Isolation and properties of type II alveolar cells from rat lung

Type II alveolar cells can be isolated and partially purified from adult rat lung by a series of steps that includes enzymatic digestion of the lung with trypsin and separation of cells on a discontinuous albumin density gradient. The yield of the isolated type II cells depends on the supplier and the housing of the rats used to prepare the cells. With specific pathogen-free rats housed in a laminar flow hood, the yield was 20.3 x 10(6) cells per rat, of which 50 per cent were type II cells. With rats from 2 other suppliers and no special housing, the yields were 8.8 and 8.3 x 10(6) cells per rat, of which 67 and 65 per cent were type II cells. The ultrastructural appearance of the isolated cells was similar to that of cells from intact lung, except for some dilatation of the endoplasmic reticulum and the perinuclear space. Most cells (92 +/- 5 per cent) excluded the vital dye, trypan blue. The cells consumed O2 at the rate of 76 +/- 12 nmole per 10(6) cells per hour and released only 5.7 +/- 2.0 per cent of their lactate dehydrogenase, a cytoplasmic enzyme, into the medium after 1 hour of incubation. The isolated type II cells contained disaturated phosphatidylcholine, a major component of purified surface-active material. The cells, however, had a low glucose utilization compared to their O2 consumption, which may indicate an abnormality in the metabolism of glucose. This population of cells could be further purified to 89 per cent type II cells by unit gravity velocity sedimentation.

Conversion of lamellar body membranes into tubular myelin in alveoli of fetal rat lungs

Fluid-filled lumina of fetal rat lungs contain lamellar bodies (LBs) as well as tubular myelin (TM), both of which are thought to be stores of phospholipid-rich pulmonary surfactant. The alveolar epithelium is believed to secrete LBs, but neither the origin nor the mechanism of TM formation is entirely certain. The main objective of this study was to determine the relationship between secreted LBs and TM and to define membrane phenomena which occur during TM formation. I examined lung tissues of 20-21 day-old fetuses (day 22 = term) using transmission and high voltage transmission electron microscopy and cytochemistry. My findings indicate that secreted LBs, identified by the presence of an acid-phosphatase reactive core, are the precursor of TM. Secreted LBs are highly organized structures which contain structurally specialized areas, one of which is a "mini-lattice" structure similar to TM. During TM formation, fuzzes or 8.0-nm diameter particles appear on transition membranes, although LB membranes appear to lack both structures. Similar particles are present on TM membranes and are generally associated with membrane intersections. My results provide evidence that TM is formed from LBs within the alveolar lumen by mechanisms which may be complex.

Shear-induced hemolysis with commercial and glow discharge silicones

The hemolytic characteristics of 14 different polydimethyl-siloxane materials were studied, using a rotating disk device to shear whole human blood for 6000 sec. Disk surfaces included commercial Silastic products with and without silica filler, coatings formed from hexa-methyl and tetra-methyl disiloxane monomer vapors by glow discharge, and heparinized silicones. Results are presented in the form of kinetic hemolysis curves (KHC)--plots of plasma hemoglobin vs. time--and analyzed in terms of the slopes of these curves in the 1500-6000 sec region where the KHC is nearly linear. It was found that most silicone products are low-hemolysis materials, comparable to polyethylene (PE) but often about 20% less ehmolytic; one product was superior by about 40%. The only consistent exceptions to this were the glow discharge surfaces from HEXA-methyl disiloxane (15-80% poorer than PE) and heparinized surfaces (70-280% more hemolytic than PE).

Inhibition of HeLa cell messenger RNA translation by 7-methylguanosine 5'-monophosphate

Translation of HeLa cell RNA containing poly(A) in a wheat germ cell-free system is markedly but incompletely inhibited by 7-methylguanosine 5'-monophosphate (m7G5'p). We have analyzed the translation products synthesized in the presence of different concentrations of m7G5'p and find that translation of all mRNAs is equally inhibited. To demonstrate the specificity of the inhibitor for RNAs with 5'-terminal m7G5' ppp... we show that specific translation products of satellite tobacco necrosis virus RNA, which does not have this 5' terminus, are synthesized in the presence of m7G5' p. Protein synthesis programmed by endogenous mRNA in a HeLa cell-free system is inhibited after a 10-min lag by m7G5' p. Other guanosine nucleotides without the 7-methyl group or with the phosphate in a different position are not inhibitor. We show that translation of all mRNAs is inhibited to a similar extent by m7G5'p in the HeLa cell-free system, by synthesizing 35S-labeled proteins in the presence of different inhibitory concentrations of this nucleotide and analyzing the translation products by electrophoresis and autoradiography. Translation of encephalomyocarditis virus RNA added to the HeLa cell-free system is not inhibited by m7"g5p; this viral RNA does not have this nucleotide at the 5' terminus. This indicates that m7G5'p specifically inhibits translation of mRNAs with the 5' terminus m7G5'ppp... and suggests that initiation of translation of picornavirus RNA may proceed via a mechanism different from that of cellular mRNAs.

Discoidal bilayer structure of nascent high density lipoproteins from perfused rat liver

Rat livers were perfused for 6 h without added plasma proteins using washed erythrocytes and buffer in a recirculating system. An inhibitor to the enzyme lecithin-cholesterol acyltransferase (5,5'-dithionitrobenzoic acid) was added in some experiments to prevent modification of substrate-lipids contained in secreted lipoproteins. The inhibitor did not detectably alter hepatic ultrastructure or gas exchange, but it inhibited the secreted lecithin-cholesterol acyltransferase by more than 85%. Very low density lipoproteins in perfusate were unaltered but the high density lipoproteins obtained from livers perfused with the inhibitor appeared disk-shaped in negative stain by electron microscopy with a mean edge thickness of 46 +/- 5 A and a mean diameter of 190 +/- 25 A. The high density lipoproteins were composed predominantly of polar lipids and protein with only small amounts of cholesteryl esters and triglycerides. The major apoprotein of these discoidal fractions had the same electrophoretic mobility as the arginine-rich apoprotein, whereas plasma high density lipoproteins contained mainly the A-I approtein. In all these respects the discoidal perfusate high density lipoproteins closely resemble those found in human plasma which is deficient in lecithin-cholesterol acyltransferase. Perfusate high density lipoproteins obtained in the absence of the enzyme inhibitor more closely resembled plasma high density lipoproteins in chemical composition (content of cholesteryl esters and apoproteins) and in electron microscopic appearance. Purified lecithin-cholesterol acyltransferase synthesized cholesteryl esters at a substantially faster rate from substrate lipids of perfusate high density lipoproteins than those from plasma. The discoidal high density lipoproteins were the best substrate for this reaction. Thin sections of plasma high density lipoproteins indicated a spherical particle whereas discoidal high density lipoproteins stained with the characteristic trilaminar image of membranes. These observations suggest that the liver secretes disk-shaped lipid bilayer particles which represent both the nascent form of high density lipoproteins and preferred substrate for lecithin-cholesterol acyltransferase.

Human urinary and liver conjugates of 17alpha-ethnylestradiol

Chromatographic profiles of the conjugates of 17alpha-ethynylestradiol (EE2) were obtained from the urine of castrate and normal women given tritium labeled EE2 orally. Five distinct radioactive peaks were observed, with considerable quantitative variation between individuals. Glucosiduronate fractions comprised the dominant excreted radioactivity. In vitro incubation of normal human liver also produced five conjugate types. Simultaneous intravenous/oral (14C/3H) administration of EE2 demonstrated conversion to identical urinary conjugate and free steroid products, with a greater excretion of the intravenous material. Authentic 3-glucuronide of EE2 was synthesized and its position in the chromatographic system relative to the urinary conjugate peaks demonstrated.

Shear-induced hemolysis: effects of blood chemistry (including aging in storage) and shearing surfaces

Rotating disks were used to hemolyze blood under low-stress laminar flow conditions. In the first sequence of tests, kinetic hemolysis curves (KHC) were obtained with polyethylene disks for three well-characterized bloods and repeated over a period of four weeks. Each blood had a KHC with different shape, which maintained its characteristics while aging. Correlations were sought between D6000 (percent of complete hemolysis, after 6000 sec of shear) and D0 (measured before shear) by two means of data analysis, in terms of blood chemistry. It was found that uric acid and very-low-density lipoprotein levels were most useful in predicting the characteristic D6000 vs. D0 relation for each blood, and that glucose levels correlated the rate of aging as measured by hemolysis. Other chemical factors are also displayed in terms of their influence on D0. The second series of tests consisted of comparing the KHC for four disk materials using a fourth blood, then repeating with a fifth blood. Hemolytic rankings of the materials were the same with these two blood, although the KHC shapes differed. The rankings were: polyvinyl chloride greater than Silastic approximately equal to polyethylene greater than polyether urethane, with PVC most hemolytic. In another sequence for examining materials effects, five different bloods were used to compare the hemolytic properties of Teflon, nylon, and polyethylene disks. Although the KHC for the three disks bore different relationships to each other with each different blood, extrapolation of data beyond 6000 sec suggests a ranking of Teflon greater than nylon greater than polyethylene.

Suppression of shear-induced hemolysis by three plasma proteins

Hemolysis was induced in erythrocyte suspensions by shearing between rotating metal disks 10 cm in diameter at 325 rev/min; stresses did not exceed 100 dynes/cm2. The role of proteins (gamma-globulin, G; albumin, A; fibrinogen, F) in the environment was tested in two ways. First, disks were precoated by exposure to protein solutions of physiologic concentration and then used to hemolyze the suspensions. Tests carried to 10(4) sec showed protective effects, relative to shearing with virgin disks, with a ranking G greater than A greater than F. Second, proteins were dissolved in the suspension media and hemolysis compared to the case without protein. Large suppression of hemolysis was found during storage (G approximately A greater than F) but only G offered significant protection against shear.

The permeability of muscle capillaries to horseradish peroxidase

The main objective of this study was to determine the pathways by which horseradish peroxidase (HRP) can cross the endothelium of muscle capillaries. Specimens of mouse diaphragm were fixed for cytochemical analysis at various intervals after intervenous injection of 0.5 mg HRP, at 4 min after intervenous injection of varied amounts of HRP, and at 4 min after intervenous injections in various volumes of isotonic NaCl. Our findings indicate that endothelial junctions serve as a barrier which may allow passage of very limited amounts of HRP. They also suggest that endothelial vesicles transfer HRP from the capillary lumen to the pericapillary interstitium as well as in the reverse direction. Increasing the volume of solution injected to approximately 30% of total blood volume did not increase the amount of HRP that left the capillary lumen. Our results with HRP do not provide clearcut evidence that endothelial junctions are the site of the small pore.

The urinary metabolites of 17alpha-ethynylestradiol-9alpha,11xi-3H in women. Chromatographic profiling and indentification of ethynyl and non-ethynyl compounds

Metabolites of 17alpha-ethynylestradiol (EE2) were obtained from human urine following ingestion of tritium-labeled EE2. Over 95% of the recovered activity was found as conjugated steroids and these were separated into four groups by chromatography of the urine extract on Sephadex LH-20 with chloroform-methanol (1/1) + 0.01M NaCl. The two major conjugate fractions appeared to be almost exclusively glucosiduronates. Enzymatic hydrolysis liberated at least ten different EE2 metabolites as shown by chromatography on Sephadex LH-20 with benzene-methanol (85/15). After additional separation and purification of these metabolites, positive identification was obtained for nine radioactive compounds by either gas liquid chromatography-mass spectrometry or reverse-isotope recrystallization. Five were ethynyl compounds: EE2, 2-MeO EE2, 16beta-OH EE2, 2-OH EE2 and 6alpha-OH EE2. The other four were de-ethynylated estrogens: estrone, estradiol-17beta, estriol, and 2-Me-O-estradiol-17beta.

A simple and inexpensive membrane "lung" for small organ perfusion

A disposable coil of thin-walled Silastic tubing, permeable to oxygen and carbon dioxide, functioned as a "lung" for perfusion of isolated rat liver. This "lung," which can be easily assembled from laboratory supplies, has a number of advantages over devices that utilize large air-liquid interfaces for gas exchange. Rates of hepatic lipoprotein triglyceride secretion, comparable to those obtained with more complex oxygenation systems, are achieved with this simple device.

Trials of aqueous killed influenza vaccine in Canada, 1968-69

The appearance of the pandemic A/Hong Kong/1/68 (H3N2) influenzavirus strain provided an opportunity for a clinical field trial of influenza vaccines in Canada during the winter of 1968-69. As by November 1968 there were reports of influenza B activity and as supplies of A2/HK/68 vaccines were limited, it was decided to make a series of strictly randomized double-blind trials comparing A2/HK/68 vaccines not only with B/Mass/66 vaccines but also with a bivalent vaccine that was already in production and contained B/Mass/66 and A2/Mtl/68, the latter a strain isolated in Canada during January 1968. In 4 trials, a total of 13 729 military personnel and 4 795 primary schoolchildren were vaccinated. Reported vaccine reactions were less than 0.1% with zonally-purified vaccines and 2.6% with the "standard" aqueous killed bivalent vaccine. Three children had serious reactions. Surveillance detected an outbreak of influenza in the first two trials on the military. The 3 vaccines containing A2 strains gave similar clinical protection conservatively estimated at 42-55% but probably about 80%. The effectiveness of the A2/Mtl/68 vaccine, which was in production before the Hong Kong variant had been isolated, was unexpected. In the absence of a vaccine specific to a new pandemic strain, it should not be assumed that a vaccine made from another recent strain could not be useful.

Urinary testosterone glucuronide as a measure of endogenous testosterone production

It is generally assumed that urinary excretion of testosterone glucuronide (TG) represents a relatively constant fraction (about 1 %) of the circulating testosterone which is metabolized. For this urinary TG to be a reliable indicator of testosterone production, the constancy of the fractional conversion of endogenous testosterone to urinary TG must be validated. Small changes in a low fractional conversion would induce large errors in the estimate of endogenous production. Following intravenous injection of [4-14C] testosterone, the per cent of the injected material found in the testosterone glucuronide fraction of a 48 hour urine collection was determined in several groups of subjects. In eight males the value ranged from 0.80 to 2.34%; in ten normal females from 0.26 to 0.84%; and in fifteen hirsute females from 0.05 to 0.80 %, a 16-fold difference. It is concluded that the assessment of endogenous testosterone production from urinary TG is materially influenced by changes in fractional conversion, and this introduces a very large degree of unreliability in the interpretation of urinary TG excretion data.