Trachea Explants Research Articles

South American H4N2 influenza A virus improved replication in chicken trachea after low number of passages.

Introduction of influenza A viruses (FLUAV) into poultry from waterfowl is frequent, producing economic burden and increasing the probability of human infections. We have previously described the presence of FLUAV in wild birds in Argentina with unique evolutionary trajectories belonging to a South American lineage different from the North American and Eurasian lineages. Adaptability of this South American lineage FLUAV to poultry species is still poorly understood. In the present report, we evaluated the capacity of an H4N2 FLUAV from the South American lineage to adapt to chickens after low number of passages. We found that five mutations were acquired after five passages in 3-days-old chickens. These mutations produced a virus with better infectivity in ex vivo trachea explants but overall lower infection in lung explants. Infection of 3-week-old chickens persisted for a longer period and was detected in more tissues than the parental virus, suggesting adaptation of the H4N2 influenza A virus to chicken.

Changes in the Hemagglutinin and Internal Gene Segments Were Needed for Human Seasonal H3 Influenza A Virus to Efficiently Infect and Replicate in Swine.

The current diversity of influenza A viruses (IAV) circulating in swine is largely a consequence of human-to-swine transmission events and consequent evolution in pigs. However, little is known about the requirements for human IAVs to transmit to and subsequently adapt in pigs. Novel human-like H3 viruses were detected in swine herds in the U.S. in 2012 and have continued to circulate and evolve in swine. We evaluated the contributions of gene segments on the ability of these viruses to infect pigs by using a series of in vitro models. For this purpose, reassortant viruses were generated by reverse genetics (rg) swapping the surface genes (hemagglutinin-HA and neuraminidase-NA) and internal gene segment backbones between a human-like H3N1 isolated from swine and a seasonal human H3N2 virus with common HA ancestry. Virus growth kinetics in porcine intestinal epithelial cells (SD-PJEC) and in ex-vivo porcine trachea explants were significantly reduced by replacing the swine-adapted HA with the human seasonal HA. Unlike the human HA, the swine-adapted HA demonstrated more abundant attachment to epithelial cells throughout the swine respiratory tract by virus histochemistry and increased entry into SD-PJEC swine cells. The human seasonal internal gene segments improved replication of the swine-adapted HA at 33 °C, but decreased replication at 40 °C. Although the HA was crucial for the infectivity in pigs and swine tissues, these results suggest that the adaptation of human seasonal H3 viruses to swine is multigenic and that the swine-adapted HA alone was not sufficient to confer the full phenotype of the wild-type swine-adapted virus.

Effect of Alarmins on the Synthesis of Tissue Cytokines

A primary response of the innate immune system to a pathogen invasion or tissue damage is the synthesis of tissue cytokines. Interleukins (IL) 25 and 33 or thymic stromal lymphopoietin (TSLP) are produced by epithelial or muscle cells in response to pathogen fragments, i.e., pathogen associated molecular patterns (PAMPs) or endogenous stress factors (danger associated molecular patterns, DAMPs). The goal of this work is to compare the ability of the bacterial peptide N-formyl-met-leu-phe (fMLP) and an endogenous pruritus inducer, amino acid β-alanine, to stimulate the expression of tissue cytokines. It has been shown by quantitative PCR that fMLP stimulates the ex vivo gene expression of TSLP and IL-25 in murine trachea explants, and β-alanine also stimulates IL-33 gene expression. The in vivo level of TSLP and IL-33 has been evaluated by ELISA in lung homogenates 1 and 6 h after intratracheal injection of the stimulants. Both β‑alanine and fMLP induce the release of IL-33 and TSLP from the intracellular depot. It is shown for the first time that β-alanine and fMLP are activators of tissue cytokine synthesis.

Absence of clinical disease and contact transmission of HPAI H5NX clade 2.3.4.4 from North America in experimentally infected pigs

BackgroundIn the fall of 2014, highly pathogenic avian influenza (HPAI) subtype H5N8 clade 2.3.4.4 was introduced into North America by migrating waterfowl from Asia where, through reassortment, novel HPAI H5N2 and H5N1 viruses emerged.ObjectivesAssess the susceptibility of pigs to HPAI H5N1, H5N2, and H5N8 clade 2.3.3.3 from North America.MethodsPigs and trachea explants were inoculated with a representative panel of H5NX clade 2.3.4.4 HPAI viruses from North America. Nasal swabs, BALF, and sera were collected to assess replication and transmission in challenged and direct contact pigs by RRT‐PCR, virus isolation, hemagglutination inhibition, and ELISA.ResultsLimited virus replication was restricted to the lower respiratory tract of challenged pigs, though absent in the nasal passages and trachea cultures, as determined by RRT‐PCR in all samples. Seroconversion of inoculated pigs was detected by NP ELISA but was not reliably detected by antigen‐specific hemagglutination inhibition. Boost with adjuvanted virus was required for the production of neutralizing antibodies to assess cross‐reactivity between wild‐type avian strains. All RRT‐PCR and serology tests were negative for contact animals indicating a failure of transmission from primary inoculated pigs.ConclusionsH5NX clade 2.3.4.4 strains can replicate in the lower respiratory tract of swine upon high titer inoculation, though appear to be incapable of replication in swine nasal epithelium in vivo or ex vivo in trachea explants in culture. Infected pigs did not produce high levels of serum antibodies following infection. Collectively, our data show HPAI H5NX clade 2.3.4.4 viruses to be poorly adapted for replication and transmission in swine.

7. Lentiviral Vector-Mediated CFTR Gene Transfer to CF Pig Airways Corrects the Anion Transport Defect In Vivo

Cystic fibrosis (CF) is the most common autosomal recessive disorder in Caucasian populations and is caused by mutations in CFTR. Complementation of CFTR rescues the anion transport defect in vitro, making this monogenetic disease a candidate for CF gene therapy. Lentiviral vector-mediated CFTR gene transfer has long been discussed as a promising strategy for gene therapy. Lentiviral vectors can efficiently transduce non-dividing cells and persistently express a therapeutic transgene. We previously demonstrated that the non-primate lentiviral vector derived from feline immunodeficiency virus (FIV) and pseudotyped with a GP64 envelope confers gene transfer to porcine airway epithelia both in well-differentiated primary cultures in vitro and in wild-type pig lungs in vivo. The CF pig model recapitulates many features of human disease and provides a new platform for preclinical gene therapy studies. Here, we show that lentiviral-mediated delivery of CFTR to nasal and lung epithelia corrects the anion channel defect in the CF pig model. We delivered GP64-FIV-pigCFTR to the nose and lung of 2-week old gut-corrected CF pigs using a MADgic atomizer. Two weeks post-transduction, we harvested sinus, trachea, and bronchus tissue to assay for gene correction. In freshly excised trachea and bronchus tissue explants, we observed a short-circuit current response to forskolin and IBMX (F&I) and inhibition by GlyH-101, consistent with CFTR function. Compared to non-transduced animals, cultured ethmoid sinus epithelia also showed evidence of correction by short-circuit current measurements. Loss of CFTR results in reduced bicarbonate transport and a lower ASL pH. A reduction in ASL pH impairs bacterial killing. Following gene transfer, we observed an increase in nasal and tracheal pH and rescue of bacterial killing. Together, these exciting results demonstrate the first evidence of functional in vivo correction of CFTR by a lentivirus in the CF pig model. These findings support the utility of a lentivirus for CF gene therapy.

Organic and Inorganic Fractions of Diesel Exhaust Particles Produce Changes in Mucin Profile of Mouse Trachea Explants

Diesel exhaust particles (DEP) contain organic and inorganic elements that produce damage to the respiratory epithelium. The aim of this study was to determine the mucus profile of tracheal explants exposed to either crude diesel exhaust particles (DEP) or DEP treated with nitric acid (DEP/NA), with hexane (DEP/HEX), or with methanol (DEP/MET) at concentrations of 50 and 100 μg/ml for 30 and 60 min. Tracheal explants were subjected to morphometric analyses to study acidic (AB+), neutral (PAS+), and mixed (AB+/PAS+) mucus production and vacuolization (V). Incubation with 50 μg/ml crude DEP resulted in a rise in acid mucus production, an increase in vacuolization at 30 min, and reduction in neutral mucus at 30 and 60 min. Tracheas exposed to DEP/MET at 50 μg/ml for 30 or 60 min resulted in a significant decrease in neutral mucus production and an elevation in acid mucus production. DEP/HEX increased vacuolization at both 50 and 100 μg/ml at 30 and 60 min of exposure. Treatment with 50 μg/ml for 30 or 60 min significantly elevated mixed mucus levels. These results suggest that DEP appear to be more toxic when administered in combination with HEX or MET. DEP/MET modified the mucus profile of the epithelium, while DEP/HEX altered mucus extrusion, and these responses might be due to bioavailability of individual elements in DEP fractions.

Diesel exhaust particulates affect cell signaling, mucin profiles, and apoptosis in trachea explants of Balb/C mice.

Particulate matter from diesel exhaust (DEP) has toxic properties and can activate intracellular signaling pathways and induce metabolic changes. This study was conducted to evaluate the activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) and to analyze the mucin profile (acid (AB(+) ), neutral (PAS(+) ), or mixed (AB/PAS(+) ) mucus) and vacuolization (V) of tracheal explants after treatment with 50 or 100 μg/mL DEP for 30 or 60 min. Western blot analyses showed small increases in ERK1/2 and JNK phosphorylation after 30 min of 100 μg/mL DEP treatment compared with the control. An increase in JNK phosphorylation was observed after 60 min of treatment with 50 μg/mL DEP compared with the control. We did not observe any change in the level of ERK1/2 phosphorylation after treatment with 50 μg/mL DEP. Other groups of tracheas were subjected to histological sectioning and stained with periodic acid-Schiff (PAS) reagent and Alcian Blue (AB). The stained tissue sections were then subjected to morphometric analysis. The results obtained were compared using ANOVA. Treatment with 50 μg/mL DEP for 30 min or 60 min showed a significant increase (p < 0.001) in the amount of acid mucus, a reduction in neutral mucus, a significant reduction in mixed mucus, and greater vacuolization. Our results suggest that compounds found in DEPs are able to activate acid mucus production and enhance vacuolization and cell signaling pathways, which can lead to airway diseases.

Effect of Silymarin and Harpagoside on Inflammation Reaction of BEAS-2B Cells, on Ciliary Beat Frequency (CBF) of Trachea Explants and on Mucociliary Clearance (MCC)

Silymarin and harpagoside are derived from drugs which are used for their protective effects against hepatotoxicity and inflammatory processes. Both are now investigated with respect to the respiratory tract. They were able to reduce the release of the inflammatory cytokine RANTES (regulated on activation, normal T cells expressed and secreted) from BEAS-2B cells in a concentration-dependent manner when stimulated by a cytokine mix (10 ng/mL of TNF- α and IFN- γ). This effect was not due to a possible toxic effect (control experiments using LDH release as a marker). Silymarin but not harpagoside was able to increase ciliary beat frequency. Effects were comparable to positive controls (isoprenaline and salbutamol). Silymarin also increases mucociliary clearance. In conclusion, silymarin should be further investigated for its clinical use in distinct respiratory diseases.

Functional imaging of mucociliary phenomena

We present a technique for the investigation of mucociliary phenomena on trachea explants under conditions resembling those in the respiratory tract. Using an enhanced reflection contrast, we detect simultaneously the wave-like modulation of the mucus surface by the underlying ciliary activity and the transport of particles embedded in the mucus layer. Digital recordings taken at a speed of 500 frames per second are analyzed by a set of refined data processing algorithms. The simultaneously extracted data include not only ciliary beat frequency and its surface distribution, but also space-time structure of the mucociliary wave field, wave velocity and mucus transport velocity. Furthermore, we propose the analysis of the space and time evolution of the phase of the mucociliary oscillations to be the most direct way to visualize the coordination of the cilia. In particular, this analysis indicates that the synchronization is restricted to patches with varying directions of wave propagation, but the transport direction is strongly correlated with the mean direction of waves. The capabilities of the technique and of the data-processing algorithms are documented by characteristic data obtained from mammalian and avine tracheae.

Modulation of MUC7 Mucin Expression by Exogenous Factors in Airway Cells In Vitro and In Vivo

The human MUC7 gene encodes a low-molecular-mass mucin that participates in the maintenance of healthy epithelium in the oral cavity, and possibly in respiratory tracts, by promoting the clearance of various bacteria. We examined whether MUC7 gene is expressed in primary normal human tracheobronchial epithelial cells and whether the expression is modulated by exogenous factors. By assessing MUC7 transcripts, we found that the MUC7 gene was induced by culturing the normal human tracheobronchial epithelial cells at the air-liquid interface, in which the cells were well differentiated. When the cells were treated with a panel of cytokines (IL-1beta, IL-4, IL-13, and TNF-alpha), epidermal growth factor, or a bacterial product (Pseudomonas aeruginosa lipopolysaccharide [LPS]), MUC7 transcripts and glycoprotein products were increased 1.7- to 3.2-fold. The effect of LPS on MUC7 gene expression was also studied in the airway tissues of MUC7 gene transgenic mice. In the in vitro cultured trachea and lung explants, the LPS-treated tissues showed over 2-fold increased levels of MUC7 mRNA compared with the untreated specimens. These results were confirmed by in vivo studies using the lungs and tracheas harvested from the transgenic mice irritated by LPS through the tracheal instillation. By immunohistochemistry, MUC7 glycoprotein was localized in tracheal submucosa within the serous cells. Upon LPS stimulation, the overexpressed MUC7 remains confined to the serous glands. In the lungs, MUC7 seems to be expressed within the respiratory epithelium at the level of the bronchioles. Upon stimulation with LPS, it seems to be overexpressed within the same cells and within the stromal tissue.

In vitro Study of Pasteurella multocida Adhesion to Trachea, Lung and Aorta of Rabbits

In vitro experiments were undertaken to study the adhesion and colonization to tracheal mucosa, lung and aorta explants from freshly killed rabbits of two different strains of Pasteurella multocida. Serotype A:3 (capsulated, fimbriae +, haemagglutination –, dermonecrotic toxin –) isolated from a rabbit with rhinitis, and serotype D:1 (non-capsulated, fimbriae +, haemagglutination +, dermonecrotic toxin +) isolated from a dead rabbit with septicaemia, were used. When the explants were observed under the scanning electron microscope, the type D strain was highly adherent to trachea and aorta explants compared to the type A strain. Adhesion to lung explants was best achieved by the type A strain after 45 min incubation, but after 2 h incubation no significant difference was observed between the strains. Our data indicate that the presence of fimbriae and the absence of capsule seem to enhance the adherence of P. multocida type D strain to tracheal tissue. The capsular material of P. multocida type A strain and the toxin of the type D strain seem to influence the adherence to lung tissue in rabbit. Adhesion of strain D to aorta may indicate the expression of receptors on the endothelium to that strain and may also explain the ability of certain strains to cause septicaemia.

Bradykinin and Respiratory Mucous Membranes: Analysis of Bradykinin Binding Site Distribution and Secretory ResponsesIn VitroandIn Vivo

Bradykinin (BK) and lysyl-BK (lys-BK, kallidin) have been proposed as potentially important mediators of rhinorrhea. Possible mechanisms by which BK might contribute to rhinorrhea were investigated by several approaches. (1) The autoradiographic distribution of 125I-BK binding sites in human inferior turbinate nasal mucosa was determined. (2) The effects of BK and lys-BK and antagonists on radiolabeled respiratory glycoconjugate (RGC) release from human nasal mucosa was measured. (3) The secretory effects of BK were studied in cat tracheal mucosa maintained in short-term explant culture, and in ferret trachea maintained in Ussing chambers. (4) The effects of BK on macromolecule secretion in guinea pig nasal mucosa was studied in vivo. Autoradiographic examination of human nasal mucosa revealed that 125I-BK specifically bound to small muscular arteries, venous sinusoids, and submucosal fibers. No specific binding to submucosal glands or goblet cells was noted. Human nasal fragments secreted significantly increased amounts of RGC in response to 10 microM BK (15.0% +/- 1.8 compared with control values; mean +/- standard error of the mean; n = 7; p less than 0.01 by Student's unpaired t test), 10 microM lys-BK (12.2% +/- 3.3; n = 5; p less than 0.05), and 100 microM methacholine (35.7% +/- 2.3; p less than 0.0001). The addition of 1 microM BK, or 1 microM lys-BK, did not induce release. The addition of the BK receptor antagonist des-Arg9-[Leu8]-BK (10 microM) or inhibition of arachidonic acid metabolism with 50 microM nordihydroguaiaretic acid or 65 microM ibuprofen inhibited the prosecretory effect of 10 microM BK.(ABSTRACT TRUNCATED AT 250 WORDS)

Ciliary beating frequency of frog palate and rat trachea explants under continuous perfusion

1. l. Rat trachea and frog palate explants were continuously perfused for 2hr with 199 tissue culture medium. 2. 2. The ciliary beating frequency of the frog palate exhibited fluctuations twice as large as compared to the rat trachea. 3. 3. The rat trachea model should be preferred to the frog palate for long-term studies on ciliary beat frequency.

Regulation of the synthesis of mucin glycoproteins in swine trachea explants.

Swine tracheal epithelium has been cultured as explants in a chemically defined medium for periods of up to 2 wk. The viability of the explants was shown by the preservation of the ultrastructural features of cells in the epithelial layer and by the active incorporation of radioactive glucosamine and sulfate into secreted mucin glycoproteins. The rate of secretion of mucin glycoprotein was about 0.035 mg per cm2 per d. After initial 24 h lag period was shown to be due to the equilibration of intracellular mucin glycoprotein pools with radioactive precursors. The rate of secretion of glycoprotein showed a linear dependence on the area of the explant, and maximal incorporation was observed at 200 microM glucosamine. A higher concentration of 35SO4, 1000 microM, was required for maximal incorporation of the precursor. Insulin at 0.1 to 1 microgram/ml increased the rate of secretion twofold, whereas 0.1 to 100 micrograms/ml of hydrocortisone and 0.1 to 100 micrograms/ml of epinephrine significantly decreased the rate of secretion. Vitamin A had little or no effect of normal trachea explants at low concentrations, and, at higher concentrations, 10(-5) M, it decreased the secretion of mucin glycoproteins. Vitamin A, at a concentration of 10(-9) M, increased the rate of synthesis of glycoprotein at least fourfold in trachea explants from vitamin A-deficient rats. Mucus secretions collected from the surface of swine trachea and from the culture medium of trachea explants were purified. The mucus was solubilized by reduction and carboxymethylation, and the high molecular weight mucin glycoproteins were purified by chromatography on Sepharose CL-6B columns under dissociating conditions in 2 M guanidine HCl. The mucin glycoproteins purified from swine trachea and from the culture medium of trachea explants were virtually indistinguishable. They showed the same properties when examined by gel electrophoresis and immunoprecipitation. The purified glycoproteins contained about 25% protein, and serine, threonine, and proline were the principal amino acids present. More than 80% of the carbohydride chains in both samples were released by treatment with alkaline borohydride. Nearly the same molar ratio of N-acetylgalactosamine, N-acetylglucosamine, galactose, fucose, sulfate, and sialic acid was found in both preparations.

Prostaglandin H synthase-dependent co-oxygenation of (+/-)-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene in hamster trachea and human bronchus explants.

The role of prostaglandin H synthase (PHS) in the metabolism of 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP-7,8-diol) has been examined in short-term explant cultures of hamster and human tracheobronchial tissues. Labeled BP-7,8-diol was incubated with the explants in the presence and absence of the PHS substrate arachidonic acid (20:4) and the PHS inhibitor indomethacin. The addition of 10 microM to 200 microM 20:4 to incubations of hamster trachea with 5 microM BP-7,8-diol caused significant increases in the formation of 7r,8t-dihydroxy-9t,10t-epoxy-7,8,9,10-tetrahydrobenzo[ a]pyrene (anti-BPDE). These increases were not seen when 1 microM or 20 microM BP-7,8-diol was employed. The stimulation of anti-BPDE formation was observed after incubations of from 1 to 48 h. This stimulation was inhibited to the basal level by 20 microM indomethacin, supporting the role of PHS in the response. No effect of 20:4 was seen on the uptake of BP-7,8-diol by the tracheas or on the formation of water-soluble metabolites. Significant increases in covalent binding of BP-7,8-diol metabolites to DNA of the tracheal epithelium were also elicited by the addition of 20:4, however these increases were not well correlated quantitatively with the increases in anti-BPDE formation. H.p.l.c. profiles of deoxynucleoside adducts from basal and 20:4-stimulated incubations were qualitatively identical. Far greater variability of metabolism was seen in human bronchus explants, but 20:4-dependent increases in anti-BPDE formation could be demonstrated in those tissues as well. Inhibition of this stimulation by indomethacin was either absent or incomplete. This variation in the effect of indomethacin was explained by the examination of the products of 20:4 metabolism by the two tissues. Hamster trachea produced almost exclusively PHS metabolites whereas human bronchus yielded predominantly products of lipoxygenases, enzymes insensitive to indomethacin. In conclusion, this study indicates that co-oxygenation of chemical carcinogens can occur in hamster and human tracheobronchial tissues. The concentration-dependence observed with BP-7,8-diol, however, suggests that this pathway is of minor importance in the activation of BP in these tissues.

Quantitative reduction of 2,3,4-triphenyl tetrazolium chloride by hamster trachea organ cultures: effects of Mycoplasma pneumoniae cells and membranes.

The ability of Mycoplasma pneumoniae cells and membranes to affect tetrazolium reduction by hamster trachea organ cultures was evaluated. Uninfected trachea explants reduced 2,3,5-triphenyl tetrazolium chloride (TTC) and nitro-blue tetrazolium when incubated at 37 C in the absence of air. Reduced tetrazolium salts (formazans) were extractable with acetone or ethylene glycol and could be quantitated spectrophotometrically. The optimal assay system involved the use of three or more tracheal rings incubated for 2 h in 0.12% TTC in Tyrode balanced salts supplemented with 1.2% sodium succinate. Formazan was extracted for 5 min with acetone, and the optical density (490 nm) was determined. Trachea explants with metabolic activity reduced or obliterated by freeze-thaw lysis, heat (56 C X 30 min), or cyanide (0.1 M NaCN X 30 min) had negligible ciliary activity and tetrazolium reduction activity (optical density at 490 nm [dry weight]). Tracheas exposed to mycoplasma cells or membranes also showed significantly decreased ciliary activity and tetrazolium reduction; e.g., only 5pc of the ciliary activity and reduction capacity remained after 5 days in culture when infected with M. pneumonia PI 1428 cells. The data indicate that the exposure of ciliated respiratory epithelium to mycoplasma cells or membranes results in diminished oxidative metabolism, and that the ability to reduce TTC to its formazan is correlated with relative ciliary activity.

Influence of oxygen and culture media on maintenance of whole hamster trachea organ cultures and replication of Sendai virus

Effects of various oxygen concentrations and culture media on the maintenance of 4-day-old hamster trachea organ cultures and the yield of Sendai virus were studied. The basic media used were Eagle minimal essential medium, medium 199, and CMRL 1066 supplemented with glutamine and antibiotics and buffered with NaHCO3 or N-2-hydroxyethyl-piperazine-N'-2'-ethanesulfonic acid (HEPES). In addition, each medium was evaluated under a gas phase of 5% CO2 and 95% O2, 5% CO2 and 45% O2 and 50% N2, or 5% CO2 and 95% air. Culturing of explants with CMRL 1066 and medium 199 buffered with HEPES in the presence of 5% CO2 and air proved most efficient; ciliary movement and ciliated surface epithelium were maintained for periods up to 27 days. No significant difference in the rate of replication of Sendai virus was seen in the three different media with the two buffer systems in the three different gaseous phases. The addition of 0.2% bovine serum albumin to the media yielded greater quantities of virus, up to 200-fold increase in titer without producing changes in ciliary function. A distinctive pattern of morphological changes was observed in explants of trachea epithelia inoculated with Sendai virus. These results suggest the practical application in the use of whole hamster trachea explants as a diagnostic aid in the isolation of Sendai virus from laboratory rodents.

Growth and cytopathogenicity of mycoplasma in human and chicken trachea explants

Growth of various mycoplasma species was obtained in human and chicken trachea explants. A period of adaptation to explant conditions was sometimes necessary before good growth occurred. Detailed studies of the growth of two species in human cultures indicated a normal growth curve, but the susceptibility of human cultures varied. Two species, a virulent strain of M. mycoides var. capri and several strains of M. gallisepticum causing disease in fowls, produced cytopathic effects in the explant cultures. The most notable effect in living explants was that ciliary movement ceased; in stained preparations desquamation of epithelial layers was observed and with infections by M. mycoides var. capri there was extensive damage to all tissues including the cartilage.

Organ cultures in evaluation of antiviral drugs

Human embryonic trachea explants were the only organized tissue in which virus strains, causing colds in man, could be grown and in which the effect of antiviral drugs against cold virus strains can perhaps be assessed. Dog trachea explants could be readily infected with influenza viruses and parainfluenza 1 (Sendai) virus both by conventional methods or by virus aerosols. They can provide a suitable organ culture system for evaluation of antiviral drugs, especially against recent influenza A2 strains. Ferret trachea explants can be employed for antiviral drug evaluation against some influenza A and B or Sendai virus strains but variation in sensitivity between trachea explants from different ferrets is to be expected. Respiratory tissue explants from vervet monkeys, pigs, hamsters, rats and mice can provide tools for studies on the specific virus-cell interaction in organized tissue but did not meet the requirements presented as essential for antiviral drug testing in organ cultures.

A novel technique for in situ demonstration of cell viability and cell injury on the respiratory surface of trachea explants. Brief report.

A novel technique for in situ demonstration of cell viability and cell injury on the respiratory surface of trachea explants. Brief report.