Permanent cell culture lines of rat erythroleukemia and growth inhibition by dexamethasone in vitro

Four erythroleukemia cell lines were established in vitro from rats with primary leukemias induced by a set of intravenous injections of 7,8,12-trimethylbenz[a] anthracene (TMBA). These cell lines were grown in Dulbecco's medium with 20% inactivated fetal calf serum; they were characterized by specific consistent chromosome abnormalities, related to No. 2 chromosome, which were maintained in culture for more than 1 year. Addition of dexamethasone prevented the cell growth of 2 of the cell lines in this medium but failed to alter the growth rate of the other 2 cell lines. These findings are correlated with karyotype abnormalities involving chromosome No. 2.

Age-related changes in cholesterol and bile-acid metabolism in spontaneously hypertensive rats

Age-related changes in serum and liver cholesterol, phospholipid and triglyceride levels, serum lipoproteins, biliary secretion of cholesterol, phospholipids and bile acids, fecal excretion of sterols and bile acids, and the pool size of bile acids were examined in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKR). SHR showed distinct age- and sex-related changes when young and marked aged-rat hypercholesterolemia after 1 yr of age. (1) Cholesterol shifted from blood to the liver between 10 and 20 wk only in male SHR and not at all in WKR. (2) Serum lipoprotein percentages changes; alpha-lipoprotein decreased, pre-beta-lipoprotein increased, but beta-lipoprotein did not change. These changes appeared only in male SHR and after 13 to 15 wk of age. (3) Liver enlargement in SHR, although not detected at 5 to 6 wk, progressed more rapidly than in WKR, giving values almost double those in WKR after 13 to 15 wk. Liver enlargement in female SHR was much less than in the male. (4) Bile flow, biliary secretion, and the pool size of bile acids increased. However, when expressed on the basis of liver weight, these values were similar to those in WKR, suggesting that the increases were caused by the hepatomegaly. (5) Differences appeared in the bile acid composition. A large amount of beta-muricholic acid was present in SHR of both sexes and the cholic acid percentage was low in male SHR. (6) Changes were observed in fecal bile acid excretion. Since the daily amounts in male SHR were similar to those in WKR, the hepatic synthesis activity (mg per day per 10 g liver) in male SHR was almost half that in WKR at all ages.

Convective cell structures revealed by Mie laser radar observations and image data processing

Mie scattering laser radar has been used to study the structure of the convective mixed layer in optically clear air. Two-dimensional image data obtained by scanning measurements (PPI and RHI modes) have been processed using edge-enhancement techniques to display distinct structures within the convective layer. The structures of convective cells penetrating into upper clean air were very similar to those obtained previously by sodar, radar, and FM-cw radar.

Endurance training regimen based upon arterial blood lactate: effects on anaerobic threshold

The purpose of this investigation was to assess the effect of endurance training based upon the intensity as determined by the arterial blood lactate concentration (LA). Seven healthy male college students performed endurance training on a Monark bicycle ergometer for 15 min on 3 days/week for 8 weeks, at an intensity corresponding to 4 mmol X l-1 arterial blood LA determined during an incremental exercise test (25 watts increment every minute on a bicycle at 50 rpm). Another six male students served as the control group. To assess the training effect, both an incremental exercise test and a submaximal exercise test were performed before and after the endurance training. In the incremental exercise test, VO2max, VE at VO2max, anaerobic threshold (AT), and the onset of respiratory compensation for metabolic acidosis (RCMA) were measured. AT was determined as the point at which arterial LA rose above the resting value, and RCMA was determined as the point at which Paco2 decreased during the incremental exercise test. After training, AT increased significantly (37% increment expressed in VO2, p less than 0.05). There was a significant increase (p less than 0.05) in RCMA (17%) and VO2max (14%). This training decreased VO2 (4%), VE (15%), heart rate (10%), respiratory exchange ratio (5%), and LA (23%) significantly (p less than 0.05) during the submaximal exercise test after training. On the other hand, there were no significant changes in the control group through the period when the training group performed their training. These results showed that the endurance training intensity corresponding to 4 mmol X l-1 arterial blood LA was effective for the improvement in AT as well as VO2max. It is suggested that the present training regimen could delay the onset of anaerobic glycolysis, thus shifting AT to the higher workload and decreasing LA at a given submaximal exercise after training.

[Antibacterial activities of cefotiam against various pathogens isolated from clinical materials (author's transl)]

Bacteriological evaluation was made on cefotiam (CTM), a new broad-spectrum cephalosporin antibiotic, and the following results wer obtained. 1) CTM has shown very potent antibacterial activities against Staphylococcus aureus, Escherichia coli, Edwardsiella tarda, Citrobacter intermedius, Salmonella, Klebsiella, Proteus mirabilis, Proteus rettgeri, Proteus inconstans, Yersinia enterocolitica, Aeromonas hydrophila, Plesiomonas shigelloides and Pseudomonas putrefaciens. 2) Streptococcus faecalis, Enterobacter and Proteus morganii isolated from urine, Serratia and glucose non fermentative Gram-negative bacilli except Pseudomonas putrefaciens, were almost insusceptible to cefotiam.

Effect of clinofibrate, a new hypolipidemic agent, on biliary and serum lipids in patients with hyperlipidemia

Clinofibrate was given to 15 patients with hyperlipidemia, for 6-8 weeks at the daily dose of 600 mg, and its effect on 3 biliary lipid components (cholesterol, bile acids and phospholipids) and on the lithogenic index was investigated. After clinofibrate treatment, 6 of the patients were given 1.5 g/day clofibrate for 6-8 weeks to compare the effect of clofibrate with that of clinofibrate. The molar percentages of biliary cholesterol and phospholipids to the total mol number of the 3 biliary lipid components decreased, and that of bile acids increased during clinofibrate administration. In this way, the molar ratio of bile acids to cholesterol increased during the treatment. Neither the lithogenic index calculated by the formula of Admirand and Small nor that of Hegardt, Dam and Holzbach was altered significantly by the treatment. There was no apparent relationship between the effect of the drug on the lithogenic index and any of the factors initial lithogenic index, rate of decrease of serum lipids, or type of hyperlipidemia. Although clofibrate had no significant effect on the maximum solubility of cholesterol in the bile, the molar percentage of biliary cholesterol was elevated and the lithogenic index increased as compared with the control and clinofibrate period. No significant influence on bile acid composition in the bile was observed, with either clinofibrate or clofibrate.

Primary ovarian lymphoma associated with Meigs' syndrome: a case report

A case is presented of primary undifferentiated lymphocytic lymphoma, non-Burkitt, of the right ovary associated with Meigs' syndrome. The diagnosis was based upon the findings of tumor imprint cytology, histopathology and electron microscopy. The ultrastructural observations were the most diagnostic, revealing well-developed, rough endoplasmic reticulum and dilated cisternae in the cytoplasm of the tumor cells. An association of Meigs' syndrome with a rare ovarian lymphoma has not been previously reported. The abnormal-appearing mesothelial cells in the pleural effusion were proven to be reactive and not malignant by comparison with the tumor cells demonstrated by imprint cytology of this ovarian lymphoma.

Effects of cholesterol-rich diet and hypolipidemic drug (clofibrate, CPIB) on the adrenal cortex in rats--ultrastructural stereological and biochemical analysis

Stereological analysis at the electron microscope level was performed on zona fasciculata and zona reticularis of the adrenal cortex of male rats maintained on normal rat chow, clofibrate (hypolipidemic drug), cholesterol-rich diet or cholesterol-rich diet plus clofibrate. The purpose of this study is to know whether the alteration in the serum cholesterol level is accompanied by an alteration in the ultrastructure and steroidogenic activity of the adrenal cortex, and to compare these changes with those of Leydig cells reported previously. The corticosterone level in both serum and the adrenal tissue of cholesterol-fed rats remained unchanged. Treatment of the cholesterol-fed rats with clofibrate caused a significant rise in the serum corticosterone level but the concentration in the adrenal remained unchanged. Lipid droplets increased in number and volume significantly in both cortical zones in all experimental groups as compared with the control group. But neither cholesterol feeding nor clofibrate treatment of normal rats caused a change in the volume or surface area of smooth endoplasmic reticulum (ER). Treatment with clofibrate on the cholesterol-fed rats resulted in a decrease in the volume of smooth ER in both cortical zones. Mitochondria showed no change except for a decrease in volume and inner membrane surface area of zona reticularis of cholesterol-fed rats. Peroxisomes did not proliferate but rather decreased in clofibrate-treated rats. These changes in the adrenal cortex were different from those in Leydig cells. Possible reasons for these differences were discussed.

The validity of anaerobic threshold determination by a Douglas bag method compared with arterial blood lactate concentration

Using an open circuit system (Douglas bag method), measurement of the anaerobic threshold (AT) was performed on ten healthy male college students during an incremental exercise test on a bicycle ergometer in an attempt to determine the validity of this method as compared with arterial blood lactate AT measurement. Blood samples were taken from either the radial or brachial artery through a Teflon catheter (3 ml/each time) every minute until the subject's maximal exercise tolerance was reached. Blood lactate was analyzed by the enzymatic method. Differences in work rate, VO2, %VO2max, VE, HR, and R at ATLA(AT determined by the increase in blood lactate) and at ATGE (gas exchange AT based on the non-linear increases in VE, VCO2, and other respiratory parameters), respectively, were all found to be statistically insignificant. There was a significant correlation (r = 0.866, p less than 0.01) between ATLA and ATGE when expressed i VO2 values (l/min). There was also a significant correlation between ATLA and VO2max (r = 0.778, p less than 0.01). These results indicate that the commonly used Douglas bag method could provide a valid non-invasive measure of anaerobic threshold.

Development of 132 Ir sources for brachytherapy

Techniques for the production of three kinds of 192Ir sources, i.e. hairpin, single-pin and seed, for brachytherapy were developed in Japan Atomic Energy Research Institute. Platinumiridium, alloy wire sheathed with platinum tube in advance were irradiated by the JRR-2 or JRR-3 reactor. The platinum tube cuts off beta-rays so as to minimize unnecessary radiation exposure to patients. Irradiation conditions were determined to obtain the radioactivity of 0.74 GBq (20 mCi) for a hairpin, 0.37 GBq (10 mCi) for a single-pin and 0.37 X 10(-1) GBq (1 mCi) for a seed, respectively, at the end of irradiation. Fluctuation in the linear distribution of the radioactivity along the hairpin source or the single-pin source was small enough on the viewpoint of its application. No significant impurity or surface contamination was observed in the source produced with pre-encapsulation. Seed targets were loaded in a polyethylene tube so as to be suitable for the new treatment technique of tumor. Irradiation of seed targets, packed alternately with nylon spacers in a polyethylene tube, was found to be satisfactory for preparing ribbon sources.

Effects of a cholesterol-rich-diet and a hypolipidemic drug (clofibrate, CPIB) on Leydig cells in rats stereological and biochemical analysis

Although the plasma testosterone level of the cholesterol-fed animals was almost the same as that of the control animals, the concentration in the tissue of the testis of the cholesterol group was 50% higher than that of the control group. Stereological data showed that the smooth endoplasmic reticulum of Leydig cells of the cholesterol group decreased by respectively 38 and 32% in volume as well as in surface area, and also mitochondria decreased by respectively 27 and 22% in volume as well as in surface area of inner membrane, as compared with the control group. Lipid droplets decreased remarkably in number and volume. Consequently Leydig cells of the cholesterol group diminished their cell volume to 83% of that of the control. When clofibrate was administered, the testosterone concentration in the testis tissue increased to 2.3 times that of the control group, although the plasma testosterone level was almost the same. In the Leydig cells of animals treated with cholesterol plus clofibrate peroxisomes decreased significantly and lipid droplets increased noticeably, as compared with the cholesterol-fed animals. These results might suggest that the testosterone production rate will decrease if the animals are fed for a longer period on a cholesterol-rich diet or immediately after the chow turns to a low-cholesterol-diet, and that the peroxisomes in the Leydig cells differ in their functional roles from those in the liver.

Cystosarcoma phyllodes of the breast with features of malignant fibrous histiocytoma

A case of a 33-year-old female with metastasizing malignant cystosarcoma phyllodes of the left breast showing histologic features of malignant fibrous histiocytoma is reported. Metastases consisting of only undifferentiated mesenchymal cells were found in the lungs, liver, pleurae, kidneys, ileum, and vertebrae. Seven cases of fibrohistiocytic tumors of the breast previously recorded in the literature were reviewed. Although rare, this type of tumor should be included in the differential diagnosis of mesenchymal mammary tumors.

Effects of cholic acid, chenodeoxycholic acid, and their related bile acids on cholesterol, phospholipid, and bile acid levels in serum, liver, bile, and feces of rats

Effects of sodium cholate, deoxycholate, chenodeoxycholate, and lithocholate on serum and liver cholesterol levels, bile flow, biliary cholesterol, phospholipids, and bile acids, and fecal sterols and bile acids were examined in Wistar strain male rats fed either an ordinary diet or a 2% cholesterol diet. Cholate and deoxycholate increased serum and liver cholesterol levels, serum pre beta-lipoprotein, bile flow, and biliary secretion of cholesterol, phospholipids, and bile acids, but chenodeoxycholate and lithocholate did not. The total amounts of sterols and of bile acids in the feces did not differ between the cholate and the chenodeoxycholate groups. All the bile acids except lithocholate decreased fecal coprostanol when the diet included cholesterol. Cholate and deoxycholate produced similar bile acid compositions in the bile and feces, as was the case between chenodeoxycholate and lithocholate, though chenodeoxycholate slightly increased the amount of muricholic acids, and lithocholate that of hyodeoxycholic acid, in the feces. The effects of cholate and deoxycholate are similar to each other but different from that of chenodeoxycholate or lithocholate in rats. Cholate causes marked accumulation of cholesterol in tissues, increased bile flow and biliary lipid secretion but chenodeoxycholate does not. Cholate is absorbed much more efficiently than chenodeoxycholate.

Geometrical form factor in the laser radar equation: an experimental determination

This paper describes a practical method for determination of the geometrical form factor in the laser radar equation. Based on the laser radar equation and the statistical homogeneity in the spatial aerosol distribution, the factor can be calculated from the field observations by laser radar. Some examples of correction by this factor are also presented.

Altered bile acid metabolism in alloxan diabetic rats

Changes of cholesterol, phospholipid, triglyceride or bile acid levels in serum liver, bile and feces after the treatment with alloxan were examined in Wistar strain male rats. Serum cholesterol, phospholipid and triglyceride levels and liver cholesterol level markedly increased but liver phospholipid and triglyceride levels remained unchanged. The lipid levels in serum very low density and low density lipoproteins were elevated but those in high density lipoprotein were not. Bile flow was not changed but biliary secretion of cholesterol, phospholipid and bile acids markedly increased. Among the biliary bile acid components, cholic acid markedly increased but the amount of chenodeoxycholic acid was similar to that of normal rats. Fecal excretion of deoxycholic acid increased but that of lithocholic and hyodeoxycholic acids decreased, and alpha, beta- and omega-muricholic acids did not change, thus, the total amount of fecal bile acids remained unchanged. Hepatic cholesterol synthesis was markedly depressed, while cholesterol 7 alpha-hydroxylase activity did not change and cytochrome P-450 content was elevated by about 40%. From such evidence, it was apparent that synthesis of cholic acid increased while that of chenodeoxycholic acid decreased and the total amount of bile acids synthesized did not change in the diabetic rats. Furthermore, marked increase of the pool size of cholic acid and hepatic secretion of cholic acid stimulated the absorption of lipids and produced a hyperlipidemia in the diabetic rats.

Detectivity estimation of the DAS lidar for NO(2)

The detectivity of an NO(2) spatial distribution by a DAS lidar was estimated under practical conditions, and its capability was clarified.

Cholesterol from serum and cholesterol-phospholipid dispersions by isolated rat hepatocytes in vitro

The rate of uptake of cholesterol by isolated rat hepatocytes from incubation medium containing rat serum was low and did not increase by the prolongation of incubation time up to 2 hr at 4 degree. However, the hepatocytes took up cholesterol very actively at 37.5 degree from serum as well as from a cholesterol-phospholipid dispersion. The cholesterol uptake by the cells from liposomes increased linearly with the increase of the cholesterol concentration of liposomes, but that from serum reached the maximum at about 1.5 mu mol/ml cholesterol and remained at a plateau level at higher concentrations. Cholesterol was transfered from every class of serum lipoprotein, although the uptake ratio was the highest from the LDL fraction. As the lipoprotein concentration was increased, the uptake ratio decreased in the same way as that observed in the incubation with whole serum. The concentration of labeled ester cholesterol in the medium decreased more rapidly than free cholesterol during incubation. Cholesterol in the hepatocytes, however, was found mainly as the free form, suggesting that ester cholesterol taken up by the cells was rapidly hydrolyzed. Cholesterol accumulation was not observed in hepatocytes incubated in medium containing serum, but their cholesterol content was increased after the incubation in medium with liposomes of high cholesterol concentration. Therefore the uptake of cholesterol by hepatocytes from serum lipoproteins is probably carried out by a process different from that of uptake from liposomes which is considered to be a physicochemical phenomenon.

Age-related changes in cholesterol and bile acid metabolism in rats

Age-related changes in serum and liver cholesterol, phospholipid and triglyceride levels, serum lipoproteins, biliary secretion of cholesterol, phospholipid and bile acids, and fecal excretion of sterols and bile acids were examined in Sprague-Dawley and Wistar strain male rats, 7 to 106 weeks in age. Serum and liver lipid levels increased with age in both strains but the liver phospholipid level remained unchanged. The proportion of serum alpha-lipoprotein increases and that of beta- and prebeta-lipoproteins slightly decreased. Cholesterol and phospholipids in low density lipoprotein and cholesterol in high density lipoprotein fractions also increased with age. Bile flow and biliary secretion of cholesterol and bile acids decreased in aged rats, but when they were expressed in terms of units per rat they were almost constant without regard to age. Pool size, synthesis, secretion, and turnover frequency of bile acids also did not change when they were expressed per rat, though 7-week-old rats showed a low value for turnover frequency. Biliary secretion of phospholipid, however, increased in aged rats. Biliary secretion of chenodeoxycholic and alpha-muricholic acids decreased but that of cholic and hyodeoxycholic acids increased. Daily excretion of feces and fecal neutral sterols decreases in aged rats but the excretion of bile acids remained constant regardless of age. The ratio of coprostanol and cholesterol in the total sterols was not affected. Fecal lithocholic, beta-muricholic and P10 (probably omega-muricholic) acids were decreased with age but the other bile acid components were not changed or were slightly increased.

Structure of extracellular polysaccharides of Escherichia coli strains 36M, 72M, and 29M isolated from coligranuloma of chick intestine. I. Polysaccharide from E. coli 36M

An extracellular polysaccharide was isolated from culture broth of Escherichia coli 36M, and fractionated on a column of Sephadex G-150 into two fractions; the high molecular weight portion (85% of the total polysaccharide) contained pyruvic acid, and showed a positive immune reaction with anti-Ps-I-serum obtained from a rabbit. The low molecular weight portion (15% of the total polysaccharide) showed a negative immune reaction. The methylation, Smith's degradation, partial acid hydrolysis and methanolysis of the higher molecular weight polysaccharide revealed a repeating structure as follows: (see article).

Feed-back control of cholesterol synthesis in partially hepatectomized rats

Partial hepatectomy caused a marked stimulation of cholesterol and fatty acid syntheses without affecting serum total cholesterol, total phospholipid and triacylglycerol concentrations of rats so far examined 48 h after the operation. Serum free cholesterol level, however, was increased by the treatment and the ratio of lysophosphatidylcholine to phosphatidylcholine was concomitantly decreased, suggesting the impairment of serum lecithin: cholesterol acyltransferase activity. The lipid content in the liver, especially triacylglycerol and ester cholesterol, was increased markedly by the operation. Feeding of a high cholesterol diet which elevated serum cholesterol and phospholipid levels to the partially hepatectomized rats, accelerated the accumulation of hepatic triacylglycerol and ester cholesterol by the partial hepatectomy. The weight of the regenerating liver was not influenced by cholesterol feeding, which suggested that cholesterol feeding did not inhibit the regeneration mechanism of the liver. The increase of cholesterol synthesis after partial hepatectomy was inhibited by cholesterol feeding. Therefore, it is conceivable that the negative feed-back control of cholesterol synthesis is induced by cholesterol feeding under the stimulated cell divisions of the liver after partial hepatectomy. It is suggested from the present data that a large amount of the cholesterol which is necessary for cell growth can be taken up from serum, when serum cholesterol concentration is high.

Effects of synthetic progestational steroids on liver and serum lipids in rats

Effects of norethisterone (NT) purified norethisterone (pure NT), norethynodrel (NE), medroxyprogesterone acetate (MAP), chlormadinone acetate (CMA) and desoxycorticosterone acetate (DOCA) on serum and liver lipid levels and serum lipoproteins were examined in both intact and estradiol-treated male rats. NT and NE caused a decrease in serum cholesterol and phospholipid levels, an increase in liver cholesterol level, no significant change in triglyceride levels of both serum and liver, with a significant change in serum lipoprotein patterns; a decreased in alpha- and beta-lipoproteins and a marked increase in pre beta-lipoprotein. Pure NT decreased serum cholesterol without causing any change in lipoprotein pattern. MAP, CMA and DOCA causee almost no effect on lipid levels in serum and liver, but CMA and DOCA increased alpha-lipoprotein and decreased beta- and pre beta-lipoproteins. An acute treatment with estradiol caused a decrease in alpha- and beta-lipoproteins and an increase in pre beta-lipoprotein with a decrease in serum lipid levels and an increase in liver lipids. By contrary, a chronic treatment with a marked hypercholesterolemia. This increase of alpha-lipoprotein in estradiol-treated rats was prevented by NT and NE, not affected or rather decreased by MAP but further increased with CMA and DOCA. These data suggest that the effects of synthetic progestational steroids on lipids are classified into two groups, 19-nortestosterone derivatives and 17alpha-hydroxyprogesterone derivatives including DOCA. The former caused a decrease in serum lipid levels with an increase of pre beta-lipoprotein and adecrease of alpha-lipoprotein. The latter caused almost no change or a slight increase in serum lipid levels with a decrease in pre beta-lipoprotein and an increase in alpha-lipoprotein, though it was not found in MAP.

Cholestero metabolism in rats sensitive to high cholesterol diet

There was great individual variation in the elevations of serum cholesterol concentrations in a Wistar strain of rats by the ingestion of a large amount of cholesterol, although their cholesterol concentrations were almost identical while under the feeding of a regular stock diet. Their serum total phospholipid and dextran precipitable beta-lipoproteins showed the same tendencies, but serum triglycerids concentration was not affected by the dietary supplement in both groups. So, the rats with the different elevation rates of serum cholesterol concentrations were divided into good, normo and poor responding groups to cholesterol ingestion by the degrees of the elvations and bred for several generations. Serum lipid levels in the descendants from hyperresponding rats were not different from those from hyporesponding rats during the observed period, when they were given a stock diet. However, the response of serum cholesterol level to oral cholesterol ingestion in the former was larger than that in the latter. Therefore, it is suggested that the susceptibility of serum cholesterol to cholesterol ingestion may be heritable from parents to their offsprings. By the results of the tracer experiments, it was demonstrated that neither hepatic cholesterol synthesis nor absorption was affected in hyperresponding rats. On the other hand, a half life of labeled cholesterol was prolonged in this selected group. The relative fractional turnover rate was 17.8 per cent in hyporesponding rats and 15.8 per cent in hyperresponding rats. Excretion of the radioactivity from labeled cholesterol into the bile in good responding rats with bile fistula was slower than that in poor responding rats. When 1 g per 100 g body weight of glucose was given to the rats after 40 hours fasting, hepatic cholesterol synthesis increased at the same rate in both groups of rats, but the induction of hepatic cholesterol 7alpha-hydroxylation in hyperresponding groups was slower than that in hyporesponding groups. The distribution rates of the radioactivities into livers seemed to be delayed in good responders after the labeled cholesterol was ingested orally.It means that some disturbances in cholesterol transport may exist which induce the metabolic abnormality in such animals. It was shown that cholesterol metabolism was impaired in aged animals as compared with young ones. Serum cholesterol concentrations were elevated in good responders more than in poor responders by aging. The inborn errors of cholesterol metabolism in such animals might be emphasized from the fact of the impairment of cholesterol metabolism by the aging process.

Lung damage caused by phospholipase C and the changes in phospholipids in the rat lung

The lipid and protein fractions of the endobronchial lavage fluid from the normal rats which contained the lung surfactant were analysed. Lecithin, the main main component of the lung surfactant, was exclusively combined with a dextran precipitable protein. This protein then behaved as beta-globulin on cellulose acetate electrophoresis or low density lipoprotein on agarose gel filtration. After administration of phospholipase C (from Clostridium Welchii), the protein content of the lavage fluid increased markedly. The amount of dextran precipitable protein also increased markedly and its properties remained the same on gel filtration after treatment with phospholipase C. The phospholipids in the lavage fluid were not affected, although the total phospholipids in the lung tissue, especially lecithin, did decrease during the 10 days after treatment. Histopathologically, an eosinophilic dense exudative fluid appeared in both the interstitium and the broncho-alveolar spaces. A large number of the alveolar lining cells disappeared and a few of them were desquamated into the alveolar spaces. Thus, the immediate destruction of the alveolar lining cells after the administration of phospholipase C resulted in interstitial pneumonia in 10 days. The significance of phospholipase in pulmonary inflammation is discussed.