Experimentally induced changes in nasal mucous secretory systems and their effect on virus infection in chickens. I. Effect on mucosal mrphology and function.

The domestic chicken was used as an experimental model in which to demonstrate morphological and functional relationships of nasal organ systems, principally of mucous systems. Mucous secretions of olfactory, respiratory, lacrimal, and accessory areas were found to have clear histochemical differences, yet were sufficiently miscible in normal circumstances to form an unbroken, synchronously moving sheet. Changes induced experimentally in host physiology did not all affect the mucous components of given areas in the same way or to the same degree. Mucosal changes were produced by the following methods: Topically administered cocaine 20%, in a single application, temporarily paralyzed the cilia, and the consequently reduced traction apparently held mucus in the acini and effected a temporary lag in mucus excretion. Three successive applications caused acute acinar depletion and ciliary paralysis. Hexylcaine chloride 5% immediately desquamated all intranasal epithelia, damaged the proximal portion of the acini, and induced acinar exhaustion and mucosal inflammation-effects not overcome within 5(1/2) days. Internal dehydration produced progressively viscous mucus, severe acinar gaping with mucus anchored in the acini, a heavy surface sheet, and deceleration or arrest of mucociliary flow. Avitaminosis A induced reduction in the height (about 50%) of all mucosae and acini, especially the inner lining of the maxillary concha, caused an actual 50% reduction in the number of cells per acinus, and retarded the mucociliary flow rate about 50%. Pilocarpine induced initial hypersecretion, later exhaustion, and, still later, slow production of densely staining mucus in the acinar cells; also acinar gaping. Breeding in a germfree environment produced a greatly reduced mucosal depth throughout the nasal fossa, an extraordinary reduction in the number of cells per acinus, relative reduction in the number of acinar neck cells, and concomitant increase in ciliated cells in that region. Exposure to a temperature of -20 degrees C for 1 hr caused blanching of all secretory cells, acinar gaping, and temporary reduction of mucosal depth.

Laryngotracheitis virus in chickens. A model for study of acute nonfatal desquamating rhinitis.

Infectious laryngotracheitis can be produced in chickens as an experimental model of severe nonfatal rhinitis and sinusitis. Inoculated intranasally into unanesthetized baby chicks it remains limited to the nasal fossa, produces acute desquamation of all nasal epithelia, results in functional recovery of the respiratory epithelium, but leaves important residual abnormalities. From the earliest recognizable lesions through 4(1/2) months' convalescence, the principal changes are as follows: 1. Initial lesions, or small syncytia of intranuclear "inclusions", first identifiable in the mucociliated cells of the shallowest portion of the epithelium at about 21 hr postinoculum (the inner surface of the maxillary conchal scroll). 2. Acute sloughing, (about 3 to 7 days), marked by: (a) spread of lesions from cell to cell via multinucleated "giant cells" which progressively slough and desquamate respiratory, olfactory, and sinus epithelia, epithelial neural elements and blood vessels; (b) appearance of numbers of eosinophilic leukocytes along the basement membrane at the sites of lesions just previous to sloughing; intensive infiltration of the submucosa with small lymphocytes after sloughing begins; (c) histochemical change in the intracellular mucus of the cells which comprise the syncytia: this mucus stains with Alcian blue alone when stained with AB-PAS; and (d) all cartilages of the maxillary conchae become flaccid, and the cell nuclei and matrix lose both basophilic and Alcian blue staining properties, effects which recede by about the 8th day. 3. Repair (about 8 to 21 days), marked by rapid initial spread of a sheet of epithelial cells over the infiltrated subrmucosa, appearance of numbers of plasma cells circulating in the tissues, formation of encapsulated secondary nodules, and mucosal adhesions. 4. Convalescence (about 1 to 4(1/2) months when experiments terminated), marked by functional restoration of the mucociliary lining of the nasal fossa. However, at 4(1/2) months eight specimens all show complete metaplasia of the olfactory organ (end nerves, supporting cells, and glands of Bowman) to mucociliated epithelium, all show abnormal formation and alignment of mucous acini, and about 50% have severe persistent sinusitis.

Nasal mites parasitic in nasal and upper skull tissues in the baboon (Papio sp.).

Nasal mites (Rhinophagus sp.) were found within the mucosal and submucosal nasal tissues and bone marrow of the upper skull in two of five adult baboons (Papio sp.).

Dexamethasone suppresses tumor necrosis factor-alpha-induced apoptosis in osteoblasts: possible role for ceramide.

Ceramide has been proposed as a second messenger molecule implicated in a variety of biological processes, including apoptosis. Recently, it has been reported that tumor necrosis factor-alpha (TNF-alpha) activates the release of ceramide and that ceramide acts as a mediator for the TNF-alpha-induced stimulation of the binding affinity of nuclear factor-KB (NF-KB), a ubiquitous transcription factor of particular importance in immune and inflammatory responses. In this study we demonstrate that dexamethasone, which reduces the production of ceramide, significantly inhibits TNF-alpha-induced activation of NF-KB, c-Jun N-terminal kinase, also known as stress-activating protein kinase, caspase-3-like cysteine protease, redistribution of cytochrome c, and apoptosis in MC3T3E1 osteoblasts. Compared with TNF-alpha-induced JNK activation, ceramide elicits a more rapid activation of JNK within 30 min. C2-ceramide activates NF-KB and caspase-3 like protease to the same degree and with kinetics similar to those of TNF-alpha. This study provides evidence that the release of ceramide may be required as a second messenger in TNF-alpha-induced apoptosis. These results also suggest a regulatory role for dexamethasone in TNF-alpha-induced apoptosis via inhibition of ceramide release. Therefore, our in vitro results suggest that therapies targeted at the inhibition of ceramide release may abrogate inflammatory processes in TNF-alpha-related diseases, including rheumatoid arthritis and periodontitis.

The p38 mitogen-activated protein kinase pathway regulates interleukin-6 synthesis in response to tumor necrosis factor in osteoblasts.

The induction of interleukin-6 (IL-6), using a proinflammatory cytokine (tumor necrosis factor-alpha), was studied in a human osteoblast cell line (MG-63) in relation to p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-kappaB transcription factor. When added to MG-63 cells, tumor necrosis factor-alpha (TNF-alpha) had a stimulatory effect on the production of IL-6, and this elevation was significantly reduced by SB203580, a specific p38 MAPK inhibitor. In addition, the stimulation of IL-6 release was also reduced by pyrrolidine dithiocarbamate (PDTC) or NF-kappaB SN50, which has been reported to be a potent NF-kappaB inhibitor. Both the NF-kappaB inhibitors in the presence of SB203580 had a more inhibitory effect on IL-6 release. In this study, TNF-alpha stimulated NF-kappaB binding affinity as well as p38 MAP kinase activation, leading to the release of IL-6. However, the specific inhibitor of p38 MAPK, SB203580, had no effect on TNF-alpha-induced NF-kappaB activation and both NF-kappaB inhibitors failed to reduce the p38 MAPK activation in the TNF-alpha-stimulated osteoblasts. In addition, inhibition of p38 MAPK partially, but significantly, impaired TNF-alpha-regulated release of osteocalcin, an important differentiation marker in osteoblasts. These results strongly suggest that both p38 MAPK and NF-kappaB are required in TNF-alpha-induced IL-6 synthesis and that these two TNF-alpha-activated pathways can be primarily dissociated. Furthermore, p38 MAPK may play a significant role in differentiation in MG-63 cells.

Mucus-stimulating factor in tears.

Mechanisms responsible for regulation of tear film mucus are poorly understood. Humoral factors responsible for stimulation of mucus secretion can be studied in vitro by using the free-swimming urn cell, a normal component of the coelomic fluid of the marine invertebrate Sipunculus nudus. With this system, a tear mucus-stimulating factor was found in normal human tears but was markedly decreased in patients with dry eye syndromes. It is suggested that a mucus-stimulating factor exists in normal human tears and that a decrease in this substance may be instrumental in the pathophysiology of certain dry eye syndromes.

Ecology of respiratory virus transmission: a comparison of three communities in West Bengal.

Respiratory virus transmission in children was studied comparatively in three ecologically different low-income communities in West Bengal: an isolated village, a suburban village, and a crowded urban community. Continued use of contaminated pond water for bathing, irrigation of nasal passages, post-defecation washing of the anus, and washing of food vessels was common to all, as was intense crowding of indoor sleeping quarters during cold and wet seasons. Intensity of infection was highest (26%) in the most crowded urban area, the variety of virus types least in the most isolated village. Sources of drinking water differed but seemed unrelated to virus transmission. Toxigenic diphtheria organisms were found in nonspecific skin lesions in children in each area.

Effect of ionizing radiation on the differentiation of ROS 17/2.8 osteoblasts through free radicals.

Although the acceleration of bone regeneration by radiation has been reported, the mechanisms of action of radiation on bone are unclear. The present results indicate that ionizing radiation-stimulated differentiation could result from the generation of reactive oxygen species during radiation exposure. The free radical release is considered as the most important mechanism of bone effect by radiation treatment. In addition, we report that radiation induced transient activation of c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) activation and the transcription factor, AP-1. The JNK and AP-1 activation is mediated with radiation-released free radicals in ROS 17/2.8 osteoblasts. These results indicate that ionizing radiation at a single dose of up to 5 Gray stimulates differentiation of ROS 17/2.8 osteoblasts via free radial release which may affect JNK/SAPK and AP-1 activities.

Nitric oxide is a regulator of bone remodelling.

Nitric oxide (NO) is known to be implicated in the metabolism of bone, especially as a mediator of cytokine effects on the remodelling of bone tissue. In this study we examine whether NO affects the osteoblast activation or the osteoclast differentiation of primary mouse osteoblast-like and osteosarcoma ROS 17/2.8 cell lines. Primary osteoblast and ROS 17/2.8 cells released NO upon stimulation of interleukin-1 beta, tumour necrosis factor-alpha, and interferon-gamma. Sodium nitroprusside, a donor of nitric oxide, increased the activity of alkaline phosphatase in ROS 17/2.8 cells as well as the number of calcified nodule formations in primary mouse osteoblast-like cells. Sodium nitroprusside also completely inhibited 1 alpha, 25-(OH)2D3-induced osteoclast generation in a high concentration (100 microM). However, a low concentration of sodium nitroprusside (3-30 microM) significantly increased the generation of osteoclasts. These results indicated that NO appears to be an important regulatory molecule in the processes of bone formation and resorption. Hence, NO may be involved in the pathogenesis of bone loss in diseases associated with cytokine activation, such as periodontal disease and rheumatoid arthritis.

Effect of SO2 on nasal secretory cells.

Quantitative histochemical analysis of the secretory cells producing the different types of glycoproteins were examined in the chicken nasal cavity with and without moderate levels of SO2 exposure for 14 days. On the nasal maxillary concha of chickens, the number of acinar gland cells containing glycoproteins was significantly reduced on the 1st, 7th and 14th days of exposure to 11.8 ppm of SO2, but not on the 5th day of exposure. There was no histochemical modification in the intracellular glycoproteins of the acinar cells. The number of goblet cells in the same region increased greatly and showed a change of intracellular glycoproteins from neutral to acid between the 5th and 7th day of exposure.

Effect of mechanical stimulation on mucociliary clearance of chicken sinus.

The hypothesis that homeostatic control mechanisms control mucociliary function in ciliated mucous membranes was induced artificially by means of mechanical stimulation. The edge of right palatine cleft was stimulated mechanically by gentle touching with a dissecting needle, and sinus clearance time was recorded as soon as mechanical stimulation was initiated. Mechanical stimulation caused acceleration of mucociliary flow of the sinus; sinus clearance time was accelerated on the side adjacent to the mechanically stimulated side of the palatine cleft, but not on the opposite side. Therefore, the reflex may be effective only on the stimulated side. We investigated the effect of nerve blockers on mechanical stimulation. Mucociliary clearance in the chicken sinus was not affected by parasympatholytic agents, but was decelerated by the beta-adrenergic blocker. The effect of nerve blockers on the mechanical stimulation showed that parasympatholytic agents blocked mechanical stimulation, while sympatholytic agents did not completely block the response. These data suggest that mucociliary clearance may be regulated by the reflex of parasympathetic and partially sympathetic nerve fibers.

Effect of SO2 exposure on nasal mucociliary clearance in intact chickens.

The time required for mucociliary clearance from the chicken nasal turbinate and from the maxillary sinus was investigated in individual animals by using a newly designed plastic holder for the experimental animals. Determined in this way were: 1) the effect of SO2 exposure on sinus and turbinate clearance time, 2) the effect of the nerve blocking drugs atropine, scopolamine, reserpine, and propranolol on turbinate clearance time, and 3) the effect of these nerve blockers on clearance rates in chickens exposed to SO2. Turbinate mucociliary clearance was measured at 5 intervals per day, during 1 to 7 hr after exposure, for 7 consecutive days. Sinus clearance time was measured twice daily 1 to 4 hr after exposure. Turbinate clearance time in birds exposed to 6 ppm, and sinus clearance time in birds exposed to 40 ppm intermittently for 2 consecutive days both increased strikingly as a direct effect of SO2 exposure. However, continuous exposure to 6 ppm of SO2 during 16 hr per day for 7 consecutive days produced double peaks of increased turbinate clearance time with intervening recovery periods, suggesting an intranasal mucociliary homeostatic response. In individual animals, 26 of 35 animals (75%) exposed to 5 ppm, and 5 of 10 animals (50%) exposed to 20 ppm continuously during 16 hr per day for 7 consecutive days showed the same patterns. Reserpine and propranolol, which are sympatholytic agents, produced decelerated intranasal transport rates. Atropine and scopolamine, which are parasympatholytic agents, did not affect clearance rates. These nerve blockers, however, blocked the biphasic recovery pattern due to SO2 exposure. This blocking effect was statistically significant for atropine and reserpine 1 hr after injection.

Mucociliary transport in chickens infected with Newcastle disease virus and exposed to sulfur dioxide.

Mucociliary transport was studied in the nasal mucous membranes and sinuses of 3-week-old chickens which were either exposed to sulfur dioxide (SO2), infected intranasally with the mesogenic strain of Newcastle disease virus (NDV), or exposed to SO2 after NDV infection. A newly developed apparatus was used to follow intranasal transport rates over time in the same animal, and to follow sinus transport rates over time in a separate group of animals. Intermittent exposure to concentrations of 1.4-66.0 ppm SO2 produced peaks of increased intranasal transport time, with intervening recovery periods. This suggests a homeostatic mechanism. Transport was also decelerated in the sinus when concentrations of SO2 were above 10 ppm. NDV infection produced decelerated intranasal transport rates but did not decelerate sinus rates. Combined NDV and SO2 interacted to produced persistent deceleration of the intransal transport rate. In the sinus, the combination seemed to conteract the decelerating effect of SO2 alone, suggesting a separate mechanism of homeostasis.

Mucous hypersecretion induced in isolated mucociliated epithelial cells by a factor in heated serum.

A factor in the serum of the marine coelomate, Sipunculus nudus, induced by injecting a mixture of a marine bacterial vibrio and a solution of dried cholera toxin, will, after heating to 85 to 90 C, cause intensive continuous hypersecretion of mucus in isolated free-swimming mucociliated cells from another Sipunculus. The factor, released from coleomic cells into the serum, is heat stable to 90 C, withstands several freeze-thawings, is induced only by specific stimuli, is rapidly released into the serum, persists for different time spans depending on the stimulus, and is not present in normal heated sera. It is proposed that in nature this factor is balanced by a heat labile inhibitory factor. Cholera toxin alone is a feeble stimulus. The marine vibrio alone is a powerful stimulus to mucus secretion but lethal for the host. In combination with cholera toxin, the vibrio is nonlethal.

Mucus-stimulating substances in human body fluids assayed in an invertebrate mucous cell system.

An in vitro cell system has been shown to respond differentially to body fluids from normal subjects and from those with disorders of mucus secretion. The urn cell complex of the marine invertebrate Sipunculus nudus responds to mucus-stimulating substances (MSS) in normal human lacrimal fluids and stool filtrates by producing mucus. The process of mucus secretion can be directly observed, and the amount produced can be measured, in a calibrated light microscope. MSS are decreased in lacrimal fluids of patients with dry-eye conditions, while they are periodically increased in filtered stools of patients with acute Shigella dysentery and acute cholera. MSS are remarkably increased isotonic dilutions of sera of rabbits with acute mucoid enteritis, but are absent from sera of normal rabbits. MSS are present in isotonic dilutions of normal human sera which are heated to 85 degrees C for 4 minutes, but are absent from similarly processed sera of immunosuppressed patients. Mean MSS values of heated sera of children with cystic fibrosis are higher than those of controls. The active factor in tears and serum is a large molecule and is heat-stable.

Acute newcastle viral infection of the upper respiratory tract of the chicken. II. The effect of diets deficient in vitamin A on the pathogenesis of the infection.

Keratotic and squamous changes characteristic of vitamin A deficiency were minimal even in chicks which were malnourished and growth stunted and had no vitamin A in their diet. However, when these chicks were infected with Newcastle disease virus (NDV), keratotic changes appeared, most markedly in areas regenerating after infection. In chicks raised on full nutrient diets lacking only vitamin A, keratotic changes appeared in several areas of nasal mucosa but were absent from the mucosa of the inner (under) surface of the maxillary turbinate. Following NDV infection, such changes did appear in the inner lining epithelia. It is suggested that depletion of vitamin A causes regenerating epithelial cells to keratinize. Other effects of combined lack of vitamin A plus NDV infection were exhaustion of lymphoid cells from cranial bone marrow and exhaustion of lymphoid cell systems locally from the nose and paranasal glands.

Lymphocyte depression induced in chickens on diets deficient in vitamin A and other components.

Chickens maintained from time of hatching to age of 30 days on a diet lacking vitamin A, and on 2 diets lacking vitamin A and other nutritional components showed depletion of lymphocyte and plasma cell populations in nasal, paranasal and bursal lymphoepithelial tissues. Effects were significant with all diets but most severe with the most deprived diet. Infection of these birds with Newcastle disease virus showed further depletion of plasma cells, subnormal inflammatory response, keratinization of bursal epithelia and postsloughing metaplasia of nasal mucociliated epithelia. The bursae of infected chickens on the diet lacking only vitamin A were completely devoid of lymphocytes 6 days after Virus inoculation. Infected chickens on the most deprived diet showed atrophy of areas of intranasal epithelia which indicated failure of basal cells to synthesize replacement cells.

Acute Newcastle viral infection of the upper respiratory tract of the chicken. I. A model for the study of environmental factors on upper respiratory tract infection.

Acute Newcastle disease virus infection following intranasal inoculation of chicks with a mesogenic strain of the virus produced a localized infection of the middle turbinate which was histologically demonstrable 18 hours after inoculation. There was destruction of mucous cells of individual acini in the under surface of the middle turbinate, and the infection rapidly spread to ciliated and goblet cells and to neighboring acini. By day 2 there was simultaneous remodeling of the mucosa, continued destruction and inflammatory infiltration and frequent loss of cartilage basophilia. By day 3 polymorphonuclear cells almost disappeared, epithelial mitoses commenced, and lymphocyte infiltration intensified; the plasma cells normally present along the lateral nasal gland ducts were often destroyed, very occasionally the glands themselves were destroyed. By days 5 and 6 inflammation greatly decreased, and by day 8 the mucociliated epithelium was essentially normal. The infection is sequentially comparable to acute mild rhinitis of man.

Ultrastructure of the mucociliary interface in the nasal mucosa of the chicken.

The ultrastructure of the extracellular mucous blanket at the nasal cavities of the chicken was preserved by a method that stabilizes primarily carbohydrate moieties. The cilia were apparently fixed as if "frozen" in the act of beating. The blanket was markedly heterogeneous, with a basic fibrous structure, and it contained membrane remnants. The lumenal surface of the blanket was smooth, but the surface in contact with the cilia penetrated to varying depths between the ciliary shafts. The findings are discussed in terms of the assumptions made by others on the basis of indirect evidence.