In vivo assessment of left ventricular remodelling after myocardial infarction by digital video contrast angiography in the rat

OBJECTIVE

The aim was to develop a digital video contrast angiographic method for assessing global left ventricular function and volume in vivo in the rat and then to apply it to a study of ventricular remodelling after coronary occlusion, with and without reperfusion.

METHODS

Digital contrast angiography was performed on 29 rats, including the following groups: sham operated (n = 11), non-transmural myocardial infarction produced by reperfusion (n = 8), and transmural infarction produced by permanent occlusion (n = 10). Under anaesthesia three weeks later, biplane fluoroscopic images were acquired following venous contrast injection. Levophase images were digitised, and left ventricular end diastolic and end systolic volumes and ejection fractions were obtained using an area-length method. Left ventricular ejection fraction data also were calculated by videodensitometry from video density curves.

RESULTS

Compared to the sham operated group, the reperfused group showed a significant decrease in left ventricular ejection fraction, at 53(SD 7) v 70(5)% (p < 0.01), and an increase in end diastolic volume. The permanent occlusion group showed a further decrease in the ejection fraction [40(8)%] and a further significant increase in end diastolic volume compared to the reperfused group (p < 0.01). Left ventricular ejection fraction correlated inversely with percent infarct size (r = 0.882) and showed a positive correlation with the spared epicardial area (r = 0.721). Most haemodynamic variables, including maximum left ventricular dP/dt, failed to discriminate between the groups. The methods showed reasonable accuracy when tested in vitro using contrast filled balloons. In vivo, the left ventricular ejection fraction calculated by densitometry showed adequate interobserver variability (2 SD +/- 8.5 percentage points), but the area-length method showed somewhat more scatter.

CONCLUSIONS

Digital video contrast angiography is a feasible method for the assessing global left ventricular function in the rat and should be useful in other small animal models. Significant differences in left ventricular volumes and ejection fractions were detected between reperfused and permanent occlusion groups, whereas haemodynamic variables showed non-significant trends. Reperfusion after 45 min of occlusion caused sparing of the epicardium, prevented unfavourable remodelling, and improved the ejection fraction compared to permanent occlusion.

Cardiac involvement of progressive muscular dystrophy (Becker type, Limb-girdle type and Fukuyama type) evaluated by radionuclide method

Tl-201 SPECT and Tc-99m-Human serum albumin (HSA) multigated radionuclide ventriculography were performed on 11 patients with progressive muscular dystrophy (Becker type 2, Fukuyama type 2, Limb-girdle type 7) to evaluate myocardial involvement. Hypoperfusion was detected in 8 patients on Tl-201 SPECT. Decreases in both systolic function (left ventricular ejection fraction; LVEF) and diastolic function (peak filling rate; PFR) were also seen in these patients. A high incidence of myocardial involvement of these kinds of progressive muscular dystrophy was suggested.

Immobilized anti-TCR mAb induces split functions in a CD8+ CTL clone

A signal through the T cell receptor (TCR) without a second costimulatory signal provided by antigen-presenting cell (APC) generally causes a state of anergy in CD4+ T helper (Th) 1 cells, but not in CD4+ Th2 cells. In contrast, less is known about anergic CD8+ T cells. We have examined whether a CD8+ cytotoxic T lymphocyte (CTL) clone incapable of producing IL-2 could be rendered into a state of unresponsiveness by treatment with immobilized anti-TCR mAb in the absence of a secondary stimulation. The CD8+ CTL clone was induced into nonproliferative response to subsequent antigen stimulation while it was bound to immobilized anti-TCR mAb. The immobilized anti-TCR mAb-treated CTL clone also failed to significantly produce cytokine with antigen stimulation. In contrast, the ability of the CTL clone to specifically lyse target cells was apparently retained. The results suggest that there might be intracellular signal pathways via the TCR for CTL functions such as proliferative response, cytokine production, and CTL killing.

Elastin cross-linking in the skin from patients with amyotrophic lateral sclerosis

Two cross-links unique to elastin, desmosine and isodesmosine were measured and compared in skin tissue (left upper arm) from 10 patients with amyotrophic lateral sclerosis (ALS) and from seven age-matched controls. The contents of desmosine and isodesmosine were significantly decreased (p < 0.01 and p < 0.01, respectively) in patients with ALS compared with those of controls, and were negatively and significantly associated with duration of illness in ALS patients (r = -0.77, p < 0.01 and r = -0.65, p < 0.05, respectively). The decline in skin desmosine and isodesmosine is more rapid in ALS than in normal ageing. Thus cross-linking of skin elastin is affected in ALS.

Preferential usage of the Fc receptor gamma chain in the T cell antigen receptor complex by gamma/delta T cells localized in epithelia

zeta and eta chains of the T cell antigen receptor (TCR) complex and the gamma chain of Fc receptors (FcR gamma) constitute a family of proteins important for the expression of, and signal transduction through, these receptors in hematopoietic cells. In zeta-deficient mice, TCR expression was reduced in most T cells. By contrast, CD8 alpha alpha + TCR-gamma/delta + intestinal intraepithelial lymphocytes in these mice expressed a normal level of TCR. Biochemical analysis of the TCR complex in these cells from zeta-deficient as well as normal mice revealed the predominant usage of FcR gamma. Furthermore, gamma/delta + T cells in epithelia of the skin and female reproductive organs from zeta-deficient mice also showed relatively high TCR expression, indicating the usage of FcR gamma. These observations demonstrate the preferential usage of FcR gamma by gamma/delta + T cells localized in epithelia of normal mice.

Bone morphogenetic protein-induced muscle- and synovium-derived cartilage differentiation in vitro

Muscle- and synovium-derived mesenchymal-type cells differentiated into cartilage in response to a coating of partially purified rabbit bone morphogenetic protein (BMP) on a substratum of plastic. Observed by means of phase contrast microscopy, light microscope histochemistry, and electron microscopy, the sequence of events on a BMP-coated plastic substratum is the same as that observed on a substratum of bone matrix. The plastic eliminates the possibility of any endogenous allogeneic matrix-derived BMP contaminating the system. The differentiation of cartilage from synoviocytes and subsynovial cells resembles the pathologic process occurring in human chondromatosis.

Suppression of anti-tumor CD4+ T cell responsiveness in the tumor-bearing state and its recovery in in vitro culture free of tumor burden

We investigated whether the responsiveness of anti-tumor CD4+ T cells suppressed in the tumor-bearing state is reversed in conditions free of tumor burden. Spleen cells from BALB/c mice bearing a syngeneic tumor (CSA1M) 1-3 wk after inoculation with CSA1M cells produced interleukin-2 (IL-2) and IL-4 upon in vitro culture without addition of exogenous tumor antigens. This lymphokine production was achieved through collaboration between anti-CSA1M CD4+ T cells and antigen-presenting cells (APC) that had been pulsed with CSA1M tumor antigens in vivo in the tumor-bearing state. However, spleen cells from late (8-10 wk) tumor-bearing stages produced reduced levels of lymphokine production despite the presence of comparable proportions of CD4+ T cells. Because APC in these cell populations exhibited enhanced capacities to present tumor antigens, reduced responsiveness was ascribed to the dysfunction of CD4+ T cells themselves. When spleen cells from early tumor-bearing mice were preincubated for 1-2 days and recultured in fresh medium, the magnitude of lymphokine production by these cells was not changed. In contrast, the same protocol of preincubation and reculture for cells from late tumor-bearing mice resulted in the recovery of anti-tumor lymphokine-producing capacity. The recovered capacity was comparable to or slightly higher than that expressed by cells from early tumor-bearing stages. Since the CD4+ T cell content did not significantly differ before and after preincubation, enhanced lymphokine production was due to the recovered responsiveness of anti-tumor CD4+ helper T cells. The recovery of anti-tumor responsiveness was also induced in vivo by tumor removal at the late tumor-bearing stage: spleen cells from mice 2-4 wk after tumor resection efficiently produced IL-2 and IL-4. These results indicate that the immunodysfunction of anti-tumor CD4+ T cells induced in the tumor-bearing state is reversible because release from tumor burden either by preincubation in vitro or by tumor removal in vivo results in almost complete recovery of the potent anti-tumor responsiveness initially expressed.

[Changes in right ventricular hemodynamic function by unilateral pulmonary arterial occlusion test]

We performed unilateral pulmonary arterial occlusion test (UPAO) for the preoperative evaluation of lung function in patients undergoing lung resection. In this test, the main pulmonary artery of either side is occluded to simulate postoperative functional status. In order to evaluate the right ventricular hemodynamic function, we measured right ventricular ejection fraction (RVEF) and right ventricular end-diastolic volume index (RVEDVI) throughout UPAO by thermodilution method. We investigated the relationships between changes in right ventricular hemodynamic function and postoperative complications related to cardiac functions, namely arrhythmias or heart failure. Thirty-four patients without heart disease prior to lung resection were examined by UPAO, and RVEF and RVEDVI were measured. Analyses demonstrated that changes in RVEF were inversely correlated with changes in RVEDVI. In 6 cases, RVEDVI increased from control by over 20% during UPAO. All of these patients had postoperative cardiac complications. The hypothetical ventricular function curves showed a large increase in RVEDVI relative to right ventricular stroke work index (RVSWI), suggesting a decrease in right ventricular function. In conclusion, these results suggest that changes in RVEDVI during UPAO may predict postoperative cardiac complications in patients undergoing pulmonary resection.

Increased expression of cofilin in dystrophic chicken and mouse skeletal muscles

A monoclonal antibody (McAb) specific for actin depolymerizing factor (ADF) was prepared. With this and previously prepared anti-cofilin McAb (MAB-22) and other antibodies, the expression of cofilin and ADF in the muscles of dystrophic (NH-413) chicken and dystrophic (C57BL/6J dy/dy) mice was compared with that in normal control animals by immunoblotting and immunocytochemical methods. Since cofilin expression is down-regulated during normal postnatal development of skeletal muscles [Abe et al. (1989) J. Biochem. 106, 696-702], cofilin was detected in the breast (pectoralis) muscle of normal adult chicken and the leg (femoris and tibialis anterior) muscles of normal mice only at a low level. ADF was not detectable in adult skeletal muscles. However, a significant increase of cofilin amount, but not of ADF amount, was observed in these muscles of the dystrophic animals, when the symptom of muscular dystrophy became evident. In order to localize cofilin in individual muscle fibers, serial cryosections of the dystrophic chicken muscle were examined with anti-cofilin antibody (MAB-22). The antibody stained cells of different size in the dystrophic muscle, indicating that cofilin expression was induced in the regenerating muscle cells as well as in the pre-existing myofibers. We suggest that cofilin is involved in disassembly or reorganization of actin in the dystrophic muscle.

Inactivation of peptidoleukotrienes in the isolated perfused rat lung

Inactivation of peptidoleukotrienes by alveolar transfer and metabolism was investigated in isolated perfused rat lungs. [3H]Leukotriene (LT)C4 or [3H]LTE4 was instilled into the airways and 25 min later the distribution of tritiated metabolites in bronchoalveolar lavage fluid, lung, and perfusate was determined. Metabolism of LTC4 was found to occur in both the alveolar and vascular space in contrast to metabolism of LTE4, which occurred exclusively on the alveolar side. The alveolar transfer of leukotrienes into the perfusate was slow with only 25-29% transfer occurring during the 25-min perfusion. Only a small percentage of instilled LTC4 was transferred out of the airways unmetabolized, suggesting that this leukotriene is not the major one that is removed from the airways. In contrast, LTE4 either added directly into the airways or produced in the alveolar space from LTC4 metabolism was more readily transferred out of the lung. LTE4 was transported into alveolar cells by a nonenergy requiring, receptor-mediated mechanism inhibited by LTD4/LTE4 receptor antagonists and by probenecid. Cysteine-containing compounds (cysteine, cystine, and N-acetylcysteine) added to the perfusate caused a significant increase in LTE4/N-acetyl-LTE4 transport possibly due to a coupling of cyst(e)ine (in) and LTE4 (out) transport. Metabolism of LTC4 by gamma-glutamyltransferase appears to be the rate limiting step of peptidoleukotriene inactivation in the rat airways, being necessary for both metabolic inactivation and the formation of products which can be eliminated by transfer.

Collagen fibril diameter and its relation to cross-linking of collagen in the skin of patients with amyotrophic lateral sclerosis

The diameter of collagen fibrils and the age-related, stable cross-link, histidinohydroxylysinonorleucine (HHL), of skin tissue (left biceps) were measured and compared in 11 patients with amyotrophic lateral sclerosis (ALS) and 7 controls. In ALS patients, it was found that (1) the diameter of collagen fibrils and the content of HHL were negatively and significantly associated with the duration of illness (r = -0.74, P < 0.01 and r = -0.72, P < 0.02, respectively), and (2) there was an appreciable positive correlation between the diameter of collagen fibrils and the content of HHL (r = 0.73, P < 0.02). These findings were not observed in controls. These suggest there is a close relationship between the decreased amount of HHL and the small diameter of collagen fibrils in ALS.

Selective MR angiography of the liver

OBJECTIVE

Two-dimensional time-of-flight MR angiography was done with a 1.0 T whole-body imaging system.

METHODS

The 10 mm thick presaturation slab was positioned between two sagittal imaging slices of the liver. Images were obtained through the right lobe of the liver by moving the slab and slices together. Each image was acquired during a breath-holding interval of 16 s.

RESULTS

Since the directions of the portal and hepatic venous flows are opposite to each other in the right lobe, these two venous systems could be visualized on separate images by the interleaved presaturation slab. On the reconstructed angiograms, separation between the two venous systems was complete and even the fourth and fifth branches were demonstrated clearly. These images facilitate clear understanding of the structure of the intrahepatic blood vessels.

CONCLUSION

Although this technique is limited to volunteer studies and works only on the right lobe of the liver, it will provide valuable information for evaluating the location and vascular involvement in various liver diseases.

[Transcranial Doppler monitor in the case of selective cerebral perfusion]

Six patients underwent ascending aorta and aortic arch replacement for aneurysmal disease between 1991.12-1992.2 using the cardiopulmonary bypass technique with selective cerebral perfusion from right axillary artery. For four patients, intraoperative transcranial Doppler monitorings of left MCA flow velocity were done. We added left carotid artery perfusion for 5 patients because of old age; 1, intraoperative finding of anisocoria; 1 and low left MCA flow velocity on the TCD monitor; 3. After the addition of left side perfusion, the left MCA flow velocity on the TCD monitor recovered to normal level in the 3 patients. TCD reflected the cerebral perfusion state every minutes and seemed to be very useful monitor in selective cerebral perfusion. It also suggested that unilateral cerebral perfusion does not supply enough blood flow in contralateral side of brain in many cases. To another patient who also underwent aortic arch replacement, we examined preoperatively left MCA flow velocity on the TCD monitor under left carotid artery compression. This "carotid artery compression test" was thought to suggest the degree of right to left intracranial collateral blood flow via Willis's circle. TCD image, when the left carotid artery was clamped, was compared with the result of preoperative "carotid artery compression test". But we can't evaluate the results quantitatively now.

[Treatment of cancer by intraperitoneal infusion of anticancer drugs using an anti-adhesion sheet connected with a subcutaneously implanted reservoir]

Intraperitoneal infusion of anticancer drugs via a catheter fitted with a subcutaneously implanted reservoir, when repeated frequently, usually becomes increasingly more difficult to perform owing to the catheter's becoming more and more clogged. Moreover, intraperitoneally administered anticancer drugs give rise to severe intestinal adhesions, which in turn interfere with rapid, even and widespread diffusion of the infused drugs in the peritoneal cavity. With the aim of overcoming the difficulties and inconveniences with conventionally used apparatuses for the intraperitoneal administration of drugs, we tentatively manufactured a new apparatus for intraperitoneal drug infusion. A special protective sheet, devised by Tanaka, for the prevention of postoperative intestinal adhesion following abdominal surgery, is connected with a reservoir to be implanted in the subcutis. The apparatus is inserted into the peritoneal cavity of gastric patients with peritoneal dissemination to allow it to remain in place therein. Treatment with anticancer drugs administered intraperitoneally with the use of this device proved apparently more successful than without it, resulting in improvement of QOL, disappearance of ascites, shrinkage in the size of tumor mass and depressed serum levels of a tumor marker, CA 19-9. The sheet was thus found to have the advantages of permitting safe repeated administration of anticancer drugs, even and extensive drug delivery to the peritoneal cavity, sampling of intraperitoneal cancer cells and ascitic fluid without inconvenience, and easy-to-perform continual infusion of anticancer drugs at the outpatient service.

[Regional cerebral blood flow in the patients with closed-head injury using 123I-IMP SPECT and computed tomography]

123I-IMP SPECT and CT were evaluated in 20 patients with closed-head injury. The detected focal lesions by both examinations were 36. Twenty lesions (55.6%) were seen on both CT and SPECT, and SPECT revealed larger abnormality than CT. Sixteen (44.4%) of 36 lesions were seen only on SPECT. Regional cerebral blood flow (r-CBF) of thirty-one focal lesions were quantified by reference sampling method and compared to r-CBF of the patients without neurological problem. r-CBF of 18 localized lesions accordant with low density area (LDA) on CT were significantly lower than those of 13 lesions seen only on SPECT. And r-CBF of both lesions were significantly lower than that of control patients. Regional cerebral blood flow on the areas with visually normal RI uptake were also significantly lower than that of control group. Regardless of CT findings, some disturbance of r-CBF was considered in patients with head trauma. Therefore the quantification of r-CBF with 123I-IMP SPECT was a useful method for evaluating functional change in those patients.

[Hydraulic conductivity of visceral pleura in dogs]

We measured the hydraulic conductivity of the visceral pleura in seven mongrel dogs in situ. The left chest was opened at the seventh intercostal space. A hemispherical capsule, filled with physiological saline, was attached to the visceral pleura of the left lower lobe by the negative pressure in the plate, using a vacuum pump. Transpleural fluid flow (V) was measured at different intracapsular pressures (delta P). The hydraulic conductivity was calculated from the relation between fluid flow and intracapsular pressure, i.e., the slope of the linear regression line. The hydraulic conductivity was 1.49 +/- 0.68 (mean +/- SD) nL.min-1 x cmH2O-2. Our values were smaller than those of former reports obtained in vivo. It is suggested that the dynamics mechanisms of plural effusion may be clarified by studies using our method.

[The boundary levels of laboratory data in autoimmune diseases]

The clinical significance of rheumatoid factor, antinuclear antibody, anti-thyroid antibody, CH50 and serologic tests for syphilis (STS) in boundary levels were investigated. The boundary levels were tentatively determined as: RF 5-20 U/ml, ANA 20-40X, anti-thyroid antibody 100-400X and CH50 25-30 U/ml. In STS, cases with biological false positive reaction were examined. In ninety percent of patients with positive anti-thyroid antibody, thyroid antibody, thyroid diseases were demonstrated. However, various disorders were involved at the boundary levels of rheumatoid factor, antinuclear antibody, CH50 and serologic tests for syphilis. To assess the boundary levels of these serological data, it seems important to observe serial data and other clinical and laboratory findings.

Degeneration of anterior horn cell in neuronal type of Charcot-Marie-Tooth disease (hereditary motor and sensory neuropathy type II): a Golgi study

A morphological study using the Golgi impregnation method was carried out on the anterior horn cells at cervical (C), thoracic (Th), and lumbar (L) levels of the spinal cord in a patient with neuronal type of Charcot-Marie-Tooth disease (hereditary motor and sensory neuropathy type II) and an age-matched control. The present study demonstrated an uneven cell body surface, loss of cells (particularly large cells), loss of dendrites, reduced dendritic extent and an irregular surface and shape of dendrites at the C and L levels. In contrast, hematoxylin and eosin and Klüver-Barrera staining showed only simple atrophy or no change. The Th level of the patient showed none of these changes. Our results suggest that the degeneration or loss of dendrites of anterior horn cells by the Golgi staining method, which is most severe at the L level, is closely related to clinical findings such as muscle atrophy and weakness in neuronal type of Charcot-Marie-Tooth disease.

[ST-T changes associated with severe hypoxia in a case of obstructive sleep apnea syndrome]

A 59-year-old man with obesity was admitted with nocturnal dyspnea and nocturnal precordial oppression. Catheter data disclosed no cardiac failure. Polysomnography was performed for a total of 3 nights. The diagnosis of obstructive sleep apnea syndrome was made because apnea index was 50 times/hour in average, the max apnea time was about 80 seconds and disappearance of airflow during decrease of endoesophageal pressure was observed. At the max apnea time, ST-T change in leads V2-5 was observed with severe desaturation (arterial oxygen saturation: 49%). It was considered that myocardial hypoxia following sleep apnea might be the cause of nocturnal precordial oppression.

Bone and 67Ga scintigraphy in the evaluation of rib lesions in patients with multiple myeloma

Rib lesions in 14 patients with multiple myeloma were evaluated by 99mTc-phosphorous compound bone scintigraphy and 67Ga scintigraphy. In the present study, in order to accurately detect rib lesions in multiple myeloma, bone and 67Ga scintigraphy were performed in 14 patients with multiple myeloma. The patterns of radionuclide accumulation in rib lesions on bone scintigraphy were classified by their grade, type, and site, and the findings were compared with the results of 67Ga scintigraphy. Thus, in cases of multiple myeloma, it was important to consider carefully both the intensity and the design of bone scintigraphy in combination with follow-up study by 67Ga scintigraphy. As a result of such consideration, we found that bone and 67Ga scintigraphy were useful in distinguishing invasive lesions from benign degenerative changes in the rib cage in cases with suspected rib involvement of multiple myeloma.

Protective effect of R(-)-1-(benzo[b]thiophen-5-yl)- 2-[2-(N,N-diethylamino)ethoxy]ethanol hydrochloride (T-588), a novel cerebral activator, against experimental cerebral anoxia

Effects of R(-)-1-(benzo[b]thiophen-5-yl)-2-[2- (N,N-diethylamino)ethoxy]ethanol hydrochloride (T-588) on normobaric hypoxia, histotoxic anoxia by KCN and complete ischemia by decapitation were investigated in mice. T-588 (30-100 mg/kg, p.o.) showed a significant and dose-dependent prolongation of the survival time in all of the models studied. Bifemelane (100-300 mg/kg, p.o.) was also protective against all the models. Tacrine was protective against hypoxia but had no effect on anoxia and ischemia. Imipramine was protective against anoxia, but shortened the survival time of hypoxic mice. It had no effect on ischemia. The anti-hypoxic effect of T-588 was completely inhibited by pretreatment with scopolamine (1 mg/kg, i.p.), while the anti-anoxic effect was partially inhibited. Its effect on the ischemia was not affected by scopolamine. Hypoxia decreased the cerebral contents of ATP, phosphocreatine and glucose and increased the contents of lactate in mice. T-588 had no effect on these changes. Bifemelane prolonged pentobarbital-induced sleeping time in mice with the doses inducing anti-anoxic action, but T-588 did not. These results suggest that the activation of the CNS cholinergic system is involved as one of the mechanisms for the anti-anoxic action of T-588.

Time-course of left atrial performance during coronary artery occlusion followed by reperfusion in anesthetized dogs by densitometric analysis of digital atrioventriculographic images

The left atrial (LA) function during coronary artery occlusion followed by reperfusion using densitometric analysis of digital atrioventriculographic images was evaluated. Eight anesthetized dogs underwent atrioventriculography at baseline, 10 and 60 min after left circumflex coronary artery (LCX) occlusion and 5, 30, 60, and 120 min of reperfusion. Time-density curves were obtained for LA and left ventricle (LV). The ratios of passive atrial video-densitometric change (VC) to total VC (Passive Ratio), and active VC to total VC (Active Ratio) were calculated. Left ventricular ejection fraction (LVEF), peak ejection rate (PER), and peak filling rate (PFR) were derived. Active Ratio, an index of atrial contraction, increased to 144%, and Passive Ratio decreased to 75% of baseline at 60 min of LCX occlusion. Two hours after reperfusion, both Active and Passive Ratios returned to control level. While LVEF reduced to 70%, PER to 67%, LV peak positive dP/dt to 88% of baseline at 60 min after occlusion, and remained depressed at 2 h after reperfusion. However, PFR, LV peak negative dP/dt and LV isovolumic pressure decay rate showed recovery at 2 h after reperfusion. There were significant correlations between PFR and Passive Ratio (r = 0.41), and between Active and Passive Ratios (r = 0.55). Thus, time-course of recovery of LV post-ischemic systolic and diastolic function was different. Return of LA function to control level during 2 h after reperfusion may be depend on recovery of LV diastolic function.

Endotoxin priming followed by high altitude causes pulmonary edema in rats

Rapid ascent to high altitude may be associated with the development of high-altitude pulmonary edema (HAPE) in susceptible individuals. Because lung lavage fluid obtained from such patients can be rich in protein and neutrophils, we considered that an element of lung injury and inflammation contributed to the pathogenesis of some forms of HAPE. On the basis of such a likely contribution of inflammatory mechanisms, we induced pulmonary lung injury and inflammation by priming rats with Salmonella enteritidis endotoxin (ETX) (0.1 or 0.5 mg/kg body wt ip) and examined the influence of added exposure to simulated hypobaric hypoxia (24 h, 4,300 m). The animals that were primed with ETX and exposed to hypoxia, but not those that received either ETX or hypoxia alone, developed lung vascular damage. This vascular damage manifested itself histologically and by increases in the lung vascular permeability-surface area product and the lung bloodless wet weight-to-dry weight ratio. The bronchoalveolar lavage fluid of ETX-primed hypoxia-exposed rats contained a greater number of white blood cells and a higher concentration of protein compared with that of the ETX-primed rats. Hearts of ETX + hypoxia-treated rats showed an increased ratio of right ventricular weight divided by body weight (RV/BW). Neutropenia prevented the development of pulmonary edema and the increase in ETX + hypoxia rats with a Ca2+ entry blocker inhibited lung injury and RV hypertrophy, these results indicate that ETX priming causes pulmonary edema at high altitude and suggest a role for neutrophils and Ca2+ in this rat model of lung injury.

[Estimation of filtration variables in isolated rat lungs for evaluation of pulmonary microvascular permeability]

In order to evaluate the microvascular permeability of donor lungs, we calculated the filtration variables; K (reflection coefficient), simultaneously. For the calculation of filtration variables, the isolated rat lungs were kept in zone three conditions (pulmonary arterial pressure > pulmonary venous pressure > alveolar pressure). We used Krebs-Henseleit solution (K-H) with 6% bovine serum albumin for the perfusate, and maintained perfusion using a constant pressure circuit system. The pulmonary venous and alveolar pressures were maintained at 2.5 and 2.0 cmH2O, respectively, and pulmonary arterial pressure was set so that change in lung weight occurred. We increased both pulmonary arterial and venous pressures by 3 cmH2O simultaneously, and obtained the initial filtration rate. Then we diluted the perfusate with K-H to about half concentration, and obtained the initial filtration rate. We obtained values of filtration variables of K=4.55 mg.min-1.cm H2O-1.g-1], Ppmv=0.59 cmH2O, and sigma =0.617. These values agree with values from previous reports. Since these three filtration variables are interrelated, this method for simultaneous measurement is more accurate than independent measurements. The chief advantages of this method are that it does not require direct measurement of interstitial pressure or collection of lymph fluid, and all variables are obtained simultaneously. Using this method, the vascular permeability of isolated rat lungs, can be estimated.