Hamster Lung Tissue Research Articles

Review article : A mathematical model of tumor growth. III. Comparison with experiment

In this paper a model of nonuniform inhibitor production is used to discuss some experimental results obtained by Folkman and Hochberg for multicellular spheroids (of V-79 Chinese hamster lung tissue). Built into mathematical model is a parameter b which is a measure of the degree of nonuniformity of the inhibitor production rate. The “inverse problem” is solved by finding the value of b necessary to account for results with which the uniform model is incompatible [6]. The resulting value of b enables a good estimate to be made for the observed width of peripheral mitotic zones in the V-79 spheroids, and the resulting stability parameters lie in approriate ranges for the model to be a significant improvement over uniform models. Further improvements are discussed, including a heuristic model for estimating the destabilizing effect of vascularization on tissue growth.

Effects of Intratracheal Instillation of Bleomycin on Phospholipid Synthesis in Hamster Lung Tissue Slices

Bleomycin, an antineoplastic drug, is known to produce interstitial pulmonary fibrosis (IPF). As a result, it is commonly employed in various species to produce animal models of fibrosis. We have examined the uptake of [14C]acetate by lung slices and its incorporation into lipids in the slices at various times following intratracheal administration of a fibrogenic dose (10 units/kg) of bleomycin in hamsters. As compared to saline controls, bleomycin had no effect on [14C]acetate uptake at 4 and 7 days but it increased the uptake at 2 and 14 days after treatment. The incorporation of [14C]acetate into total lipid was significantly reduced to 44, 62, 62, and 75% of the control at 2, 4, 7, and 14 days after bleomycin treatment, respectively. The incorporation into lipid as a percentage of the uptake was 12.2 in control animals whereas in bleomycin-treated animals, it was 4.7, 8.0, 7.3, and 6.9 at the corresponding times. Separation of lipids into various fractions revealed that bleomycin treatment specifically inhibited the synthesis of phosphatidylcholine and neutral lipid at all times of the study. The synthesis of all other phospholipids except phosphatidylethanolamine was depressed at 2 days. The latter was, however, depressed at 7 and 14 days after bleomycin treatment. It was concluded from the present study that bleomycin treatment inhibits the synthesis of phospholipid and neutral lipid and this may eventually lead to decreased surfactant production.

A mathematical model of tumor growth. III. comparison with experiment

In this paper a model of nonuniform inhibitor production is used to discuss some experimental results obtained by Folkman and Hochberg for multicellular spheroids (of V-79 Chinese hamster lung tissue). Built into the mathematical model is a parameter b which is a measure of the degree of nonuniformity of the inhibitor production rate. The “inverse problem” is solved by finding the value of b necessary to account for results with which the uniform model is incompatible [6]. The resulting value of b enables a good estimate to be made for the observed width of peripheral mitotic zones in the V-79 spheroids, and the resulting stability parameters lie in appropriate ranges for the model to be a significant improvement over uniform models. Further improvements are discussed, including a heuristic model for estimating the destabilizing effect of vascularization on tissue growth.

In vivo and in vitro hamster models in the assessment of virulence of recombinant influenza viruses

The virulence of five wild-type influenza A viruses and 14 recombinant viruses, prepared from the cold adapted A/Ann Arbor/6/60 virus and various wild-type viruses, was studied by two methods. Firstly, the viruses were inoculated into hamsters, and the titres present in the lungs and turbinates at 1, 3 and 4 days post-infection were measured. Secondly, the effect of five wild-type and ten recombinant viruses on the ciliated epithelium of in vitro hamster tracheal organ cultures was examined. The results obtained were assessed with reference to the known virulence of the viruses for human volunteers. The results showed that virus strains virulent for man grew to higher titres in hamster lungs and turbinates than attenuated strains; and that virulent strains destroyed the ciliary activity of hamster tracheal organ cultures more quickly and to a greater extent than attenuated strains. Comparison of the results with the known virulence of viruses tested for man suggests that the reduced ability of virus to grow in hamster lung tissue and the relatively little effect on ciliary activity may be used as markers of virus attenuation; however, the growth of virus in hamster turbinates overlaps for virulent and attenuated strains and therefore was not considered a useful marker of virulence.

Hemadsorption and virulence are separable properties of Mycoplasma pneumoniae.

A selective enrichment technique was used to isolate a hemadsorption-positive revertant of a hemadsorption-negative mutant strain of Mycoplasma pneumoniae. This hemadsorption-positive revertant was shown to have simultaneously regained both the ability to attach to neuraminidase-sensitive receptors on the tracheal ring respiratory epithelium in vitro and the ability to synthesize three virulent-strain-specific proteins which were not synthesized by the hemadsorption-negative mutant. Despite the persistence of the revertant in hamster lung tissue for 9 to 12 weeks postinfection, no cytopathology was observed. Intranasal inoculation of the revertant provided limited protection against a challenge dose of virulent M. pneumoniae.

Responses of pulmonary allograft and cheek pouch arterioles in the hamster to alterations in extravascular pressure in different oxygen environments.

The responses to changes in transmural pressure were investigated in pulmonary allograft and cheek pouch arterioles in two oxygen environments. Neonatal hamster lung tissue was transplanted into adult hamster cheek pouches. After vascularization (8-10 days), pulmonary and cheek pouch vessels were observed by intravital microscopy in hamsters anesthetized with pentobarbital. By gassing the suffusion solution (bicarbonate-buffered Ringer's) (pH 7.4 at 35-37 degrees C) with either low oxygen (95% N2/5% CO2) or high oxygen (75% N2/5% CO2/20% O2) and after sealing the top of the chamber, extravascular pressure was altered by varying the fluid volume of the closed chamber. Changes in arteriolar diameters in response to positive and negative square-wave pressure pulses were quantified using a video micrometer and close-circuit TV system. Pulmonary arterioles showed a passive dilation or constriction in response to increases or decreases in transmural pressure (+/-20 mm Hg). These responses were not altered either by changes in PO2 or nitroprusside. In contrast, cheek pouch arterioles showed myogenic responses by constricting when transmural pressure was increased and vice versa. These responses were potentiated at high PO2 and abolished with nitroprusside. It is concluded that a myogenic response is dominant in cheek pouch arterioles but not in pulmonary arterioles under these conditions. These latter observations are consistent with results obtained from isolated, intact lung.

The incorporation of choline into disaturated phosphatidylcholine in the microsomal, lamellar body, and surfactant fractions of hamster lung tissue.

The specific activity of disaturated phosphatidylcholine in microsomes and lamellar bodies prepared from hamster lung tissue and in surfactant obtained by lung lavage was determined at various times following the intraperitoneal administration of [Me-3H]choline. The highest specific activity of disaturated phosphatidylcholine in the lung microsomes was attained 1 h after the administration of [3H]choline; thereafter, the specific activity declined. The specific activity of disaturated phosphatidylcholine in lamellar bodies increased steadily for 12 h after [3H]choline administration. The specific activity in lamellar bodies ater 12 h exceeded the maximum specific activity achieved in the microsomal fraction (p less than 0.005). The specific activity of the disaturated phosphatidylcholine in the alveolar lavage increased after an initial lag period of approximately 3 h, attaining the same specific activity as that of the lamellar bodies at the 12-h time point. The reported results are discussed in relation to the biosynthesis, storage, and secretion of the disaturated phosphatidylcholine associated with the lipoprotein, surfactant.

Mucus and Surfactant Synthesis and Secretion by Cultured Hamster Respiratory Cells

Procedures for the selective isolation and cultivation in monolayer of respiratory cells have been developed. This technique requires repeated protease treatment and gradient centrifugation of hamster tracheal or lung tissues and permits the establishment of proliferating cultures of epithelial cells with biologic specialization. Mucus synthesis was monitored in cultured tracheal cells by incorporation of 3H-labeled N-acetyl-D-galactosamine and 14C-serine into glycoprotein as determined by trichloroacetic acid precipitation of growth medium followed by acrylamide gel electrophoresis. For comparative purposes tracheal explants and several established cell lines were also examined. Synthesis and secretion of the glycoprotein macromolecule by tracheal cell monolayers appeared to be regulated by vitamin A since its addition to the culture medium significantly increased both the number of cell-associated granules and glycoprotein secretion. Lung-originated cell cultures were grown to confluence and radio-labeled with 3H-choline in serum-free medium for 24 hr to examine surfactant synthesis. Cell monolayers and growth medium were then extracted by the Folch method, and total radioactive phosphatidylcholine as well as disaturated phosphatidylcholine were determined by thin-layer chromatography and alumina gel fractionation of osmium tetroxide-reactive phospholipid, respectively. Data indicate that these cultures have a marked ability to synthesize and secrete surfactant when compared to other established cell lines. In addition, naturally transformed cells that arose during passage and senescence of the primary cultures were analyzed for their biosynthetic capabilities.

Mutagenicity of beta-oxidized N,N,-di-n-propylnitrosamine derivatives in S. typhimurium mediated by rat and hamster tissues.

The relative abilities of liver, kidney and lung fractions from untreated or phenobarbitone-pretreated rats and hamsters to convert N,N-di-n-propylnitrosamine and several beta-oxidized synthetic putative intermediates into mutagens was quantitatively compared in a tissue-mediated mutagenicity assay with S. typhimurium TA 1530 in vitro. With one exception, namely, N,N-di(2-acetoxy-n-propyl)nitrosamine, liver was the most active tissue from hamsters; in rats also, only liver fractions were able to activate some nitroso-compounds to mutagens. The highest enzyme-mediated mutagenicities were observed with N-2-hydroxy-n-propyl-N-n-propylnitrosamine, N,N-di-n-propylnitrosamine and N,N-di(2-acetoxy-n-propyl)nitrosamine. Hamster lung tissue converted N,N-di-n-propylnitrosamine, N-2-hydroxy-n-propyl-N-n-propylnitrosamine and N,N-di(2-acetoxy-n-propyl)nitrosamine into mutagens; activity with the latter compound was greater with lung tissue than with liver tissue when untreated animals were used. N-methyl-N-n-propylnitrosamine was mutagenic in the presence of hamster liver fraction but less so than N,N-di-n-propylnitrosamine. The results of the mutagenicity assays using various tissues are qualitatively compared to sites of tumour formation in rats and hamsters by these N-nitrosamines.

Variation in susceptibility of different cell types to temperature-sensitive host range mutants of herpes simplex virus type 2

Four conditional lethal mutants of herpes simplex virus type 2 have been investigated for ability to induce cytopathic effects (CPE) and to replicate at 39° in various cell types. Epithelioid cell cultures were prepared from the kidneys of hamsters, mice, and rabbits; fibroblastoid cell cultures from hamster, mouse, rabbit, and human lung tissues. Parental virus and all mutants replicated in all cell types at 33° resulting in lysis of the cultures. At 39°, fibroblastoid cells of rodent origin were nonpermissive for the mutants. However, epithelioid cells, regardless of origin, and fibroblastoid cells derived from rabbit and human tissues were permissive to mutant virus replication at 39°. As the temperature-sensitive virus defect can be overcome in selected cell types, these mutants display host range and cell-type characteristics.

New approaches to the isolation of mycoplasmas.

Homogenates of rodent and human tissues after storage at 4°C for 72 h killedMycoplasma pulmonis. Lysolecithin also killed the organisms. Several ways of overcoming this mycoplasmacidal activity were investigated. Of these, success was achieved by the addition of ammonium reineckate or lysophospholipase to medium containing lysolecithin; mycoplasmacidal activity was abolished. These substances were then used in attempts to overcome the inhibitory activity of hamster lung tissue onM. pneumoniae organisms. The organisms were isolated from suspensions of the tissue that otherwise inhibited their growth. These results lend support to the idea that lysolecithin is important for the mycoplasmacidal activity of tissue homogenates and indicate the potential value in mycoplasma isolations of the commercially available compound, ammonium reineckate.

A comparison of the cardiovascular actions of daunomycin, adriamycin and N-acetyldaunomycin in hamsters and monkeys.

The most consistent initial effects of adriamycin (12.5–50.0 mg/kg) in hamsters and rhesus monkeys were bradycardia, hypotension, ventricular arrhythmias and respiratory depression. Daunomycin (50 mg/kg) produced ventricular arrhythmias at twice the dose of adriamycin. In both species large doses of N-acetyldaunomycin (200 mg/kg) caused only minimal changes in all parameters. Significant amounts of all 3 parent compounds were detected in hamster heart and lung tissues soon after injection. A relatively rapid conversion of both daunomycin and adriamycin to the aglycone was found, but a significantly higher percentage of the adriamycin aglycone was concentrated in these 2 tissues. In contrast, relatively little conversion of N-acetyldaunomycin was detected. Thus, the observed pharmacological actions may be related to differences in metabolism of the 3 compounds.

Morphological Conversion of Cells in vitro by N-Nitrosomethylurea

A system is described for investigating the primary events involved in the induction of tumours by certain chemical carcinogens. It is based on the finding that such compounds alter the mode of growth of cells from a Chinese hamster lung tissue cell line in culture, and that the effect accompanies an ability to cause tumours when such cells are later injected into foreign host animals.

Early effects by SV40 on growth in vitro of hamster and human tissue cells.

SummarySuspensions of cells derived from hamster embryonic and lung tissues soon after exposure to SV40 virus exhibited enhanced capacity to multiply in a soft agar medium. Such enhancement was not observed in human kidney cells similarly treated. Production of SV40 T antigen was seen in hamster embryo cells after 3-4 weeks and in human kidney cells after 8 weeks following exposure to the virus but was not observed at 3, 5 and 8 weeks in lung cells maintained under the same conditions.

X-ray damage and recovery in mammalian cells in culture.

Cells of hamster ovarian and lung tissues propagated in culture medium did not display heritable damage frora x irradiation. They repaired their accumulated damage before their iirst division after irradiation. Contexts in which the findings are of interest are discussed. (C.H.)