Mechanism of slowing of mucociliary transport induced by SO2 exposure.

Responses of nasal mucociliary transport mechanisms to exposure to 6 ppm SO2 were studied in chickens in vivo. This model takes advantage of the natural cleft palate which exposes the mucociliated base of the nasal septum. Exposure to 6 ppm SO2 decreased the mucociliary transport rate along the base of the nasal septum. The minimum force required to move an iron particle along this area of mucous membrane by use of a magnetic field in vivo increased significantly after SO2 exposure, while the minimum force required to move an iron particle on a pool of mucus collected from the same chicken and tested in vitro showed no change after SO2 exposure. The elastic recoil distance of mucus was measured both in vivo and in vitro. The in vivo recoil distance decreased significantly after SO2 exposure, while SO2 exposure did not change recoil distance in vitro. It is proposed that exposure of chickens to SO2 results in the formation of multiple points of adhesion of strands of mucus between the acinar gland cells and the emergent extracellular mucus or adhesion of a mucous blanket to the cilia, causing mucociliary transport to be retarded or static.

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.

The carpal tunnel syndrome and amyloidosis. A clinical and histological study.

Twenty-six non-randomized patients with carpal tunnel syndrome are presented. It is documented that three out of four patients may be diagnosed pre-operatively by five or more clinical parameters. All patients were screened for amyloidosis in biopsies from the carpal tunnel. One patient presented amyloid deposits in the transversal carpal ligament. The importance of macro- and microscopic findings in the carpal tunnel inclusive local amyloidosis for the pathogenesis of the carpal tunnel is discussed. It is concluded that provided systemic amyloidosis is not suspected, screening for amyloidosis may have diagnostic interest, however without therapeutic consequences and therefore unnecessary.

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

The hypothesis that homeostatic control mechanisms control mucociliary function in ciliated mucous membrane was tested. Nasal mucociliary transport rates were recorded in chickens in vivo at successive intervals during exposure to SO2 or after inoculation with Newcastle disease virus (NDV), or both. Either agent alone caused deceleration of the turbinate clearance. However, when SO2 exposure was limited to one nasal fossa and turbinate mucociliary rates were determined in the unexposed and infected side, the two acted antagonistically and yielded approximately normal rates. Exposure of the nasal mucosae to SO2 caused decreased rates of sinus clearance, while NDV infection of nasal membranes induced increased rates of sinus clearance. Exposure of nasal mucosae to both agents acted antagonistically to effect rates of sinus clearance in normal ranges. These data support the idea of homeostasis.

Differences in mucus-stimulating serum fractions of cystic fibrosis patients and controls.

In nature, the urn cell complexes which swim in the coelomic fluid of the marine invertebrate, Sipunculus nudus, produce "tails" of mucus in response to bacterial pathogens. Since they produce measurable tails of mucus in vitro, suspensions of urn cell complexes provide a bioassay for mucus-stimulating substances (MSS) in biological fluids, including several human body fluids. Heat-activated seawater dilutions of human serum contain MSS. Serum from 87 cystic fibrosis (CF) homozygotes, 60 obligate heterozygotes, and 45 controls were fractionated on a Sephadex G-200 gel filtration column. After subsequent heating for 4 min at 85 degrees C, the fractions of all normal sera showed two characteristic peaks of MSS activity. The pattern differed in heated serum fractions of CF patients, in that the second peak was lacking in 59% of individual tests. The pattern was intermediate in heterozygote sera. Of the 36 CF serum fractions which did have two peaks of activity, 89% had the predominant activity in peak 1. The frequency of single peaks of activity increased with patient age, from 33% in those under 10 years to 75% in those over 16. The molecular weight of peak 1 is about 75,000 daltons, of peak 2 about 30,000. One may speculate that the frequent lack of peak 2 serum components may be associated with the inability of most CF patients to produce normal mucus following respiratory infection.

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.

Mucus secretion-stimulating activity in human lymphoblastoid cells.

Two fractions isolated from cultured lymphoblastoid cells stimulated mucus secretion from the urn cell complex of the marine invertebrate Sipunculus nudus. The activity detected in the nuclear fraction was trypsin-sensitive, and it increased in response to specific nucleotides.

In vitro macrophage manifestation of cortisone-induced decrease in resistance to mouse hepatitis virus.

Genetically resistant G3H mice routinely yielded macrophages that were resistant when grown in 90% horse serum. These mice also routinely yielded macrophages that were susceptible to the same virus, MHV (PRI), in vitro after the mice had been treated with three intraperitoneal doses, of hydrocortisone. Dexamethasone and prednisolone when similarly administered also increased the susceptibility of C3H macrophages taken from the treated animal, but progesterone and testosterone did not. In addition, spleen cells from mice treated with cortisone made the resistant C3H macrophages 100 times more susceptible in vitro. Increased in vitro susceptibility induced in this way by hydrocortisone was reversed by exposure to supernatant fluid removed from cultures of concanavalin A-treated spleen cells.

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.

Quantitative histological changes produced in the tracheal mucosa of young chickens by the inhalation of sulfur dioxide in low concentrations.

Chickens were exposed to SO2 in relatively low concentrations (3.4 to 18.5 parts per million (ppm)) for 1 to 14 days. A portion of their tracheas was embedded in water-soluble methacrylate, cut at 2 micrometer and stained with hematoxylin and eosin, Wright's stain, methyl green-pyronin, Alcian blue - periodic and Schiff, and for acid phosphatase. An increase was found in (a) the mucosa to wall ratio; (b) the number of mucosal cells in mitosis; (c) the number of macrophages, lymphocytes, plasma cells, and neutrophils in the epithelium and lamina propria; and (d) the number of these infiltrating cells which contained acid phosphatase. The number of mucus- and seromucus- secreting cells and vasoamine-containing cells were sometimes increased, but not consistently. The percentage of cells containing sialidase-sensitive sialomucins was elevated, and percentage of cells containing neutral mucins was reduced. These changes were only partly related to the SO2 concentration and the duration of SO2 exposure, in that increasing amounts of SO2 did not always cause increasing changes in the mucin composition. Evidently, the altered mucins sometimes protected against further mucin modification.

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.

Blocking of in vitro and in vivo susceptibility to mouse hepatitis virus.

By pretreatment with concanavalin A (Con A) both in vivo and in vitro genetically susceptible mice and their cultured macrophages have been converted to animals and cells which are phenotypically resistant to mouse hepatitus virus (MHV). Con A at 1.0 mg/mouse decreased the mortality from 100% to less than 40% by inducing a prominent inflammatory response, increasing the number of macrophages in the virus inoculation site, and producing a population of macrophages not uniformly susceptible to the virus. In addition, mediators derived from Con A-treated spleen cells conferred resistance to normally susceptible syngeneic macrophages to 100 TCID50 of MHV.