Comments on the history of the Biological Stain Commission, Inc

Nearly 89 years ago, the Society of American Bacteriologists appointed Dr. Harold Conn to form a committee to standardize the stains and dyes used in biological and medical research and diagnosis. Dr. Conn's efforts led to formation of the Committee on the Standardization of Biological Stains, later incorporated as the Biological Stain Commission. This article traces some of the events and factors that shaped the course of the Biological Stain Commission into its current form and functions. Its principal function is to ensure that the biological and medical communities have access to high quality, dependable and consistent biological dyes and stains.

Revised procedures for the certification of carmine (C.I. 75470, Natural red 4) as a biological stain

Carmine is one of the original dyes certified by the Biological Stain Commission (BSC). Until now it has lacked both an assay procedure for dye content and a means to positively identify the dye. The methods for testing carmine in the laboratory of the BSC have been revised to include spectrophotometric examination at pH 12.5-12.6 to determine that the dye is carmine (lambda(max)=530-335 nm). The maximum absorbance of a solution containing 100 mg of dye per liter of water, adjusted to pH 12.5-12.6, which provides a relative measure of dye content, should lie in the range 1.2 to 1.8. If the dye is not carmine, spectrophotometry at pH 1.9-2.1 shows whether it is carminic acid (lambda(max)=490-500 nm) or 4-aminocarminic acid (lambda(max)=525-530 nm). The latter two dyes, which are also called carmine when sold as food colorants, have physical properties different from those of true carmine. The functional tests for carmine as a biological stain are Orth's lithium-carmine method for nuclei, Southgate's mucicarmine method for mucus, and Best's carmine method for glycogen.

Stain and dye stability over a 30-year period: a comparison of certified dye powders by the Biological Stain Commission

The Biological Stain Commission (BSC) Assay Laboratory has received numerous inquiries during the past several years regarding the long-term stability of stain and dye powders, particularly since packaging requirements call for expiration dates on reagents. We have conducted a study to examine the long-term stability of selected dye powders. We used the standard procedures of the BSC for testing biological stains for certification to give an indication of the long-term chemical stability as well as staining performance of the dye powders. An earlier study by Emmel and Stotz examined the stability of various dye powders after a five-year storage period. The present study is a follow-up project covering the same dyes after storage for 30 years. The dye samples chosen for the study are the same samples used in the five-year storage period study and give comparative results for all three time periods. The results of this study affirm the generally held speculation that dye powders are stable for many years and thus have a substantial shelf-life.

A brief history of the Biological Stain Commission: its founders, its mission and the first 75 years

The need for batch-to-batch consistency in available dyes and stains used for biological purposes posed a considerable problem for United States scientists following World War I. Prior to that time, most of the acceptable stains in this country were of German origin. In an attempt to standardize the performance of biological stains and dyes, the Society of American Bacteriologists in 1922 appointed Dr. Harold Conn to form the Committee on the Standardization of Biological Stains. To assist him, Dr. Conn recruited scientists from several major professional scientific societies. Mr. Rolland Will, a Rochester, NY, vendor of stains, was also instrumental in the Committee's success. This article traces the origin, mission and accomplishments of the product of that Committee, the Biological Stain Commission, through the past 75 years, and focuses on some of the major events that influenced and shaped its development.

Ultrasound enhancement of rabbit femoral artery thrombolysis

Experiments were conducted to evaluate the potential of low-intensity, externally applied ultrasound to accelerate arterial thrombolysis in an animal model and to characterize potential effects of ultrasound exposure on vessel wall morphology. The femoral arteries of 32 rabbits were exposed, a flowprobe was positioned around the vessel, and a stenosis produced with two circumferential silk sutures to reduce flow by 50%. Thrombosis was achieved by injecting thrombin through the cannulated superficial epigastric branch into a 1-cm segment of femoral artery which was isolated for 20 min. Streptokinase was administered intravenously as a 15,000 U/kg bolus followed by an infusion of 15,000 U/kg per h. Ultrasound (1 MHz, 2 W/cm2) was delivered to the thrombosed vessel during streptokinase administration in 17 animals, and 15 control animals received sham ultrasound only. Thrombolysis occurred in nine of 17 (53%) animals receiving both streptokinase and ultrasound, and this was significantly greater than the rate in animals receiving streptokinase alone (2/15, 13%; P=0.025). Ultrasound caused a mean temperature elevation of 4 degrees C in exposed tissues. Light and electron microscopy demonstrated increased platelet accumulation on thrombi in ultrasound-treated vessels compared with controls. Endothelial cell vacuolation was seen by electron microscopy in ultrasound-exposed vessels. The results indicate that externally applied, low-intensity ultrasound can significantly enhance thrombolysis in a rabbit arterial model. Possible adverse effects are minor and include platelet accumulation, temperature elevation and minor endothelial changes. Externally applied ultrasound has potential value as an adjunct to thrombolytic therapy.

Thresholds for fetal hemorrhages produced by a piezoelectric lithotripter

Hemorrhage to fetal tissues occurred when late-term pregnant mice were exposed to lithotripter fields of relatively low amplitude. These hemorrhages were always observed in tissues near developing bone or cartilaginous structures such as the head, limbs and ribs, while soft tissues distant from bone were relatively free of hemorrhage. Thresholds for hemorrhage in the fetus were determined for exposures of pregnant mice on the 18th day of gestation to 200 pulses from a piezoelectric lithotripter. Animals were exposed to axial peak positive pressures of either 0 (sham), 1, 2, 3, 5 or 10 MPa. Thresholds for hemorrhage to the head, limbs, ribs and lung were all < 1 MPa.

Age dependence of ultrasonically induced lung hemorrhage in mice

Thresholds for ultrasonically induced lung hemorrhage were determined in neonatal mice (24-36 h old), juvenile mice (14 d old) and adult mice (8-10 weeks old) to assess whether or not the threshold for lung hemorrhage is dependent upon age. Ultrasonic exposures were at 1.15 MHz with a pulse length of 10 microseconds, pulse repetition frequency of 100 Hz and a total exposure duration of 3 min. The threshold for lung hemorrhage occurred at a peak positive acoustic pressure of approximately 1 MPa for mice in all three age groups. Although the thresholds were similar for neonatal, juvenile and adult mice, the sizes of the suprathreshold hemorrhages were significantly larger in adult mice than in neonatal or juvenile mice.

Remnants of Albunex nucleate acoustic cavitation

Mice were injected with 0.1 mL Albunex and exposed to 200 pulses from a piezoelectric lithotripter at times ranging from 5 min to 24 h following injection. Each pulse was approximately 1.5 sinusoidal oscillations at a fundamental frequency of approximately 0.1 MHz with pressure amplitude of approximately 2 MPa. Although the contrast agent ceases to be an effective scatterer of diagnostic ultrasound after a few minutes in the circulation, the modest lithotripter exposures caused significant hemorrhaging in bladder, mesentery and intestine for periods of up to 4 h after injection. The results demonstrate either that highly stable bubbles much smaller than resonance size or air-containing fragments of the shells of Albunex serve as effective nuclei for acoustic cavitation.

The influence of contrast agents on hemorrhage produced by lithotripter fields

Ultrasonic contrast agents greatly increase the side effects of low-amplitude lithotripter fields in mice. Using a piezoelectric lithotripter, adult mice were exposed to 200 lithotripter pulses with a peak positive pressure amplitude of 2 MPa. During the exposure period, mice were injected with approximately 0.1 mL of the ultrasonic contrast agent Albunex. For comparison, another group of mice experienced the same lithotripter exposures, but were not injected with contrast agent. Following exposures, animals were sacrificed and observed for hemorrhage in various organs and tissues. Mice exposed to the lithotripter field alone had minimal hemorrhage only in the intestine and lung. In comparison, mice injected with Albunex during exposure exhibited extensive hemorrhage in the intestine, kidney, muscle, mesentery, stomach, bladder, seminal vesicle and fat.

Bioeffects of positive and negative acoustic pressures in vivo

In water, the inertial collapse of a bubble is more violent after expansion by a negative acoustic pressure pulse than when directly compressed by a positive pulse of equal amplitude and duration. In tissues, gas bodies may be limited in their ability to expand and, therefore, the relatively strong effectiveness of negative pressure excursions may be tempered. To determine the relative effectiveness of positive and negative pressure pulses in vivo, the mortality rate of Drosophila larvae was determined as a function of exposure to microsecond length, nearly unipolar, positive and negative pressure pulses. Air-filled tracheae in the larvae serve as biological models of small, constrained bubbles. Death from exposure to ultrasound has previously been correlated with the presence of air in the respiratory system. The degree of hemorrhage in murine lung was also compared using positive and negative pulses. The high sensitivity of lung to exposure to ultrasound also depends on its gas content. The mammalian lung is much more complex than the respiratory system of insect larvae and, at the present time, it is not clear that acoustic cavitation is the physical mechanism for hemorrhage. A spark from an electrohydraulic lithotripter was used to produce a spherically diverging positive pulse. An isolated negative pulse was generated by reflection of the lithotripter pulse from a pressure release interface. Pulse amplitudes ranging from 1 to 5 MPa were obtained by changing the proximity of the source to the biological target. For both biological effects, the positive pulse was found to be at least as damaging as the negative pulse at comparable temporal peak pressure levels. These observations may be relevant to an evaluation of the mechanical index (MI) as an exposure parameter for tissues including lung since MI currently is defined in terms of the magnitude of the negative pressure in the ultrasound field.

Interleukin 3 enhances cytotoxic T lymphocyte development and class I major histocompatibility complex "re-presentation" of exogenous antigen by tumor-infiltrating antigen-presenting cells

We show that interleukin 3 (IL-3) enhances the generation of tumor-specific cytotoxic T lymphocytes (CTLs) through the stimulation of host antigen-presenting cells (APCs). The BALB/c (H-2d) spontaneous lung carcinoma line 1 was modified by gene transfection to express ovalbumin as a nominal "tumor antigen" and to secrete IL-3, a cytokine enhancing myeloid development. IL-3-transfected tumor cells are less tumorigenic than the parental cell line, and tumor-infiltrating lymphocytes isolated from these tumors contain increased numbers of tumor-specific CTLs. By using B3Z86/90.14 (B3Z), a unique T-cell hybridoma system restricted to ovalbumin/H-2b and implanting the tumors in (BALB/c x C57BL/6)F1 (H-2d/b) mice, we demonstrate that the IL-3-transfected tumors contain an increased number of a rare population of host cells that can process and "re-present" tumor antigen to CTLs. Electron microscopy allowed direct visualization of these host APCs, and these studies, along with surface marker phenotyping, indicate that these APCs are macrophage-like. The identification of these cells and their enhancement by IL-3 offers a new opportunity for tumor immunotherapy.

Thresholds for ultrasonically induced lung hemorrhage in neonatal swine

The threshold for generation of lung hemorrhage in adult mice by pulsed ultrasound has been shown to be approximately 1 MPa at the surface of the lung (10-microseconds pulse and a carrier frequency of 2 MHz). This investigation used neonatal swine to determine if the findings for mice can be generalized to other species. After exploratory observations, the inverse sampling method was used in a primary study (22 animals, 88 exposure sites) to determine the threshold for lung hemorrhage in neonatal swine. The primary study was followed by a separate confirmation study (13 animals, 48 exposure sites), testing the conclusions of the first study and comparing damage at subthreshold levels with sham-exposed animals. A separate investigation explored the histological nature of tissue damage at suprathreshold levels. A 2.3-MHz focused transducer (10 microseconds at 100-Hz pulse-repetition frequency) was incremented vertically for a distance of 2 cm over the chest of the subject for a total exposure period of 16 min. Animals were euthanized and lungs were scored by visual inspection for numbers and areas of gross hemorrhages. The threshold level for hemorrhage was approximately 1.5 MPa peak positive pressure in water at the surface of the animal or, at the surface of the lung, 1.1 MPa peak positive pressure, 1 MPa fundamental pressure, 0.9 MPa maximum negative pressure, 25 W cm-2 pulse average intensity or a mechanical index of 0.6. These values are essentially the same as those reported for adult mice.

In vitro radiation sensitivity of mouse lung fibroblasts isolated by flow cytometry

PURPOSE

Recently, we have isolated two major fibroblast cells (Thy-1+, Thy-1-) from mouse LAF1 lung tissue using the anti-Thy-1 antibody expression and fluorescence activated cell sorter. To examine the possibility that x- or gamma-ray-induced pulmonary fibrosis at the late stage of injury could arise from radioresistant cell subpopulations, the radiation sensitivities of Thy-1+ and Thy-1- cells were evaluated by the colony forming assay.

METHODS AND MATERIALS

Cell survival curves, repair of potentially lethal damage (PLD) and sublethal damage (SLD), and cell-age response curves were obtained after Cs-137 gamma-ray irradiation.

RESULTS

The cell survival curves measured after 0-10 Gy gamma-ray showed that Thy-1+ cells were slightly more radioresistant than Thy-1- cells. The D0, n, alpha, and beta values measured from the survival curves also confirmed this observation. After a single dose of 10 Gy, a small amount of PLD repair was observed in Thy-1- cells, while no PLD repair was found in Thy-1+ cells. Although the initial cell survival level of Thy-1- cells was lower, the final survival levels of Thy-1+ and Thy-1- cells became identical at 8 h after irradiation due to the PLD repair. After split-dose irradiation of 4 Gy followed by 4 Gy, a similar extent and rate of SLD repair was found in Thy-1+ and Thy-1- cells. Cell-age response curves were obtained from irradiated G0/G1, S, and G2M cells separated by centrifugal elutriation and irradiated with 8 Gy gamma-ray. The results indicated that Thy-1+ and Thy-1- cells had a similar S resistant, and G1, G2M-sensitive radiation cell-age response curve.

CONCLUSIONS

This study suggests that the selection of radioresistant lung fibroblast may not be responsible for the development of lung fibrosis in irradiated LAF1 mouse.

Acceleration of fibrinolysis by ultrasound in a rabbit ear model of small vessel injury

High frequency ultrasound has been previously shown to accelerate fibrinolysis in vitro at intensities that are potentially applicable for noninvasive administration clinically. To extend these findings in vivo, we have investigated the effects of ultrasound on fibrinolysis induced by streptokinase in a rabbit model of small vessel injury. Full thickness puncture wounds were made in rabbit ears with a scalpel blade. The rabbits were rested for 2-3 hours after cessation of bleeding to allow maturation of hemostatic plugs. Saline or streptokinase was then infused intravenously, and ultrasound was applied to some lesions at 1 MHz with a 50% duty cycle at 1 W/cm2 net intensity. Ear lesions in rabbits treated with saline showed no bleeding after 30 minutes whether they were exposed to ultrasound or not. Streptokinase alone induced bleeding after 19.7 +/- 5.5 minutes. Application of ultrasound significantly reduced the time to bleeding in streptokinase treated rabbits to 7.5 +/- 3.9 minutes (p < .002). The times to bleeding with "sham" ultrasound (18.8 +/- 5.6 minutes) and heating of the ear (18.0 +/- 5.6 minutes) during streptokinase administration were not significantly different compared to streptokinase alone. Histologic examination revealed that application of ultrasound resulted in a mild increase in interstitial edema and accumulation of polymorphonuclear leukocytes but did not cause vascular or other tissue damage. We conclude that the noninvasive, percutaneous application of ultrasound significantly accelerated streptokinase-induced fibrinolysis in this rabbit model of small vessel injury.

Morphological correlates of fractionated radiation of the mouse lung: early and late effects

PURPOSE

The definition and quantitation of radiation-induced morphologic alterations in murine lungs is presented.

METHODS AND MATERIALS

The extent of injury to the lung, which is the dose-limiting organ in the thorax, may be reduced by fractionating the total radiation exposure to permit partial repair of radiation-induced damage between fraction administration and also to permit a larger total exposure to be administered. We previously reported that, following fractionated radiation exposures, as the dose/fraction decreases, the total dose to reach an isoeffect increases, with an alpha/beta ratio of 3.2 and 3.0 for breathing rates and lethality, respectively. In the present report, we provide comparative morphologic evaluation of the effects of weekly fractionated (three doses at one dose/week), daily fractionated (15 doses at 1/diem), and hyperfractionated (30 doses at 2/diem) radiation exposures. The doses administered within each group were uniform. To determine morphologic alterations, LAF1 mice were irradiated with 3, 15, and 30 fractions delivered in 19 days overall treatment time. In the hyperfractionation schedule, the two fractions per day were separated by a 6-h time interval. Total doses were as follows: 15-21 Gy for weekly fractionation, 30-41.5 Gy for daily fractionation, and 30-49.5 Gy for hyperfractionated schedules. Lung tissue, recovered either 24 or 72 weeks following the final exposure, was evaluated by transmission and scanning electron microscopy and light microscopy.

RESULTS

Using a series of morphologic parameters, a total dose of 15 Gy in the weekly treatment schedule was found to be equivalent to a total dose of 30 Gy in the daily fractionation schedule and 37 Gy in the hyperfractionated treatment regimen at 24 weeks postirradiation. Measured at 72 weeks postirradiation, total exposures of 15 Gy on the weekly fractionation regimen corresponded to total exposures of approximately 30 Gy in both the daily fractionated and hyperfractionated regimens. Morphological damage was not uniform throughout the exposed lung and tended to be concentrated in lobes or portions of lobes.

CONCLUSIONS

In the three fractionation regimens studied, there is progressive sparing of the lung with increased fractionation (i.e., weekly < daily < twice daily) during the pneumonitic stage (24 weeks postirradiation). Both daily and twice daily fractionations provide increased sparing over weekly fractionation during the fibrotic stages (72 weeks postirradiation), but were not markedly different from each other (i.e., weekly < daily = twice daily).

Pulmonary changes induced by combined mouse beta-interferon (rMuIFN-beta) and irradiation in normal mice--toxic versus protective effects

This study in normal mice was undertaken to investigate possible enhancement of pulmonary toxicity by interferon-beta (IFN-beta) combined with single doses of irradiation. A pharmacokinetic study preceded the toxicity study to determine the optimal route and timing of IFN administration. Graded single doses of radiation were combined with graded doses of IFN. Pulmonary toxicity was determined using endpoints of alveolar surfactant and procollagen in lung lavage fluid at 7 days, breathing frequency, lethality and histology. Increased lethality was seen when IFN was combined with irradiation at 12.5 Gy vs. irradiation alone. This occurred between 20 and 30 weeks post treatment with no increased breathing frequency or surfactant release, suggesting independent mechanisms of injury. Increased breathing frequency after 40 weeks, usually associated with fibrosis, was less pronounced for IFN treated vs. irradiation only controls. Ultrastructural studies at 72 weeks suggest reduced fibrosis in lungs of IFN treated vs. irradiation only controls. Supporting this was the finding that Procollagen III, a biosynthetic precursor of collagen, was increased in the lavage fluid at 7 days for all radiation doses but decreased with the addition of IFN at 12.5 and 15 Gy. Interferons can act either as sensitizers or radioprotectors, depending on the biological system and type of interferon. Our study suggests that while IFN-beta may increase the acute effects of radiation in the mouse lung, some protection from radiation-induced fibrosis, possibly related to alteration of immune mechanisms, may exist.

Morphological effects of pulsed ultrasound in the lung

We have previously described the induction of subcapsular hemorrhage in the murine lung by extracorporeal shock wave lithotripsy at exposures of 2 MPa (Hartman et al. 1990) and pulsed ultrasound (Child et al. 1990). Since extravasation of erythrocytes and alveolar flooding are prominent, we proposed to determine whether or not the injury was progressive, by continuing to develop following termination of exposure, and by localizing where the injury was developing. Mice were exposed to 10 microsecond impulses at 1.6 MPa for 3 min and sacrificed either immediately or 5 min following exposure. When observed with both light and transmission electron microscopy, there was no gradation in lung injury, with a sharp demarcation of the hemorrhagic area. Moreover, both type I pneumocytes and capillary endothelial cells were injured, causing direct continuities between vessel lumina and alveolar spaces. In the absence of extravasation, the tissue appeared normal. There was no evidence that injury increased in severity during the first 5 min after exposure.

Expression of alpha 6 beta 1 integrin, the laminin receptor, on subsets of normal murine lung fibroblasts and its upregulation by the inflammatory cytokines IFN-gamma and TNF-alpha

The purpose of this investigation was to ascertain whether the alpha 6 integrin subunit was present on normal murine lung cells and fibroblasts, and if so, to determine the identity of the beta subunit coordinately expressed with alpha 6 and whether or not these integrin subunits could be regulated by cytokines. Previously, our laboratory isolated populations of Thy 1+ and Thy 1- fibroblasts from normal murine lung tissue. These cells differed in surface marker expression and in response to, and production of, pro-inflammatory cytokines. Research defining the properties of these two populations has led to the hypothesis that unique groups of fibroblasts exist within the murine lung. Though alpha 6 beta 1 is known to be expressed by platelets, lymphocytes, and epithelial cells, its presence and regulation on lung fibroblast subsets has not been explored. We now report the following findings: 1) the laminin receptor, alpha 6 beta 1, is present on 20-30% of freshly isolated normal murine lung cells in all three murine strains tested; 2) established Thy 1+ and Thy 1- murine lung fibroblast subsets and clones constitutively express alpha 6 beta 1 at varied levels; and 3) alpha 6 beta 1 expression on fibroblast lines and clones can be upregulated by treatment with IFN-gamma or TNF-alpha. Since these T cell and macrophage derived cytokines are known to be present during an inflammatory response, upregulation of alpha 6 beta 1 expression may facilitate recruitment and retention of lung fibroblasts in regions undergoing repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential collagen and fibronectin production by Thy 1+ and Thy 1- lung fibroblast subpopulations

Pulmonary fibrosis resulting from diverse etiologies is characterized by proliferation of fibroblasts and excessive accumulation of interstitial collagen. Whether fibrosis is associated with selective expansion of fibroblast subpopulations differing in amounts or types of collagens synthesized is unknown. We have previously isolated lines and clones of normal murine lung fibroblasts based on the presence of the Thy 1 surface antigen. These subpopulations differ in morphology, growth characteristics, and display of class II major histocompatibility complex antigens (R.P. Phipps, D.P. Penney, P. Keng, H. Quill, A. Paxhia, S. Derdak, and M. E. Felch. Am. J. Respir. Cell Mol. Biol. 1: 65-74, 1989). We evaluated the amounts and types of collagen and fibronectin synthesized by Thy 1+ (Fib2-T-3+) and Thy 1- (Fib2-T-4-) lung fibroblast lines and clones. Thy 1+ fibroblast line synthesized two- to threefold more collagen and noncollagen protein than the Thy 1- line. In contrast, both the Thy 1+ and Thy 1- lines synthesized similar amounts of fibronectin. Thy 1+ and Thy 1- lines and clones expressed mRNA for alpha 1(I)-and alpha 1(III)-procollagen and synthesized both types (predominantly type I and lesser amounts of type III) of collagen, protein, and mRNA. The fibroblast clones varied significantly in total collagen and fibronectin production, with one Thy 1- clone (D3) synthesizing the largest amount of collagen but relatively little fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)

Cat tracheal gland cells in primary culture

Conditions for the primary culture of isolated cat tracheal gland cells were established. Cells plated onto glutaraldehyde-fixed gels of rat tail collagen grew to confluency after 8 days of culture forming a monolayer of cuboidal cells with ultrastructural characteristics of epithelial cells and immunoreactivity to antikeratins. Cultured cells synthesized and released radiolabeled high-molecular-weight glycoconjugates. Glycoconjugate secretion was increased approximately 10% in response to the cholinergic agonist, carbachol. Secretion of glycoconjugates was unrelated to regulated exocrine secretion, since these cells were devoid of secretion granules as assessed by light and electron microscopy. Confluent cultures also generated a spontaneous potential difference and short-circuit current, which were both inhibited by ouabain and increased by carbachol. This suggested gland cells contribute to fluid secretion by active ion-transport mechanisms. We also plated cells onto unfixed collagen gels that were released from the culture dish at confluency. Cells were columnar with apically oriented secretion granules that stained with alcian blue and for blood group A immunoreactivity. Secretion of radiolabeled high-molecular-weight glycoconjugates was increased 27% by carbachol. These cell culture systems may serve as models to investigate glandular secretory mechanisms and their regulation.

Pulmonary retention of ultrafine and fine particles in rats

In aerosol research, particle size has been mainly considered in the context of the role it plays in particle deposition along the respiratory tract. The possibility that the primary particle size may affect the fate of particles after they are deposited was explored in this study. Rats were exposed for 12 wk to aerosolized ultrafine (integral of 21 nm diameter) or fine (integral of 250 nm diameter) titanium dioxide (TiO2) particles. Other rats were exposed to TiO2 particles of various sizes (12, 21, 230, and 250 nm) by intratracheal instillation. After the rat lungs were extensively lavaged, analysis of particle content in the lavaged lungs, lavage fluid, and of lymphatic nodes was performed. Electron and light microscopy was also performed using unlavaged lungs. Both acute instillation and subchronic inhalation studies showed that ultrafine particles (integral of 20 nm) at equivalent masses access the pulmonary interstitium to a larger extent than fine particles (integral of 250 nm). An increasing dose in terms of particle numbers and a decreasing particle size promoted particle access into the interstitium. The translocation of particles into the interstitium appeared to be a function of the number of particles, and the process appeared to be related to the particle size, the delivered dose, and the delivered dose rate. A net effect of the preferential translocation of the smaller particles into the interstitium was a prolongation in their lung retention. After the 12-wk inhalation exposure, pulmonary clearance of ultrafine particles was slower (t1/2 = 501 days) than of larger particles (t1/2 = 174 days).(ABSTRACT TRUNCATED AT 250 WORDS)

Morphologic and functional characteristics of subpopulations of murine lung fibroblasts grown in vitro

Fibrotic development is a common response of the lung to toxic or deleterious insult. For example, the lung is the dose-limiting organ for irradiation of the thorax for primary or metastatic lesions, due in large part to latent fibrosis. The development of the fibrotic response reflects a cascade of cell-cell and cell-extracellular matrix interactions, the ultimate target of which is the fibroblast. There is increasing evidence of subpopulations of pulmonary fibroblasts, which may have differing roles in either the initiation or progression of fibrosis. Recently we described two fibroblast subpopulations from the murine lung, which differ in the presence or absence of the membrane antigen Thy-1 (Phipps et al., 1989). These Thy-1+ and Thy-1- subpopulations are stable and differ in certain functions, such as the production of cytokines and the display of Class II MHC antigens. To determine the morphologic development of the two subpopulations and their growth characteristics in vitro, cultures of the two cell subtypes were prepared for transmission and scanning electron microscopy at varying stages of growth. Thy-1+ fibroblasts are more spindle-shaped, contain intracellular lipid, exhibit abundant cell-cell contacts, and are capable of secreting large amounts of collagen and modest amounts of fibronectin. Thy-1- fibroblasts are more rounded and spread, contain no intracellular lipid droplets, possess more intracellular microfilaments and microtubules, and synthesize less collagen and more fibronectin than do Thy-1+ cells. There are no significant differences between the two subpopulations insofar as growth rates are concerned, but Thy-1+ fibroblasts possess an additional DNA peak during periods of early growth.

Ultrasonic heating of lung tissue

Tests with mice show that lung tissue is not selectively heated in comparison with other soft tissues and that lung has an efficient mechanism for dissipating that heat which is produced. Temperatures measured with a fine thermocouple placed at the outer surface of the mouse lung show approximately 1 degree C total rise in temperature in the living animal for an incident intensity of 1 W/cm2 (4 MHz, unfocused sound field).

Differential effects of oxygen and barotrauma on lung injury in the neonatal piglet

In order to differentiate the effects of hyperoxia and barotrauma in the pathogenesis of acute neonatal lung injury, piglets were either hyperventilated (Paco2, 15-20 torr) for 48 hours with 100% oxygen (Group I), hyperventilated with 21% oxygen (Group II), normally ventilated (Paco2, 40-45 torr) with 100% oxygen (Group III), or normally ventilated with 21% O2 (Group IV) and compared to unventilated controls. Pulmonary function was tested, and biochemical indicators of lung injury were analyzed in tracheo-bronchial aspirates at 0, 24, and 48 hours. Bronchoalveolar lavage fluid was analyzed for surfactant composition and activity at the end of the study. At 48 hours, hyperoxic, hyperventilated piglets had significantly decreased dynamic lung compliance (30%) and increased pulmonary resistance (16%), aspirate cell count (190%), elastase activity (88%), albumin (214%), and total protein (150%) concentration. Qualitative light microscopy showed moderate to severe atelectasis, fibrinous exudate, edema, and inflammation. Normoxic, hyperventilated animals had comparable changes in pulmonary mechanics, but significantly milder cellular, biochemical, and morphologic changes. In hyperoxic, normocarbic animals pulmonary physiologic, cellular, and biochemical variables changed comparably to hyperoxic, hyperventilated animals; the pathologic changes were intermediate between hyperoxic, hyperventilated and normoxic, hyperventilated piglets. Normoxic, normocarbic animals had no significant changes in most variables over 48 hours; on morphologic examination their lungs were similar to unventilated controls and showed only mild edema. Surfactant had normal biophysical activity in all animals. Our results demonstrate that hyperoxia causes more significant physiologic, inflammatory, and histologic changes than barotrauma alone. Future attempts to prevent lung injury in neonates should be directed primarily at oxygen toxicity.

Differentiation patterns in two- and three-dimensional culture systems of human squamous carcinoma cell lines

Relative quantification of the pattern of differentiation of two squamous carcinoma cell lines of the female genital tract, A431 and CaSki, was studied in various experimental tissue culture states that are frequently used to evaluate drug and radiation effects on human tumors. Two- and three-dimensional in vitro cultures, ie, monolayers and multicellular tumor spheroids (MCTS), and nude mice-xenograft tumors as in vivo tumor models were compared. In addition, epidermal growth factor (EGF) was used comparatively in the in vitro studies. Morphologic signs of epithelial differentiation could be recognized in both cell lines gradually increasing from monolayers to MCTS to xenograft tumors. Cytokeratin (CK) expression is described as stable in A431 cells. Using immunohistochemistry, however, partial masking of CK antigens was found when applying the antibody 8.12 on monolayer cells and could be quantified by flow cytometric measurements. Fundamental cellular changes were found in a CaSki xenograft tumor, which showed newly established features of a keratinizing carcinoma after late onset of tumor growth. Epidermal growth factor caused reduction of both intercellular contacts and later onset of necrosis in MCTS, leading to an increased viability of the spheroids. Significant differences in differentiation of the tumor model systems indicates that the characterization of differentiation with immunohistochemistry and flow cytometry is necessary to assist interpretation of data obtained with these different tumor models.

Differential expression of interleukin 1 alpha by Thy-1+ and Thy-1- lung fibroblast subpopulations: enhancement of interleukin 1 alpha production by tumor necrosis factor-alpha

The purpose of this investigation was to determine whether subpopulations of murine lung fibroblasts produced interleukin 1 (IL 1). We previously identified two major populations of pulmonary fibroblasts based on the presence or absence of Thy-1. Thy-1+ and Thy-1- subsets synthesize fibronectin and type I and III collagen, but only the Thy-1- population displays class II major histocompatibility complex antigens after stimulation with interferon-gamma and presents antigen to T helper clones. Interestingly, in the current study we determined that only Thy-1- fibroblast lines and clones synthesized IL 1. Although constitutive production was low, tumor necrosis factor -alpha (TNF-alpha) stimulated 5-20-fold increases in IL 1 production in Thy-1- fibroblasts. The Thy-1+ fibroblasts did not produce IL 1 even after TNF-alpha treatment. Northern blot analysis of TNF-alpha treated cells revealed that in the Thy-1- subset increased mRNA levels for IL 1 alpha were detected, while IL 1 beta mRNA was not detected. Furthermore, IL 1 activity from TNF-alpha-treated Thy-1- fibroblast membranes and supernatants was completely neutralized by IL 1 alpha-specific antibodies. These observations support the hypothesis that the antigen-presenting Thy-1- subset is important for promoting the inflammation associated with pulmonary fibrosis. In addition, the existence of functional subsets of lung fibroblasts is further substantiated by differential expression of IL 1.

Early pulmonary changes associated with high-frequency jet ventilation in newborn piglets

To assess the short-term effects of high-frequency jet ventilation (HFJV) on the neonatal lung, 28 newborn piglets were studied. Nine piglets were unventilated except during brief pulmonary measurements, nine animals were conventionally ventilated (arterial CO2 tension 35-45 torr, arterial O2 tension 70-80 torr) for 4 h, and 10 piglets were ventilated with HFJV for the same period. Pulmonary function was analyzed using a computerized technique and tracheobronchial aspirates were examined for biochemical indicators of lung injury; after 4 h, bronchoalveolar lavage was obtained for surfactant composition and activity, and lung sections were examined by light and electron microscopy. Results showed that HFJV provided adequate ventilation at lower inspiratory pressure compared with conventional ventilation (8.6 +/- 0.3 versus 13.8 +/- 1.3 cm H2O; p less than 0.01), while pulmonary mechanics did not vary significantly among the three animal groups. Tracheobronchial aspirates from HFJV animals had higher elastase activity versus unventilated piglets (118.5 +/- 14.1 versus 57.7 +/- 8.4 micrograms/mL; p less than 0.01), as well as higher albumin concentration versus unventilated animals (94.2 +/- 18.7 versus 23.2 +/- 6.5 micrograms/mL; p less than 0.01). In addition, there were small but statistically significant differences between all three groups in the distribution of surfactant phospholipids in bronchoalveolar lavage, although biophysical activity was normal. Scanning electron microscopy revealed flattening of Clara cells in the terminal bronchioles of HFJV animals due to loss of glycogen and secretory granules. These data indicate that despite lower peak inspiratory pressures, HFJV can cause subtle biochemical changes in lungs. Further studies are indicated to determine if these changes precede significant lung injury.

Electron microscopic identification and morphologic preservation of enriched populations of lung cells isolated by laser flow cytometry and cell sorting: a new technique

There is increasing need to verify the identities of cell subpopulations enriched by laser flow cytometry and fluorescence-activated cell sorting (FACS). When cell subpopulations isolated from whole organs or tissues have similar characteristics (e.g., size, granularity, staining), light, phase contrast or fluorescence microscopy may not provide sufficient resolution to identify isolated cells accurately and many flow cytometric parameters (e.g., viability, fluorescence) require the cells to be live at the point of analysis where the cell transects the laser beam. In some studies, cells identified by fluorescence microscopy as a highly enriched subpopulation were found by electron microscopy to contain significant populations of other cell types. A technique, fixation-in-flow (FIF), has been developed to increase ability to correlate morphological and laser analyses of cell subpopulations. Sheath fluid is replaced by fixative, permitting fixation to be initiated immediately after laser beam analysis of live cells. This new procedure yields improved cytoarchitectural preservation of recovered cell subpopulation(s) for evaluation by transmission or scanning electron microscopy. This report presents results from applying the methodology to identify more accurately cell subpopulations of the distal lung, specifically type II pneumocytes, Clara cells and pulmonary macrophages. A modification of this procedure was employed to isolate fibroblast subpopulations from murine lung fibroblasts grown in vitro and the procedure is being used to determine the responses of cultured fibroblasts to other permutations (e.g., X-irradiation, cytokines).

Lung injury in the neonatal piglet caused by hyperoxia and mechanical ventilation

Neonatal lung injury from hyperoxia and mechanical hyperventilation was studied in newborn piglets hyperventilated (arterial PCO2 15-20 Torr) for 24-48 h with 100% O2 and compared with unventilated controls. Pulmonary function testing was performed, and biochemical indicators of lung injury were analyzed from tracheobronchial aspirates at 0, 24, and 48 h. Lung sections were obtained for light and electron microscopy, and bronchoalveolar lavage fluid was analyzed for surfactant composition and activity. At 24 h significant changes in tracheobronchial aspirate albumin concentrations (up 78%) and percent of polymorphonuclear cells (up 16%) were demonstrated. At 48 h a 35% decrease in dynamic lung compliance (P less than 0.05) and a 36% increase in pulmonary resistance (P less than 0.05) were noted. Further biochemical abnormalities occurred with total cell counts increased by 271% (P less than 0.02), albumin 163% (P less than 0.05), total protein 217% (P less than 0.01), and elastase 108% (P less than 0.02). Pathological analyses revealed mild lung injury at 24 h and marked inflammation, abnormal inflation patterns, flattening of Clara cells, fibrinous exudate and edema, early collagen formation, and cell necrosis observed at 48 h. Bronchoalveolar lavage surfactant had normal biophysical activity. Results demonstrate that exposure of neonatal piglets to O2 and mechanical hyperventilation for 48 h cause severe progressive lung injury.

Characterization of two major populations of lung fibroblasts: distinguishing morphology and discordant display of Thy 1 and class II MHC

We have determined that murine lung fibroblasts are divisible into two major subpopulations based on expression of Thy 1. Twenty-four to fifty-three percent of freshly isolated lung cells displayed Thy 1 and were separated using FACS into Thy 1+ and Thy 1- fractions for morphologic examination. Analysis by electron microscopy revealed that both the Thy 1+ and Thy 1- fractions contained fibroblasts. Freshly isolated lung cells cultured for 2 wk consisted of greater than 95% fibroblasts, with 28 to 49% displaying Thy 1. These cells were sorted by FACS into Thy 1+ and Thy 1- lines that maintained a stable phenotype over many weeks and that were used as a source to obtain stable fibroblast clones. Adherent pulmonary fibroblasts are not phagocytic and lack the markers of macrophages, dendritic cells, B lymphocytes, and T lymphocytes (with the exception of Thy 1). Interestingly, the Thy 1- fibroblasts spread more and contained a more extensive microfilament and microtubule network than did the spindly and often lipid-containing Thy 1+ population. Both populations of fibroblasts synthesized collagen. Class I MHC expression was very low on Thy 1+ and Thy 1- fibroblasts, but high levels were displayed after gamma-IFN treatment. Most exciting was the unexpected finding that only the Thy 1- lines and clones displayed class II MHC (Ia) in response to treatment with gamma-IFN. Moreover, only the Thy 1- fraction (gamma-IFN-treated) presented antigen to T lymphocyte clones, an observation that suggests that this subset of cells may be involved primarily in promoting chronic lung inflammation, which is associated with developing fibrosis. Thus, two populations of pulmonary fibroblasts exist, defined by the expression of Thy 1, distinguishing morphology, inducibility for Ia expression, and antigen-presenting function. It should now be possible, using these characteristics, to ascertain the role of pulmonary fibroblast subpopulations in developing fibrosis.

Effect of thiol manipulation on chemopotentiation by nitroimidazoles

Highly electron affinic compounds such as the nitroimidazole misonidazole (MISO) have been shown both in vitro and in vivo to be effective potentiators of certain conventional chemotherapeutic agents. Mechanistically, the observation that nitroheterocyclics reduce intra-cellular thiols by enhancing the oxidation of glutathione (GSH), has suggested that thiol depletion by MISO may be a key factor in this enhancement. The present investigations were undertaken to determine whether the use of buthionine sulfoximine (BSO) to affect GSH metabolism may lead to more effective potentiation of chemotherapeutic agents by sensitizers. KHT/iv cells were treated in exponential phase under hypoxic conditions with variable doses of the activated form of cyclophosphamide (4-hydroxy-cyclo-phosphamide, 4OH-CY) administered concomitantly with or without MISO (2.5 mM) for an exposure time of 4 hr. Inclusion of the sensitizer in the treatment protocol resulted in a dose modifying factor of approximately 2.4. Exposing cells to 1.0 mM BSO for 2 hr prior to treatment reduced intracellular GSH levels to 70-80% of control and increased the efficacy of 40H-CY approximately 1.2-fold. If BSO was administered prior to the 4OH-CY + MISO combination, severe tumor cell toxicity resulted. For example, when combined with 4OH-CY, similar cell kill could be achieved with 5 to 6-fold lower MISO doses in the presence of BSO as in the absence of BSO. Ultrastructural evaluations revealed that in the three agent combination, membrane damage, as reflected by the formation of surface blebs, may play a key role in the mechanism of the observed enhanced cytotoxicity.

The ultrastructure of epithelial cells of the distal lung

This review has focused on the structural and functional characteristics of those epithelial cells that line the walls of the lower respiratory bronchioles, alveolar ducts, and alveoli. In all, five cells types were considered: Clara cells, types I, II, and III pneumocytes, and alveolar macrophages. In addition, a very brief mention of the structure and influence of the basement membrane in alveolar development and repair was included, as well as a brief review of the role of epithelial cells in response to selected deleterious influences. No attempt was made to extend this review to cover the structure and functions of the epithelial lining of the conducting portions of the respiratory system, or the exciting and expanding complexities and interrelationships of the septal stroma. Since the volume of literature encircling this subject has virtually exploded during the last 15 years, it becomes almost impossible to review all reports. However, attempts were made to be selective in citations. Insofar as future developments are concerned, much remains to be understood concerning (1) the responses of all cell types to cytotoxic influences, including their respective abilities to repair induced damage, (2) cell-cell and cell-extracellular matrix relationships in response to injury, (3) the uniqueness of the basement membrane in the lung in controlling permeability and gaseous exchange, (4) the role(s) of alveolar macrophages in response to injury and their relationships to the septal macrophage population, (5) the aberrations in the respective cell types that can give rise to neoplastic growth, and (6) the role of the immune system in responding to the general defense of the lung. Indeed much has been learned in the past 2 decades, and it is expected that a review of this sort 1 or 2 decades hence will elucidate many of the functions and structural modifications of the lung.

Effects of high energy particle (HZE) radiation on the distal lung

Major sources of concern for manned space travel are the effects of high energy particle (HZE) radiation on various biological systems, and the consequences of major solar activity. To date, considerable attention has been directed toward HZE-induced alterations both on non-dividing systems, such as the retina, cornea and brain, and on dividing systems, such as the gut and testis. This paper is focused on the morphologically detectable late-occurring alterations in the distal lung, and toward a comparison of the changes with those induced by x-irradiation. Briefly, the salient alterations involve an increase in the width of the septal walls and the capillary and alveolar basal laminae, and the irregularity of the luminal surface of the capillaries, as exemplified by the presence of filipodial projections and blebbing. All alterations were focal in their localization, and no cells of any type (e.g., epithelial, endothelial or stromal) appeared to undergo damage, an observation quite unlike the cellular changes induced by x-irradiation.

Cell-cell matrix interactions in induced lung injury. IV. Quantitative alterations in pulmonary fibronectin and laminin following X irradiation

Male LAF/1 mice were locally irradiated at doses of 5, 9, and 13 Gy and compared with untreated and sham-irradiated animals. Lungs were subsequently examined at times of 1, 4, 13, 28, 41, and 63 weeks postirradiation (PI) for alterations in pulmonary fibronectin (Fbn) and laminin (Lam) as a consequence of the irradiation. Thoroughly perfused lungs dissected clear of major airways were homogenized and fractionated by centrifugation into two fractions, soluble (supernate) and insoluble (pellet). Each fraction was analyzed by nonequilibrium competitive enzyme-linked immunoassay (ELISA) for Fbn and Lam normalized to mg protein. The results show a dose-related increase in soluble Fbn demonstrable at 1 week PI and approaching seven times control values by 28 weeks for doses of 13 Gy. Thereafter amounts decrease steadily to 63 weeks. Insoluble Fbn remains at or near control values through 13 weeks, increases in a dose-related fashion almost fivefold by 41 weeks for doses of 13 Gy, and then decreases by 63 weeks. Soluble Lam increased slightly during the duration of the study, returning to normal by 63 weeks. Insoluble Lam shows a dose-dependent increase demonstrable at 4 weeks PI which continues through 63 weeks. Interactions between these alterations in Fbn and Lam and previously reported changes in basal laminar proteoglycans may, in concert with other cellular and extracellular components, relate to the initiation and/or maintenance of radiation-induced pulmonary fibrosis.

31P-NMR spectroscopy demonstrates decreased ATP levels in vivo as an early response to photodynamic therapy

31P-Nuclear magnetic resonance was used to monitor in situ phosphorus containing compounds in mammary tumors after photodynamic therapy, consisting of administration of hematoporphyrin derivative followed by photoradiation of the lesion. A rapid decrease in ATP along with an increase in Pi resonance intensities was observed. The beta-ATP/Pi ratio decreased by 1 hour, dropping in 2 to 8 hours to 0 to 20 percent of that found prior to photoradiation. Disrupted cells and pycnotic nuclei were observed 48 to 72 hours after photoradiation to a depth of approximately 5 mm. Together with previous studies in vitro, reduction in tumor ATP levels appears to be an early biochemical response to photodynamic therapy.

Cell-cell matrix interactions in induced lung injury: III. Long term effects of X-irradiation on basal laminar proteoglycans

The lungs of male LAF1 mice were locally irradiated with doses of 5, 9, and 13 Gy. The animals were killed at times corresponding to the appearance of histologically identifiable fibrosis or, for 13 Gy, at the LD50 for these doses and strain of mouse: 63, 36, and 28 weeks postirradiation (PI) respectively. Lungs were excised, incubated in buffer alone, or partially digested with enzymes for determination of relative glycosidase resistance, fixed with ruthenium red/Triton X-100 for demonstration of basal laminar anionic sites, and processed for electron microscopy. Sham-irradiated and untreated control groups (0 Gy, 0 times) were also processed. Tissue was examined ultrastructurally and alterations in both alveolar and capillary basal laminar anionic sites were quantitated. In each of the doses examined the number of anionic sites surpassed normal levels; however, the glycosidase resistance of the regenerated laminae at these late time points was not significantly altered from controls. This contrasts with the marked increase in the glycosidase resistance of laminae regenerating from radiation damage (4-12 weeks PI) reported earlier. The increased numbers of anionic sites were compared to expected values derived from models based on compensatory synthesis and continued accumulation and indicate close correlation with certain aspects of the compensatory synthesis model but not with others. The effects on basal laminar permeability, basal laminar thickening, and fibrotic induction are discussed.

Predictive biochemical assays for late radiation effects

Surfactant precursors or other products of Type II pneumocytes have the potential to be the first biochemical marker for late radiation effects. This is particularly clinically important in the combined modality era because of the frequent occurrence of pneumonitis and pulmonary fibrosis secondary to radiation or chemotherapy. Accordingly, correlative studies have been pursued with the Type II pneumocyte as a beginning point to understand the complex pathophysiology of radiation pneumonitis and fibrosis. From our ultrastructural and biochemical studies, it is evident that Type II pneumocytes are an early target of radiation and the release of surfactant into the alveolus shortly after exposure persists for days and weeks. Through the use of lavaging techniques, alveolar surfactant has been elevated after pulmonary irradiation. In three murine strains and in the rabbit, there is a strong correlation with surfactant release at 7 and/or 28 days in vivo with later lethality in months. In vitro studies using cultures of type II pneumocytes also demonstrate dose response and tolerance factors that are comparable to the in vivo small and large animal diagnostic models. New markers are being developed to serve as a predictive index for later lethal pneumonopathies. With the development of these techniques, the search for early biochemical markers in man have been undertaken. Through the use of biochemical, histological, and ultrastructural techniques, a causal relationship between radiation effects on type II pneumocytes, pulmonary cells, endothelial cells of blood vessels, and their roles in the production of pneumonitis and fibrosis will evolve.

Adsorption of natural lung surfactant and phospholipid extracts related to tubular myelin formation

The microstructure of aqueous dispersions of pulmonary surfactant lipids extracted from bovine lung lavage was investigated by electron microscopic analysis. Following organic solvent extraction (chloroform/methanol) from natural lung surfactant, the mixed lipids (CLL), with 1% residual protein, were dispersed in water by two techniques, probe sonication at 4 degrees C and mechanical vortexing. Surface pressure-time adsorption isotherms were defined for the CLL dispersions, followed by staining with tannic acid, uranyl acetate, and lead citrate for electron microscopy of microstructure. CLL extract dispersions adsorbed in seconds to surface pressures near 45 dynes/cm (surface tension 25 dynes/cm) at low concentrations less than or equal to 0.25 mg/ml after dispersion by sonication of 4 degrees C and by mechanical vortexing. Ultrastructurally, the CLL dispersions were somewhat heterogeneous, but large thin-walled phospholipid vesicles, both intact and fragmented, predominated. No tubular myelin was formed. By contrast, natural lung surfactant (LS) from bronchoalveolar lavage had characteristic regions of tubular myelin when it adsorbed well at low concentrations (less than or equal to 0.25 mg phospholipid/ml). When divalent cations were removed from solution with 5 mM EDTA, this distinctive microstructure was not present and natural LS adsorbed less rapidly; higher concentrations of 0.63 mg phospholipid/ml were necessary for maximal adsorption of natural LS without tubular myelin. These results suggest that while tubular myelin is associated with optimal adsorption for natural LS, it is not a required configuration for rapid adsorption facility at low phospholipid concentrations in general. Specifically, for dispersions of surfactant extracts, other microstructures allow adsorption facility equivalent to that of natural LS with tubular myelin.

Cyclophosphamide-induced pulmonary toxicity

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Cell-cell matrix interactions in induced lung injury. II. X-irradiation mediated changes in specific basal laminar glycosaminoglycans

The thoraces of male LAF1 mice were irradiated at doses of 5, 9, or 13 Gy. The animals were killed at times of 1 hr, 1 day, 1 wk, 4 wks, and 12 wks postirradiation (PI). The lungs were removed, enzymatically or detergent digested, fixed with ruthenium red for demonstration of anionic sites, and processed for electron microscopy. Untreated (0 Gy, 0 time) and sham irradiated control groups were also processed. Sections of lungs were examined and changes in alveolar basal laminar anionic sites were quantitated. Changes in three groups of glycosaminoglycans (GAGs) were identified: chondroitin 4 and 6 sulfate-dermatan sulfate, hyaluronate, and other GAGs (principally heparan sulfate). At 1 hr PI, all groups showed a marked decrease in site number over controls, which continued to 1 wk. By 4 wks there was a marked relative increase in heparan sulfate containing sites for doses of 13 Gy and a moderate increase for the other doses. At 12 wks the level of heparan sulfate was considerably above normal for doses of 13 Gy and just above normal for the other doses. Chondroitin-dermatan sulfate had recovered by 12 wks for doses of 13 Gy, but was still subnormal for other doses; however, hyaluronate-containing sites recovered only slightly by 12 wks. The implications for this change on basal laminar permeability and the induction of fibrosis are discussed.

Cell-cell matrix interactions in induced lung injury. I. The effects of X-irradiation on basal laminar proteoglycans

The lungs of male LAF1/J mice were locally irradiated with graded doses of radiation ranging from 5 to 13 Gy. The animals were sacrificed at 1 hr, 1 day, 1 week, 4 weeks, and 12 weeks postirradiation (PI), fixed with Ruthenium Red/Triton X-100 for demonstration of basal laminar anionic sites, and processed for electron microscopy. Sham-irradiated (0 Gy, 0 time) and untreated control groups were also processed. Sections of lungs were examined ultrastructurally and changes in both alveolar and capillary basal laminar anionic sites quantitated. A marked decrease in the number of basal laminar anionic sites was noted 1 hr PI in both alveolar and capillary basal laminae at all dose levels. The decline continued to 1 week for doses of 13 Gy and more gradually to 4 weeks following doses of 5 and 9 Gy, when the number of sites began to increase. By 12 weeks animals receiving 13 Gy were approaching normal levels while those receiving 5 or 9 Gy remained subnormal. The potential effects of the loss of proteoglycans with radiation on lung basal laminar permeability and cell-extracellular matrix interactions are discussed.

Somatic cell hybridization of human tumor samples

Human intraspecific hybrids were formed between tumor cells isolated from both primary and metastatic tumors and a tissue culture adapted cell line, D98OR, a HeLa derivative which is thioguanine and ouabain resistant. Five different tumor types in all were attempted: renal cell carcinoma, colon adenocarcinoma, melanoma, chrondrosarcoma, and hepatocarcinoma. The tumor tissue was either (1) immediately dissociated and fused, or (2) frozen and later thawed, dissociated, and fused. Two different PEG concentrations were used. The results reported here demonstrate that: (1) hybrid tumor cell lines can be made from several types of cancer, (2) unfrozen tumor tissue fused with D98OR by exposure to 50% PEG appears optimal, (3) chromosome loss, as determined by flow cytometry studies of hybrid DNA content, is minimal, and (4) hybrids have characteristics consistent with derivation from tumor cells rather than derivation from the nonmalignant cells of a tumor.

Radiation induced secretion of surfactant from cell cultures of type II pneumocytes: An in vitro model of radiation toxicity

The pathogenesis of pneumonitis and fibrosis secondary to lung irradiation is incompletely understood. The role of the type II alveolar epithelial pneumocyte in these processes has been under investigation. The type II pneumocyte has been shown in vivo to respond to radiation induced injury with release of pulmonary surfactant. The effect of irradiation on cell cultures of type II pneumocytes was studied to determine if this could be reproduced in vitro. Type II pneumocytes were found to release surfactant material with a threshold of radiation dose between 1000 and 1500 rad. This is similar to the dosage range over which the same effect has been demonstrated in vivo. Experimental results support the concept that the release of surfactant is not due to either cell disruption or non-specific release of phospholipid from cell membranes. Irradiation appears to trigger membrane receptor mediated surfactant release. In addition, irradiation abolishes the ability of cells to subsequently respond to a physiologic agonist, suggesting radiation induced damage to the secretory mechanism. These studies establish that surfactant release in response to irradiation in vivo is a direct effect on type II pneumocytes. Cell cultures of type II pneumocytes can serve as a laboratory model of lung cell radiation toxicity.

Surfactant release as an early measure of radiation pneumonitis

The immediate release of surfactant into lung alveoli following irradiation has been studied as a potential indicator for the later development of radiation pneumonitis. Utilizing single dose radiation exposure to the whole thorax in male LAF1/J mice, steep dose response curves for lavaged alveolar surfactant were identified at 7 and 28 days after exposure. Seven days after irradiation there was no elevation with doses up to and including 12 Gy; above this dose a detectable increase occurred. At 28 days the surfactant recovered by lavage was elevated compared to the levels seen at day 7 for all doses; doses greater than 12 Gy produced surfactant values significantly greater than those found in mice treated with 12 Gy or less. The radiation pulmonary lethality dose response curve assessed four months later indicated an LD50 value of approximately 13 Gy. The early biochemical effect and the later radiation pneumonitis lethalities therefore closely coincided. The evidence strongly indicates that alveolar surfactant release uncovered hours to days after radiation exposure may be an early biochemical marker that predicts for subsequent pneumonitis radiation injury.

Ultrastructural immunocytochemical localization of fibronectin in the developing rat lung

In a previous study changes in the macrodistribution of fibronectin during rat-lung development were examined. Using the peroxidase-antiperoxidase immunocytochemical technique, we have demonstrated the presence of fibronectin in embryonic, neonatal, and adult rat lung at the ultrastructural level. In the embryo, fibronectin is found both in an intra- and extracellular association with isolated pneumoblasts, and in a periodic distribution along the basal lamina. The neonate displays fibronectin in an intracellular association with early type-I cells and on their basal and luminal surfaces, but not in association with type-II cells. Neonatal basal lamina is diffusely labeled by anti-fibronectin antiserum. Fibronectin in adult tissue is found both intracellularly and on the basal and luminal surfaces of type-I cells but not in type-II cells. The basal lamina and interstitial connective tissue are slightly or non-reactive. These observations confirm and extend our initial suggestion that fibronectin is involved in rat-lung development.