Absence Of Direct Contact Research Articles

A prospective assessment of the remote practice of allergy: Comparison of the diagnosis of allergic disease and the recommendations for allergen immunotherapy by board-certified allergists and a laboratory performing in vitro assays

The remote practice of allergy may be defined as diagnosing allergic disease, recommending therapy (including allergen immunotherapy), and providing allergen extract for immunotherapy in the absence of direct contact with the patient.’ In the most common arrangement the referring physician, usually a nonallergist, submits a serum specimen to a laboratory accompanied by a completed form which is provided by the laboratory and contains information from the history and physical examination. The laboratory performs in vitro assays of total and allergen-specific IgE. On the basis of the results of these tests and the data provided on the patient information form, a diagnosis of allergy and specific recommendations for treatment are made by the laboratory. The recommendations to the referring physician include the specific components of an allergen extract for immunotherapy, if this form of treatment has been suggested.

Depression of endothelium-dependent relaxation in aorta from rats with Brugia pahangi lymphatic filariasis.

A role for altered endothelial cell function is emerging in the pathogenesis of disease. We have previously demonstrated that Dirofilaria immitis, the canine heartworm, depresses endothelium-dependent responses and alters the mechanism of relaxation in the in vivo femoral artery of infected dogs. Exposure of rat aorta to the parasite or parasite-conditioned medium selectively depresses endothelium-dependent relaxation. D. immitis is closely related to the major human filarial pathogens. This study was designed to examine the effect of chronic infection with the filarial nematode Brugia pahangi on endothelium-mediated responses of the rat aorta in vitro. We tested the hypothesis that endothelium-dependent responses are depressed in the aorta from rats infected with B. pahangi. Rings of thoracic and abdominal aorta were suspended in muscle baths for measurement of isometric tension. Dose-response relations to norepinephrine, endothelium-dependent dilators (acetylcholine, histamine, and A23187), and nitroglycerin were done. In some experiments, inhibitors of cyclooxygenase (indomethacin and aspirin), guanylate cyclase (methylene blue), and nitric oxide formation (N-nitro-L-arginine methyl ester; L-NOARG) were used. No differences in vascular reactivity were detected in the thoracic aorta. In contrast, endothelium-dependent responses in abdominal aorta of Brugia-infected rats were significantly depressed when compared with control aorta from noninfected rats. Acetylcholine relaxation was further depressed by indomethacin and aspirin. After L-NOARG, acetylcholine relaxation in control abdominal aorta was completely abolished; however, in abdominal aorta of Brugia-infected rats, acetylcholine still caused relaxation. Methylene blue inhibited acetylcholine relaxation in both control and Brugia-infected abdominal aorta; however, relaxation in Brugia-infected aorta was significantly greater than control. This study demonstrates that endothelium-dependent relaxation can be altered by chronic experimental filarial infection in the absence of direct contact between the blood vessel and the parasite. The mechanism of relaxation in the Brugia-infected abdominal aorta appears to be altered when compared with control, suggesting that parasites are capable of modulating vascular reactivity by inducing changes in endothelial cell behavior. The mechanism may involve parasite-induced local inflammation or alterations in endothelial cell metabolism. Understanding how chronic experimental filarial infection alters vascular reactivity may enhance our understanding of the pathogenesis of human filariasis.

Human Neutrophils Activated by Interferon-γ and Tumour Necrosis Factor-α Kill Entamoeba histolytica Trophozoites In Vitro

The interaction between cytokine-activated human neutrophils and Entamoeba histolytica trophozoites was studied as well as the mechanism(s) involved. Treatment of neutrophils with rIFN-gamma alone allowed them to kill 30% of E. histolytica trophozoites; however, rIFN-gamma and rTNF-alpha pretreatments in combination increased neutrophil killing to 70%. In the absence of direct contact between neutrophils and amebae, rIFN-gamma-treated neutrophils were shown to kill 70% of amebae, and rIFN-gamma- and rTNF-alpha-treated neutrophils killed 97% of amebae. Neutrophil enhancement of amebicidal activity following cytokine treatments was correlated with increased neutrophil resistance to amebic contact-dependent killing and was shown to be 73% H2O2 dependent.

Endotoxin-stimulated mononuclear phagocytes secrete soluble factors with bone-resorbing activity.

An in vitro co‐culture system composed of bone marrow‐derived mononuclear phagocytes (obtained from endotoxin‐responsive mice) and 45Ca‐labeled calvaria (obtained from endotoxin‐hyporesponsive mice) was established in order to examine the direct effect of bacterial endotoxin on bone resorption mediated by mononuclear phagocytes. Co‐cultures treated with endotoxin exhibited a significant increase in bone resorption assessed in terms of the %45Ca released. This increase was observed in the absence of direct contact between the mononuclear phagocyte population and bone, indicating that enhanced resorption occurred as a function of soluble factors secreted by mononuclear phagocytes in response to endotoxin. Co‐cultures which contained devitalized 45Ca‐calvaria failed to exhibit an increase in the %45Ca released following endotoxin treatment. Consequently, the soluble factors secreted by endotoxin‐stimulated mononuclear phagocytes appeared to modulate the activity of endogenous bone‐resorbing cells. Two soluble factors with bone‐resorbing activity were distinguished upon subsequent analysis. These results suggest that the interaction between plaque‐associated bacterial endotoxin and mononuclear phagocytes may have important consequences relevant to the resorption of alveolar bone characteristic of chronic periodontal disease.

The conditioning theory of fearacquisition: A critical examination

The conditioning theory of fear-acquisition is outlined and the supporting evidence and arguments presented. It is argued that the theory lacks comprehensiveness and is also inadequate in other respects. Six arguments against acceptance of the theory are advanced. People fail to acquire fears in what are theoretically fear-evoking situations (e.g. air raids). It is difficult to produce conditioned fear reactions in human subjects in the laboratory. The theory rests on the untenable equipotentiality premise. The distribution of human fears is not consistent with the theory. Many phobic patients recount histories inconsistent with the theory. Lastly, fears can be acquired indirectly, contrary to the demands of the conditioning theory. It is suggested that fears can be acquired by three pathways: conditioning, vicarious exposures and by the transmission of information and instruction. Vicarious and informational transmission of fears can take place in the absence of direct contact with the fear stimuli.

In vitro immunity to sheep erythrocytes by fractionated spleen cells: Differentiation within the antibody-forming-cell precursor population

The immunological properties of the rosette-forming cell populations in Fr 2, 2b, and 3 have been compared. The isolated RFC fractions from Fr 2 and 2b respond well in the absence of cell contact with the remaining FIC. In contrast, the RFC population from Fr 3 fails to respond in the absence of direct contact with the FIC population. Bone marrow RFC failed to respond under all test conditions. Stimulation in vitro for 42 hr changes the Fr 3 RFC into one with some of the response characteristics of Fr 2. The thymus cell requirements of the Fr 2 and Fr 3 responses are different. Fr 3 appears to need direct contact with a thymus-derived cell, whereas a trophic phenomenon can be attributed to the thymus cell requirements of Fr 2.

The effects of soil management and fungicides on the development of grey mould (Botrytis cinerea) of strawberries

The incidence of grey mould (Botrytis cinerea Fr.) in Red Gauntlet strawberries growing under a clean cultivation system of soil management was reduced by the use of fungicides captan 0.1 per cent and dichloran 0.2 per cent. Dichloran was phytotoxic, and when applied as a soil drench, reduced yields. With straw mulch and black polyethylene mulch systems of management, there was no reduction in incidence of grey mould through the use of fungicides, but the level of grey mould was lower than with the clean cultivation system. The lower incidence of grey mould under the mulch systems is attributed to the absence of direct contact of the fruit with soil vegetation debris invaded with Botrytis. Polyethylene mulch resulted in earlier cropping than the other management systems. Total yields were the same with polyethylene mulch and clean cultivation, and were lower with straw mulch.

A SURVEY OF THE ENDOPARASITES OF THE RED KANGAROO MEGALEIA RUFA (DESMAREST).

A survey of endoparasites of the Red Kangaroo (Megaleia rufa (Desmarest)) has been carried out in three geographically distinct areas of south-eastern Australia.During a period covering 22 months, 464 kangaroos of different sexes and ages were collected. Alimentary canals and tracheae of all of them and blood and organ smears from 333 were examined for parasites.A list of endoparasites of the Red Kangaroo encountered during the study and of others reported earlier is given. This includes three species of blood protozoa, two species of coccidia (Eimeria spp.), two species of cestode and twenty-one species of nematodes.The numbers of some nematode species are analysed in relation to season, sex of host and age of host as expressed by length of tibia.Two different patterns of age susceptibility of the Red Kangaroo to nematodes are recorded and it is suggested that these may be dependent upon the presence or absence of direct contact of the parasite with host tissue.Distribution of nematodes in the stomach of the Red Kangaroo has been studied. Different species were found to occupy separate niches within the stomach.A statistical test aimed at showing the correlation between severity of infection with some nematodes and condition of host expressed by the ratio: body weight — stomach content/tibia length showed only a very weak negative correlation.Alimentary canals of 100 sheep and thirty-five wild rabbits sampled simultaneously in the same area were found to be infected with only small numbers of worms.No parasites injurious to domestic stock were found in the kangaroos examined.