Chemotaxis of alveolar macrophages and neutrophils in response to microbial products derived from organic dust

Mechanisms of chemotaxis of alveolar macrophages (AMs) and neutrophils (PMNs) in response to microbial products derived from organic dust were studied using the blindwell chemotaxis chamber technique. Seven different known etiological agents causing respiratory symptoms were used for experiments: cell extract and endotoxin from Pantoea agglomerans (synonyms: Erwinia herbicola, Enterobacter agglomerans), cell extracts from Thermoactinomyces vulgaris and Aspergillus fumigatus, protease from Bacillus thermoproteolyticus rokko and two preparations of glucans. These agents were evaluated for their ability to direct attraction of alveolar macrophages and neutrophils and stimulation of alveolar macrophages to release chemotactic factors for other alveolar macrophages and neutrophils. The microbial products were able to attract both alveolar macrophages and neutrophils directly in a dose-dependent manner, and the exposure of cultured alveolar macrophages to most agents stimulated chemotactic activity for for alveolar macrophages and neutrophils. The generation and release of this activity by alveolar macrophages may provide a mechanism for the initiation and amplification of inflammatory reactions in the lung after inhalation of organic dust. Results of these in vitro studies may be relevant to the pathogenesis of alveolitis in organic dust-induced lung diseases.

Chemotaxis of alveolar macrophages and neutrophils in response to microbial products derived from organic dust

The inhalation of organic dust has been implicated to cause a large number of occupational lung diseases. A common event in these diseases is an inflammatory reaction affecting airway and alveolar tissue that is characterized by the recruitment of different types of inflammatory cells. Mechanisms of chemotaxis of alveolar macrophages (AMs) and neutrophils (PMNs) in response to microbial products derived from organic dust were studied. Seven agents known to be etiological agents causing respiratory symptoms (extract and endotoxin of Enterobacter agglomerans, extracts from Thermoactinomyces vulgaris and Aspergillus fumigatus, thermophilic protease, and two preparations of glucans) were used for experiments. These agents were evaluated for their ability to directly attract AMs and PMNs and to stimulate alveolar macrophages to release chemotactic factors for other AMs and PMNs. The microbial products were able to attract both AMs and PMNs directly in a dose-dependent manner and the exposure of cultured AMs to most agents were stimulatory for production of chemotactic activity for AMs and PMNs. The generation and release of this activity by AMs may provide a mechanism for the initiation and amplification of inflammatory reactions in the lung after inhalation of organic dust. Results of these in vitro studies may be relevant to the pathogenesis of alveolitis in organic dust-induced lung diseases.

A sensitive new bioassay for tumor necrosis factor

Tumor necrosis factor is an important cytokine involved in inflammation and assay of this cytokine in biological fluids may be important in the understanding of several disease processes. This report describes an improved TNF bioassay employing a newly isolated subclone of the cell line NCTC-clone 929 as well as a novel fluorescence indicator system for detecting viability of the target cells. The limit of detection for the TNF hypersensitive cell line with this fluorescence viability assay was 68 +/- 2.5 fg/ml, which is approximately 3 x more sensitive than the parental clone and approximately 10 x more sensitive than that reported by Branch et al. (1991) using the neutral red indicator system. The hypersensitivity of the clone gradually declined over a 45-day period and at regular intervals new cells were cultivated from frozen stocks. Two different serum sources, bovine fetal serum and horse serum, and four different serum concentrations (5, 10, 15, 20%) were evaluated to optimize sensitivity. No difference was found between serum sources but sensitivity was significantly reduced if < 15% serum was used.

Superoxide anion production in response to bacterial lipopolysaccharide and fungal spores implicated in organic dust toxic syndrome

High amounts of fungal spores, bacteria, and bacterial endotoxin have been found in dust associated with the poorly characterized syndrome, organic dust toxic syndrome (ODTS). As part of an ongoing investigation to determine the etiopathogenesis for ODTS, this study has focused on activation of guinea pig bronchial alveolar lavage (BAL) cells as evidenced by the production of superoxide anion in response to fungal spores and lipopolysaccharide (LPS). Fungal spores from Aspergillus candidus, Aspergillus terreus, Aspergillus niger, Aspergillus fumigatus, Eurotima amstelodami, Penicillium spinulosum, and Cladosporium cladosporioides were all shown to increase superoxide anion production, each with different potencies. LPS stimulated little superoxide anion production in BAL cells, but when cells were pretreated with LPS prior to stimulation with fungal spores, superoxide anion production was increased over that induced by either spores or LPS alone. These results suggest that the inhalation of LPS together with fungal spores could possibly provoke abnormal lung pathologies.

A comparison of the morphology of denervated with aneurally regenerated soleus muscle of rat

Soleus muscles of rats were denervated, treated with bupivacaine and autografted in order to induce aneural regeneration or only denervated. After 2-70 days, muscles were fixed and embedded in epoxy resin for light and electron microscopy. Regenerating muscles after 2 and 5 days consisted of a necrotic core and a rim of new fibres; the necrotic core had disappeared by day 10. The fibre size (mean cross-sectional area) was 139 microns2 after 10 days; it decreased to 22 microns2 after 70 days. Denervated muscle fibres measured 26 microns2 after 70 days. The sarcomere pattern was regular in 10-day regenerates but later degenerated. There were signs of fibre breakdown; immature regenerating fibres were still found after 70 days. Denervated muscles already contained a few new myotubes at 10 days; at 40 and 70 days fibre loss and regeneration were distinct. The percentage of satellite cells relative to myonuclei (normal 8%) doubled within the first 10 days after necrosis and then fell to less than one fourth of normal. Denervation for 70 days increased threefold the percentage of satellite cells in some muscles and in others caused a decrease to half of normal. The number of fibre cross-sections in regenerated muscles was about 3000 after 10-70 days; this was roughly the same number as in normal soleus muscles. The true number of fibres, however, may have been smaller because regenerated fibres tend to branch. It is concluded that aneurally regenerating muscle fibres reach a high degree of structural differentiation, but then atrophy, degenerate and vanish; they are replaced by new fibres, which do not reach the size of the first fibres, presumably because the satellite cell pool without innervation eventually becomes exhausted. The slow and non-synchronized breakdown of denervated soleus muscle fibres induces proliferation of satellite cells as in necrotized muscles; those muscles which had fewer satellite cells than normal after 70 days might already be showing exhaustion.

Contractile properties of aneurally regenerated compared with denervated muscles of rat

The time course of aneural regeneration in slow-twitch soleus muscles of young adult rats was studied and compared with the changes following denervation in soleus and fast extensor digitorum longus muscles. Regeneration was induced by auto-grafting after treatment with bupivacaine; isometric contractions were recorded from 5 to 70 days later. Force was detected at 5 days; at 12 days force was maximal (at least 20% of original) and thereafter fell exponentially. Force varied normally with total fibre area, except at 5 and 71 days when force generating capacity was low. Contraction and relaxation in the twitch were longer than normal (maximally at 5 days), and were closer to denervated soleus than EDL; in contrast, the maximal rate of rise of force was as high as that of denervated EDL and much higher than in denervated soleus. It is suggested that the muscle was fundamentally fast contracting, but the twitches were probably slow because of greater than normal activation following a single stimulus--a hypothesis supported by twitch:tetanus ratios that were higher than in denervated muscles. Tetanic force was much more sensitive than normal to changes of muscle length from optimum, despite the fact that the lengths of regenerated muscles were similar to those of contralateral muscles. The properties of denervated soleus gradually approached those of regenerated soleus, probably because of replacement of original fibres by regenerated ones.

A faster twitch contraction of soleus in the spontaneously hypertensive rat is partly due to changed fibre type composition

Contractile properties and fibre type composition of slow-twitch soleus muscles from spontaneously hypertensive rats (SHR) were compared with those from a control normotensive strain (Wistar-Kyoto, WKY). Male rats aged around 100 days were used, and muscle tension was recorded isometrically in vitro. Tetanic tension was reduced by about 15% in SHR; this decrease was highly significant when tension was expressed relative to muscle cross-sectional area. Twitch contraction and relaxation were 12-15% faster in SHR. There were no differences in the rate of rise of tension of either tetani or twitches, but the relaxation of tetanic tension was 17% faster in SHR. Twitch:tetanus ratios were 20% smaller in SHR. Histochemistry showed that SHR muscles had a threefold higher proportion of fast type II fibres compared to WKY. There were no significant changes in the contractile properties of the fast-twitch extensor digitorum longus (EDL) muscles of SHR compared with WKY. Whilst the higher proportion of type II fibres could account for some of the contractile changes in SHR soleus muscles, the lack of any difference in the rate of rise of twitch and tetanic tension is not consistent. The faster rate of relaxation of both twitch and tetanus in SHR suggests that a higher rate of removal of calcium, either from the myofilaments or from the cytoplasm, may be an important factor in causing the changes in SHR soleus. The faster relaxation may be compared with a similar change reported in SHR cardiac myocytes.

Oxidative susceptibility of low density lipoprotein subfractions is related to their ubiquinol-10 and alpha-tocopherol content

The conjugated polyene fatty acid parinaric acid (PnA) undergoes a stoichiometric loss in fluorescence upon oxidation and can be used to directly monitor peroxidative stress within lipid environments. We evaluated the course of potentially atherogenic oxidative changes in low density lipoproteins (LDL) by monitoring the oxidation of PnA following its incorporation into buoyant (p = 1.026-1.032 g/ml) and dense (p = 1.040-1.054 g/ml) LDL subfractions. Copper-induced oxidation of LDL-associated PnA exhibited an initial lag phase followed by an increased rate of loss until depletion. Increased PnA oxidation occurred immediately after the antioxidants ubiquinol-10 and alpha-tocopherol were consumed but before there were marked elevations in conjugated dienes. Despite differences in sensitivity to early oxidation events, PnA oxidation and conjugated diene lag times were correlated (r = 0.582; P = 0.03), and both indicated a greater susceptibility of dense than buoyant LDL in accordance with previous reports. The greater susceptibility of PnA in dense LDL was attributed to reduced levels of ubiquinol-10 and alpha-tocopherol, which were approximately 50% lower than in buoyant LDL (mol of antioxidant/mol of LDL) and together accounted for 80% of the variation in PnA oxidation lag times. These results suggest that PnA is a useful probe of LDL oxidative susceptibility and may be superior to conjugated dienes for monitoring the initial stages of LDL lipid peroxidation. Differences in oxidative susceptibility among LDL density subfractions are detected by the PnA assay and are due in large part to differences in their antioxidant content.

The role of social support in compliance and other health behaviors for African Americans with chronic illnesses

Social support plays a positive role in compliance and other health behaviors. The purpose of this study was to investigate the role of social support in compliance and other health behaviors for patients with sickle cell disease and diabetes. Subjects consisted of 49 patients with sickle cell disease and 78 patients with diabetes attending outpatient clinics at an urban hospital. Subjects were given questionnaires which assessed their appointment-keeping behavior, adherence to health activities, and social support. The results indicated that social support was significantly associated with appointment-keeping behavior and adherence to health activities in both the sickle cell and the diabetic sample. Implications of the study findings for improving compliance by increasing social support are discussed.

Complex iliac arterial trauma: autologous or prosthetic vascular repair?

The methods for vascular reconstruction of iliac arterial trauma can be a challenging problem. Primary arterial repair is usually possible, but an extensive injury may require interposition grafting or extra-anatomic bypass. Some investigators have advocated prosthetic grafting as a reasonable method of repair for complex iliac arterial injuries. We challenge this concept and describe our experience with the exclusive use of autogenous vascular repair during involvement with 87 consecutive patients surviving iliac arterial trauma.

Differences between contractions in vitro of slow and fast rat skeletal muscle persist after random reinnervation

1. The medial popliteal nerve was sectioned in adult rats, and reinnervation was permitted after nerve reunion. Reinnervation was observed in soleus (slow twitch) and plantaris (fast twitch) muscles for periods of 4-21 months after the initial operation. 2. In the reinnervated muscles, isometric twitch time to peak (contraction time) and time to half-relaxation were longer in soleus than plantaris in every muscle examined. 3. Some of the muscles were stained for actomyosin ATPase activity. The proportion of type I fibres (presumed slow) was at least twice as high in soleus compared with plantaris muscles. The proportion in the latter was similar to that predicted from random reinnervation. 4. The effects of differing proportions of fast and slow fibres on the twitch contraction and half-relaxation times were modelled, and the experimental twitch data were found to be compatible with the proportions of fibre types in individual muscles. 5. It is speculated that the mechanism accounting for the higher proportion of slow fibres in soleus muscle probably does not involve selective reinnervation. It is suggested that fast motoneurones may be transformed to slow by a trophic chemical released by slow muscle fibres; such a process would be more extensive in predominantly slow twitch soleus than a fast muscle, and the resulting decrease in the proportion of fast motoneurones would account for the less extensive conversion in soleus.

Investigation of an outbreak of "humidifier fever" in a print shop

An outbreak of "humidifier fever" affected 16 (57%) of 28 workers in a print shop. The most common symptoms were myalgia, chills or subjective fever, and cough. Illness began 5-13 hours after entering the workplace, and lasted 2-24 hours. A humidifier in use the day of the outbreak was found to be contaminated with fungi, amebae, and Gram-negative bacteria. The risk of illness was highest for those who had been on the job 3 months before the outbreak, a time when the humidifier was in constant use. Serologic studies of print shop workers showed positive reactions to extracts of organisms isolated from the humidifier, but could neither distinguish ill from well workers, nor identify causative organisms. The presence of endotoxin-producing bacteria and the clinical syndrome are consistent with an organic dust toxic syndrome. Previous exposure appeared to be the major risk factor for illness.

Inhibitory action of tetrandrine on macrophage production of interleukin-1 (IL-1)-like activity and thymocyte proliferation

Tetrandrine is a bisbenzylisoquinoline alkaloid which has been shown to exhibit antifibrotic activity against silicosis. Tetrandrine is characterized by its strong binding to alveolar macrophages and inhibition of particle-induced respiratory burst activity in these phagocytes. In contrast, tubocurine and tubocurarine are structurally similar to tetrandrine but exhibit little effect on fibrosis or activation of alveolar macrophages. The objective of the present study was to test the effect of tetrandrine on macrophage production of monokines in response to occupational dusts, and to determine tetrandrine's effect on monokine-medicated cell growth using a mouse thymocyte proliferation assay and lipopolysaccharide (LPS) as a positive control. Stimulation of alveolar macrophages by respirable silica dust resulted in a release of monokines which caused a fourfold increase in thymocyte proliferation. Coal dust, on the other hand, had no effect on macrophage production of this cytokine. Tetrandrine was found to exhibit a dose-dependent inhibition of monokine release from both silica and LPS-stimulated alveolar macrophages. In experiments where thymocytes were directly treated with tetrandrine, a dose-dependent inhibition of thymocyte proliferation was noted with both interleukin-1-(IL-1) specific and nonspecific mitogenic (concanavalin A) actions. In contrast to the inhibitory potency of tetrandrine, tubocurarine was found to have no effect on either the production of monokines by LPS-stimulated alveolar macrophages or IL-1-mediated thymocyte proliferation. These results provide a correlation between the antifibrotic effect of tetrandrine and inhibition of macrophage activation.

Hormonal responses to removal of a breeding male in the cooperatively breeding white-browed sparrow weaver, Plocepasser mahali

The white-browed sparrow weaver (Plocepasser mahali) is a cooperatively breeding Ploceid finch that lives in groups of up to 11 individuals. Each group consists of a dominant breeding male and female and a varying number of nonreproductive birds that help feed young and defend the group territory. Experimental removal of the dominant male resulted in attempts by other males to take over the group. Removal of a subordinate, nonbreeding male, as a control, resulted in no change of status among group members. During takeover, there was a transitory increase in plasma levels of luteinizing hormone in the new dominant male, but no change in testosterone levels. As reported in previous investigations, dominant males tended to have higher levels of testosterone than females or subordinate males, but this was not related to the heightened aggression of the takeover. Plasma levels of luteinizing hormone, testosterone, and corticosterone did not differ between the other status groups. The possibility that luteinizing hormone, or a hitherto unidentified androgen, may regulate aggression in the white-browed sparrow weaver is discussed.

Novel thiazolidine-2,4-diones as potent euglycemic agents

A new series of thiazolidine-2,4-diones was obtained by replacing the ether function of englitazone with various functional groups, i.e., a ketone, alcohol, or olefin moiety. These compounds lower blood glucose levels in the genetically obese and insulin-resistant ob/ob mouse. Appending an oxazole-based group at the terminus of the chain provided highly potent compounds.

Morphology of long-term denervated rat soleus muscle and the effect of chronic electrical stimulation

1. Rat soleus muscles were denervated for 6-10 months; some of these were chronically stimulated for the last 3-8 weeks before recording. The muscles were fixed at physiological lengths and embedded in epoxy resin. 2. Sections for light microscopy were stained with p-phenylenediamine. Denervation reduced the mean cross-sectional area of fibres to 3% of controls (peak at 20 microns2). The cross-sectional areas of the stimulated fibres had a peak at 70 microns 2. In light micrographs of denervated muscles, the total number of fibres appeared to be reduced; however not all fibres could be identified (see paragraph (3)). 3. In the electron microscope, many fibres showed disarrayed myofilaments. Few fibres had more or less normal cross-striations. Muscle fibres as small as 1 micron in diameter were seen. The smallest fibres did not contain myofilaments. Some unequivocally necrotic fibres were seen. 4. Most stimulated denervated fibres showed an almost normal sarcomere pattern. Scattered throughout the muscle were single fibres as small as 2 microns in diameter, but these were well organized and could be recognized in the light microscope. Few fibres were necrotic. Often fibres were serially arranged. Satellite cells were prominent. 5. It is concluded that in long-term denervated rat soleus the original fibres are lost and those seen are the result of repeated cycles of regeneration and necrosis. Stimulation maintains the sarcomeres and probably prevents secondary degeneration and necrosis.

Effects of chronic electrical stimulation on contractile properties of long-term denervated rat skeletal muscle

1. The contractile properties of fast-twitch (extensor digitorum longus or EDL) and slow-twitch (soleus) muscles in the rat were followed for periods of between 4 and 10 months after denervation. The effects of chronic electrical stimulation during the last 3-8 weeks of denervation were investigated. 2. The fall in tetanic tension that follows axotomy ended after about 4 months' denervation. The equilibrium tension was about 0.75% of control tension in EDL and 0.2-0.3% in soleus. 3. The low tension in soleus was due partly to the small diameter of the muscle fibres (atrophy) and partly to their necrosis that resulted in an 8-fold fall in specific tension (the force per unit cross-sectional area). Similar but less extreme changes occurred in EDL. 4. It is speculated that the final level of tension reached by unstimulated denervated muscles is an equilibrium between decrease in force due to atrophy and necrosis and increase due to regeneration. Differences between the final tension levels in soleus and EDL cannot be accounted for quantitatively by known differences in atrophy alone. Therefore, the rate of necrosis in soleus and of regeneration in EDL may be higher. 5. Chronic stimulation of long-term denervated muscle increased force generation by about 7-fold in EDL and between 20 and 55 times in soleus. The final tension reached was between 4 and 5% of normal in both muscles. Specific tension of fibres was almost completely restored by stimulation and the number of fibres was normal. The failure to recover full tension was largely due to failure to reverse denervation atrophy completely. 6. Twitch contraction and relaxation times were identical in denervated-stimulated soleus and EDL. There was no evidence for dependence on duration of stimulation or tension of the muscle. The normalized maximum rate of rise of tetanic tension remained higher in EDL than soleus.

Histamine and endotoxin contamination of hay and respirable hay dust

Three distinct samples collected from a barn in which an outbreak of respiratory problems occurred were examined for possible etiologic agents. No causal relationship could be established from the results of this study; however histamine concentrations as high as 0.5 ng/mg for bulk hay (in the absence of measurable creatinine levels) along with 6138.3 endotoxin units/mg of hay were present in the samples. Both endotoxin and histamine could be recovered from respirable hay dust. The authenticity of the histamine found in the hay was evaluated with high-performance liquid chromatography and radioimmunoassay. Histamine release caused by hay extracts was evaluated with the use of leukocytes from the farmer and a referent. Histamine is known to modulate the immune system, but the role of occupational or environmental exposure to histamine in respiratory disease is unknown.

A comparison of fibrillation in denervated skeletal muscle of the anaesthetized rat and guinea-pig

We have used intracellular recording in vivo to study fibrillation (spontaneous repetitive membrane activity) in extensor digitorum longus (fast twitch) and soleus (slow twitch) muscles of the anaesthetized rat and guinea-pig denervated for periods of about 10 to 60 days. The proportion of fibres fibrillating in the guinea-pig soleus was greater than 50% in most animals up to the longest period of denervation (65 days). Fibrillation was rarely found in rat soleus after three weeks of denervation. Its incidence in the extensor digitorum longus muscles of both species was intermediate. The mean frequency of fibrillation was higher in guinea-pig extensor digitorum longus (16 Hz) and soleus (8 Hz) than in the rat extensor digitorum longus (3 Hz) and soleus (2 Hz). The resting membrane potentials of the denervated muscles were less than normal and correlated inversely with the frequency of fibrillation but not with the incidence of fibrillation: in rat soleus, many fewer fibers were fibrillating at a given membrane potential than in the other three muscles. The incidence of fibrillation was compared with previously reported tensions of the four denervated muscles and was found to have the same rank order. We suggest that fibrillation may reduce atrophy (and hence tension loss) of denervated muscle, which may have implications for artificial stimulation. Fibrillation frequency was directly related to changes in twitch speed of the four muscles after denervation.

Cytotoxic and immunostimulatory effects of Bacteroides cell products

The etiologic role of Bacteroides in both periodontal and periapical infections has been well documented, with current interest focusing on the specific pathogenic mechanisms involved. The effects of cell fractions derived from Bacteroides gingivalis (BG), Bacteroides intermedius (BI), and Bacteroides asaccharolyticus (BA) have been studied in vitro through: an assessment of the direct cytotoxic effects on human gingival fibroblasts using a tetrazolium dye reduction assay, an evaluation of murine lymphocyte stimulation and interleukin-1 release, and the induction of human lymphocyte-mediated cytotoxicity. Both BG and BI stimulated interleukin-1 release (P less than 0.001), while BA, a nonoral organism, was not significantly active in this respect. Only BG sonicates were able to induce lymphocyte-mediated cytotoxicity (P less than 0.005). All three Bacteroides species demonstrated direct cytotoxic effects on cultured gingival fibroblasts, and these effects were related to the relative protein content and endotoxin activity of the sonicate preparations for each organism. These data show that BG and BI possess factors which may enhance their virulence through activities not shared with BA.

Observations of the use of o-phthalaldehyde condensation for the measurement of histamine

The in vitro study of mast cell degranulation utilises the measurement of histamine as a quantitative marker of this process. Histamine is most commonly assayed, following organic extraction, by condensing it with o-phthalaldehyde (OPT) and thereby obtaining a highly fluorescent adduct. A number of variables that might affect the performance of this assay, including assay conditions, stability and purity, were evaluated during the course of developing this assay for use in our laboratory. We observed the stability of OPT-histamine and found it to be very stable at 0 and 25 degrees C, following acidification. Derivatisation conditions and the purity of the leukocyte histamine extract were also assessed, and indicated that derivatisation at low temperatures slows down decay, providing a greater over-all fluorescence intensity. Extraction procedures are necessary, prior to condensation with OPT, to eliminate both positive and negative interfering substances from leukocyte preparations.

High-performance liquid chromatographic method for the evaluation of possible interferences in basophil-histamine release measurements

Basophil activation studies commonly rely on the measurement of histamine following extraction and condensation to o-phthalaldehyde (OPT) as a quantitative measurement of degranulation. Specificity has long been recognized as a problem with this method. We have described a new high-performance liquid chromatographic method that allows for both a qualitative and a quantitative check of the purity of the OPT-histamine adduct. This method was sensitive (limit of detection = 2.55 pmol) and linear over a wide range (5 to 1000 ng/ml).