral blood mononuclear non adherent cells were exposed to IC50 of Taxol for 24 hours and then, for 1 hour to IC50 of each of the other drugs. In a second set of experiments the reverse sequence was applied. The cell suspension was subsequently cultured to assay the growth of CFU-GM. A strong sequence dependency characterizes the combination taxol-vinorelbine, while for the other combinations the order of sequence appears to have little impact on in vitro toxicity on CFU-GM. Comparing results on CFU-GM with that obtained in vitro with the same combination sequences on cancer cell lines some remarkable differences show up. Studies on a normal human myeloid line may therefore have a place in preclinical evaluation of sequence of anticancer drug combinations.

In vitro toxicity of A 3'-azido-3'-deoxythymidine and hydroxyurea combination on normal myeloid progenitors.

Hydroxyurea (HU) appears to increase 3'-azido-3'-deoxythymidine (AZT) antiretroviral activity and cytotoxicity by inhibiting thymidilate synthesis. The combination of AZT and HU may therefore be of clinical usefulness. We evaluated the in vitro hemotoxicities of different combinations of AZT and HU in comparison with the hemotoxicities exerted by either of the two drugs alone. Peripheral blood granulocyte macrophage committed progenitors (CFU-GM) of healthy donors were selected as targets of hemotoxicity. Both AZT and HU separately had a dose-dependent inhibitory effect on the in vitro growth of normal circulating CFU-GM. The combination of the two drugs induced a statistically significant synergistic cytotoxicity. In fact, addition of HU induced a remarkable reduction of AZT ID50. Thus, future clinical application of AZT, HU combination should take into account the greater hemosuppressive action of the combination in respect to that observed following administration of either drug alone.

Epibiotic Vibrio luminous bacteria isolated from some hydrozoa and bryozoa species.

Luminous bacteria are isolated from both Hydrozoa and Bryozoa with chitinous structures on their surfaces. All the specimens of the examined hydroid species (Aglaophenia kirchenpaueri, Aglaophenia octodonta, Aglaophenia tubiformis, Halopteris diaphana, Plumularia setacea, Ventromma halecioides), observed under blue light excitation, showed a clear fluorescence on the external side of the perisarc (chitinous exoskeleton) around hydrocladia. In the bryozoan Myriapora truncata, luminous bacteria are present on the chitinous opercula. All the isolated luminous bacteria were identified on the basis of both phenotypic and genotypic analysis. The isolates from A. tubiformis and H. diaphana were unambiguously assigned to the species Vibrio fischeri. In contrast, the isolates from the other hydroids, phenotypically assigned to the species Vibrio harveyi, were then split into two distinct species by phylogenetic analysis of 16S rRNA gene sequences and DNA-DNA hybridization experiments. Scanning electron microscopy analysis and results of culture-based and culture-independent approaches enabled us to establish that luminous vibrios represent major constituents of the bacterial community inhabiting the A. octodonta surface suggesting that the interactions between luminous bacteria and the examined hydrozoan and bryozoan species are highly specific. These interactions might have epidemiological as well as ecological implications because of the opportunistic pathogenicity of luminous Vibrio species for marine organisms and the wide-distribution of the hydrozoan and bryozoan functioning as carriers.

Concurrent radio-chemotherapy with docetaxel and cisplatinum in inoperable or relapsed head and neck cancer.

Usually head and neck cancer is treated with combined therapy, applying surgery, if possible, and then radiotherapy and chemotherapy in a sequential or concomitant way. Sequential approach seems to be preferred, because of the high toxicity rate of concomitant therapy. Platinum compounds and 5-fluorouracil are the standard drugs, but new drugs are entering therapeutic arena: gemcitabine and taxanes are the most promising ones. The efficacy of these drugs, especially in association with radiotherapy, must be assessed; moreover it is essential to ascertain how to associate these drugs to radiotherapy and to evaluate drug toxicity when combined with the latter. End point of the study here presented is a preliminar assessment of toxicity and feasibility of concurrent radio-chemoterapy with docetaxel and cisplatinum in patients with head and neck cancer. The number of enrolled patients and the relatively short time of follow up do not allow to evaluate treatment efficacy.

[A method for quantitative evaluation of the physical quality of radiologic devices]. / Un metodo per la valutazione quantitativa della qualità fisica delle apparecchiature radiologiche.

INTRODUCTION: The evaluation of the quality of a radiological device depends on both clinical judgement about diagnostic imaging and physical judgement about technical performance. The latter is the final result of a set of measurements of several physical quantities. The aim of the present paper is to make a synthesis of such measurements through a parameter whose comparison with a threshold value would allow to establish whether a given radiological machine is acceptable from the point of view of physical quality. MATERIAL AND METHODS: The parameter, which we called quality index, was obtained by considering, for each operating condition, the values of physical quantities which exceed their limits and by giving them a different weight, depending on their influence on image quality, patient dose, or both. Further analysis led to assign a gravity index to such quantities as a function of the extent of the discrepancies with respect to their limits. RESULTS AND DISCUSSION: The method was illustrated through the example of a simple radiological equipment with two separate hypothetical cases corresponding to different degrees of fault gravity. The method gave very different values of quality index, according to the extent of discrepancies found in the two cases. We gave suggestions about the way to follow in order to determine a proper threshold value for each kind of equipment. The invariance of the method with respect to the choice of the physical quantities and their limits was also shown. CONCLUSIONS: The proposed method appears to be useful because it makes a synthesis, through a single parameter, of a series of measurements of several physical quantities and allows to discriminate, through direct comparison with a threshold value, about the physical quality of a radiological device; in addition, it may be easily implemented into programs for the automated analysis of quality controls. The quality index may contribute, together with some other parameters to be defined in a forthcoming paper, in establishing a quantitative criterion in order to define equipment replacement priorities within the context of the technological improvement requested by the laws currently in force.

Experimental cisplatin neuronopathy in rats and the effect of retinoic acid administration.

Peripheral nervous system alterations were induced in adult rats by administration of cisplatin (CDDP) 2 mg/kg twice weekly for 4.5 weeks. Dorsal root ganglion neurons showed pathological changes. Morphometric determinations demonstrated a reduction in size of the somatic, nuclear and nucleolar area. The nucleoli were the most involved subcellular structures. Nerve conduction velocity and the tail-flick test for pain were both significantly altered in CDDP treated rats, whereas the rota-rod test for coordination revealed no changes in either treated or control rats. Analytical determinations demonstrated platinum accumulation in the DRG of CDDP treated rats. Spontaneous recovery, demonstrated by morphometric, electrophysiological, functional and analytical determinations, occurred after treatment discontinuation within about 7 weeks. A pilot study of the possible neuroprotective action of retinoic acid (RA) was also performed with this model of cisplatin neuronopathy. The rationale for using RA was based on its assumed antioxidant and neurotrophic effect. However, RA failed to prevent morphometric, electrophysiological, functional and analytical alterations induced by CDDP on DRG neurons. RA induced only a mild generalized protective effect.

The effects of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia.

UNLABELLED: We investigated the effects of body mass index (BMI) on functional residual capacity (FRC), respiratory mechanics (compliance and resistance), gas exchange, and the inspiratory mechanical work done per liter of ventilation during general anesthesia. We used the esophageal balloon technique, together with rapid airway occlusion during constant inspiratory flow, to partition the mechanics of the respiratory system into its pulmonary and chest wall components. FRC was measured by using the helium dilution technique. We studied 24 consecutive and unselected patients during general anesthesia, before surgical intervention, in the supine position (8 normal subjects with a BMI < or = 25 kg/m2, 8 moderately obese patients with a BMI >25 kg/m2 and <40 kg/m2, and 8 morbidly obese patients with a BMI > or = 40 kg/m2). We found that, with increasing BMI: 1. FRC decreased exponentially (r = 0.86; P < 0.01) 2. the compliance of the total respiratory system and of the lung decreased exponentially (r = 0.86; P < 0.01 and r = 0.81; P < 0.01, respectively), whereas the compliance of the chest wall was only minimally affected (r = 0.45; P < 0.05) 3. the resistance of the total respiratory system and of the lung increased (r = 0.81; P < 0.01 and r = 0.84; P < 0.01, respectively), whereas the chest wall resistance was unaffected (r = 0.06; P = not significant) 4. the oxygenation index (PaO2/PAO2) decreased exponentially (r = 0.81; P < 0.01) and was correlated with FRC (r = 0.62; P < 0.01), whereas PaCO2 was unaffected (r = 0.06; P = not significant) 5. the work of breathing of the total respiratory system increased, mainly due to the lung component (r = 0.88; P < 0.01 and r = 0.81; P < 0.01, respectively). In conclusion, BMI is an important determinant of lung volumes, respiratory mechanics, and oxygenation during general anesthesia with patients in the supine position. IMPLICATIONS: The aim of this study was to investigate the influence of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia.

Cardiac, skeletal, and ocular abnormalities in patients with Marfan's syndrome and in their relatives. Comparison with the cardiac abnormalities in patients with kyphoscoliosis.

Polygraphic (including apexcardiograms and carotid pulse tracings) and M mode echocardiographic examinations were carried out in 34 symptomatic patients with Marfan's syndrome; similar studies were performed in 32 relatives and in 34 young patients with kyphoscoliotic disease. The purpose of these investigations was to determine the association between cardiac and oculoskeletal abnormalities and to identify specific patterns of disease with a poor prognosis. Polygraphic tests showed significant changes in all patients with Marfan's syndrome: 74% showed the apical systolic click and murmur of mitral valve prolapse; 48% had the diastolic murmur of aortic regurgitation; isolated mitral valve prolapse was found in 52%, 26% had isolated aortic regurgitation, and 22% had a combination of the two. Echocardiographic changes were also found in all patients: 79% had aortic root dilatation; 48% fluttering of the anterior mitral leaflet; 79% mitral valve prolapse, mostly pansystolic; 34% both mitral prolapse and aortic root dilatation; and 34% left ventricular dilatation. The severities of the cardiac and oculoskeletal abnormalities were not correlated. The high prevalence of mitral valve prolapse found in these patients, which did not vary with age or sex, was also present in their relatives: mitral prolapse was present in 38% and aortic dilatation, with or without regurgitation, in 14%. Four of the relatives had clearcut Marfan's syndrome, and at least four others a forme fruste. The metacarpal index was abnormal in 41% of the relatives; ocular abnormalities were rare. In kyphoscoliotic patients only an increase in the prevalence of mitral prolapse (18.2% in women, none in men) was found. These findings underline a complex pattern of association between cardiac, ocular, and skeletal abnormalities in patients with Marfan's syndrome and confirm an appreciable inheritability of several of the markers of the disease.

Splenectomy induced complete remission in a patient with multicentric Castleman's disease and autoimmune hemolytic anemia.

Castleman's disease (CD) is a rare disorder of the lymphoid tissue in which the clinical manifestations often mimic a malignant lymphoma. Despite the absence of monoclonality of the lymphoid proliferation, the multicentric variant of the disease (MCD) is characterized by severe symptoms and poor prognosis. Etiologic, pathogenetic, and therapeutic aspects of MCD are still uncertain. We report the case of a 57-year-old patient affected by MCD complicated by severe immunohemolytic anemia. Whereas the clinical and laboratory response to steroids and chemotherapeutic agents was only partial, splenectomy induced a complete remission of hemolysis and disappearance of the constitutional symptoms and of all generalized lymphadenopathies.

Positive end-expiratory pressure improves respiratory function in obese but not in normal subjects during anesthesia and paralysis.

BACKGROUND: Morbidly obese patients, during anesthesia and paralysis, experience more severe impairment of respiratory mechanics and gas exchange than normal subjects. The authors hypothesized that positive end-expiratory pressure (PEEP) induces different responses in normal subjects (n = 9; body mass index < 25 kg/m2) versus obese patients (n = 9; body mass index > 40 kg/m2). METHODS: The authors measured lung volumes (helium technique), the elastances of the respiratory system, lung, and chest wall, the pressure-volume curves (occlusion technique and esophageal balloon), and the intraabdominal pressure (intrabladder catheter) at PEEP 0 and 10 cm H2O in paralyzed, anesthetized postoperative patients in the intensive care unit or operating room after abdominal surgery. RESULTS: At PEEP 0 cm H2O, obese patients had lower lung volume (0.59 +/- 0.17 vs. 2.15 +/- 0.58 l [mean +/- SD], P < 0.01); higher elastances of the respiratory system (26.8 +/- 4.2 vs. 16.4 +/- 3.6 cm H2O/l, P < 0.01), lung (17.4 +/- 4.5 vs. 10.3 +/- 3.2 cm H2O/l, P < 0.01), and chest wall (9.4 +/- 3.0 vs. 6.1 +/- 1.4 cm H2O/l, P < 0.01); and higher intraabdominal pressure (18.8 +/-7.8 vs. 9.0 +/- 2.4 cm H2O, P < 0.01) than normal subjects. The arterial oxygen tension was significantly lower (110 +/- 30 vs. 218 +/- 47 mmHg, P < 0.01; inspired oxygen fraction = 50%), and the arterial carbon dioxide tension significantly higher (37.8 +/- 6.8 vs. 28.4 +/- 3.1, P < 0.01) in obese patients compared with normal subjects. Increasing PEEP to 10 cm H2O significantly reduced elastances of the respiratory system, lung, and chest wall in obese patients but not in normal subjects. The pressure-volume curves were shifted upward and to the left in obese patients but were unchanged in normal subjects. The oxygenation increased with PEEP in obese patients (from 110 +/-30 to 130 +/- 28 mmHg, P < 0.01) but was unchanged in normal subjects. The oxygenation changes were significantly correlated with alveolar recruitment (r = 0.81, P < 0.01). CONCLUSIONS: During anesthesia and paralysis, PEEP improves respiratory function in morbidly obese patients but not in normal subjects.

An improved in vivo rat model for the study of mechanical ventilatory support effects on organs distal to the lung.

OBJECTIVE: To study the influence of different mechanical ventilatory support strategies on organs distal to the lung, we developed an in vivo rat model, in which the effects of different tidal volume values can be studied while maintaining other indexes. DESIGN: Prospective, randomized animal laboratory investigation. SETTING: University laboratory of Ospedale Maggiore di Milano-Instituto di Ricovero e Cura a Carattere Scientifico. SUBJECTS: Anesthetized, paralyzed, and mechanically ventilated male Sprague-Dawley rats. INTERVENTIONS: Two groups of seven rats each were randomized to receive tidal volumes of either 25% or 75% of inspiratory capacity (IC), calculated from a preliminary estimation of total lung capacity. Ventilation strategies for the two groups were as follows: a) 25% IC, 9.9+/-0.8 mL/kg; frequency, 59+/-4 beats/min; positive end-expiratory pressure, 3.6+/-0.8 cm H2O; and peak inspiratory airway pressure (Paw), 13.2+/-2 cm H20; and b) 75% IC, 29.8+/-2.9; frequency, 23+/-13; positive end-expiratory pressure, 0; peak inspiratory Paw, 29.0+/-3. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure (invasively monitored) remained well above adequate perfusion pressure values throughout, and no significant difference was seen between the two groups. PaO2, pHa, and PaCO2 values were compared after 60 mins of ventilation and again, no significant difference was seen between the two groups (PaO2, 269+/-25 and 260+/-55 torr; pHa, 7.432+/-0.09 and 7.415+/-0.03; PaCO2, 35.4+/-8 and 32.5+/-2 torr, for the 25% IC and 75% IC groups, respectively). Mean Paws were not different (6.4+/-0.8 cm H2O in the 25% IC groups, and 6.1+/-1.2 in the 75% IC groups, respectively). At the end of the experiment, animals were killed and the liver and kidney isolated, fixed in 4% formalin, cut, and stained for optic microscopy. Kidneys from rats ventilated with 75% IC showed increased Bowman's space with collapse of the glomerular capillaries. This occurred in a greater percentage of rats ventilated with 75% IC (0.67+/-0.2 vs. 0.29+/-0.2, 75% IC vs. 25% IC, respectively; p < .05). Perivascular edema was also present in rats ventilated with 75% IC (p < .05). Morphometric determinations of the empty zones (index of edema) demonstrated a trend toward differences between 75% IC livers and 25% IC (0.14+/-0.05 vs. 0.11+/-0.02, respectively). CONCLUSION: We conclude that it is possible to study the effects of mechanical ventilatory support on organs distal to the lung by means of an in vivo rat model.