Human Conjunctivitis Research Articles

The ability of salbutamol and theophylline to suppress immediate allergic conjunctivitis in the guinea pig.

Topically administered salbutamol was extremely effective in suppressing immediate allergic conjunctivitis in the guinea pig; a dose as low as 0.1% elicited 98% inhibition. Topical pretreatment with 1% propranolol completely blocked the suppressant action of 0.1% salbutamol. This was also the case after systemic propranolol (1 mg/kg SC); the beta-adrenoceptor antagonist itself has no effect on antigen-induced inflammation. The effect of 0.1% salbutamol was unaltered by pretreatment with the specific beta 1-adrenoceptor antagonist betaxolol (1 mg/kg SC). In marked contrast, the suppressant action of 0.1% salbutamol was profoundly inhibited by pretreatment with the selective beta 2-adrenoceptor antagonist ICI-118,551 (0.5 mg/kg SC). The experiments employing beta-adrenoceptor antagonists unequivocally demonstrate that the salbutamol suppression of immediate allergic conjunctivitis in the guinea pig is mediated via the activation of beta 2-adrenoceptors. The methylxanthine phosphodiesterase inhibitor theophylline was active after oral administration, 50 mg/kg eliciting an 80% inhibition. Theophylline was inactive topically at 1% and 5%, but this could be due to the fact that the compound was insoluble at these concentrations. Thus, procedures that elevate cyclic-AMP levels suppress immediate hypersensitivity reactions in the guinea pig conjunctiva. Whether or nor this offers an alternative approach to treat allergic conjunctivitis in humans remains to be determined.

Paederus, sensu lato (Coleoptera: Staphylinidae): natural history and medical importance.

Staphylinids (Coleoptera) are known as predators of Diptera and other arthropods of medical and veterinary importance, but the genus Paederus has achieved greater notoriety. Paederus includes over 600 described species distributed in all temperate and tropical continents. Many species exist in moist habitats, and some have their life cycles attuned to seasonal fluctuations in water level. Temperate-zone species may have a single annual breeding season in the warmer months, but in tropical species timing of the breeding season appears to depend upon rainfall seasonality. Widely distributed species with a broad latitudinal range seem to be multivoltine, with more generations at lower latitudes. Adults of some species are capable of running on water, navigating in response to light. Unlike most staphylinid adults, which avoid daylight, Paederus adults are active in the open in daylight. However, flight seems largely restricted to nights of high temperature. Adults of some species are wingless, and in other species adults show individual variation in wing length. Adults of at least some species are attracted at night to incandescent and fluorescent lights. Eggs are laid singly on a moist substrate and are susceptible to desiccation. There are 2 larval instars. Larvae remain in concealed, moist habitats and are largely predatory. Pupation occurs in earthen cells. Adults, too, are largely predatory but will feed on certain plant materials. Enormous populations of adults have been recorded in some agricultural habitats; in these cases the beetles are beneficial to agriculture owing to their predation on insect pests. However, they are highly susceptible to insecticides. Adults inadvertently come into contact with humans, especially in the tropics and by attraction to light at night. Hemolymph is released when the insects are crushed on human skin (deliberately or by accident) and can be introduced into the eyes. This hemolymph contains a potent contact toxin that causes dermatitis linearis and conjunctivitis in humans. Epidemics of dermatitis linearis are recorded for many tropical and some temperate countries. The epidemics can be mitigated by simple precautions. The dermatitis can be severe, painful, and unsightly, with erythema persisting for months. Conjunctivitis can result in temporary blindness. The toxic effects of Paederus were unknown to Western medicine until this century, but they were known to Chinese medicine 1,200 years earlier. The principal toxin is pederin, the most complex nonproteinaceous insect secretion known. Pederin occurs in all developmental stages of Paederus fuscipes , the Old World species on which most research has been performed. It has been synthesized and, in pure form, is a crystalline amide soluble in alcohol and water. It is a DNA inhibitor and acts at the cellular level by blocking mitosis. Experimentally, it has suppressed cancerous tumors in mice, rats, and plants, has stimulated regeneration of damaged tissues, has healed chronic, necrotic lesions in geriatric patients, and has induced cell fusion in human skin fibroblasts. It is more toxic externally and internally to rabbits, rats, mice, and guinea pigs than to hedgehogs, chickens, frogs, and toads. It is not known to be toxic to insects, is not attractive to insects, and has little effect against bacteria. Its function as a defensive secretion has not been demonstrated.

Toxic cyanobacteria in the Netherlands

In the summer of 1980 waterblooms and scums ofMicrocystis aeruginosa, Oscillatoria agardhii andGloeotrichia echinulata have been collected from 11 locations. Acute toxicity of sonificated algal suspensions was tested by intraperitoneal injection in mice. The results indicate that in 9 out of 10 sample sites lethalM.aeruginosa hepatoxin(s) were present, while in most samples associated bacterial toxin(s) were possibly involved in SDF (Slow Death Factor) intoxication symptoms and death. Two unialgal strains ofM.aeruginosa (RID-2B, isolated from a Dutch storage reservoir, and the Norwegian toxic CYA 57) showed the same toxicity. Suspensions ofO.agardhii were also found to be lethal. Symptoms and mortality are thought to be attributed to at least two toxic factors. One resembling FDF, the other possibly resulting from associated bacteria. Administration ofG.echinulata suspensions did not kill mice but produced symptoms of illness, which were not consistent with those observed withMicrocystis FDF (Fast Death Factor) or SDF. Because there are no documented cases of health impairments due to cyanobacteria in The Netherlands, an inquiry was held in autumn 1980 and 1981 among 280 physicans practising in Rijnmond, into the occurrence of primary or allergic dermatitis and conjunctivitis in humans after swimming in waterblooms of toxicM.aeruginosa in Lake Brielle. In this inquiry only a few cases of skin reactions and conjunctivitis were reported.

Characterization of an influenza A virus from seals

An influenza A virus antigenically similar to A/FPV/Dutch/27 (Hav1Neq1) [H7N7] was isolated from harbor seals ( Phoca vitulina) that had died of acute hemorrhagic pneumonia on Cape Cod Peninsula, beginning in the winter of 1979–1980. High titers of virus were obtained from the lungs and lower titers from the brains of the seals. Although antigenic analyses and characterization of the RNAs show that all of the genes and gene products are closely related to different avian influenza viruses, biologically the virus behaves more like a mammalian strain. The seal virus replicated and produced pneumonia in experimentally infected harbor seals, but the clinical course and pathology were less severe than in the natural infection; the virus also replicated in ferrets, cats, and pigs but produced no disease. In avian species, the seal influenza virus replicated poorly, produced no disease signs, and was not shed in the feces. Although the seal influenza virus can cause conjunctivitis in humans who have known contamination of the eyes from infected animals, serological studies detected no evidence of seroconversion among persons working with infected seals or with the virus. Preliminary studies detected antibodies to this virus in harbor seals on the New England coast but not in harbor seals, gray seals, or fur seals from other areas, suggesting that this virus may be a new introduction to this species. An Hav1Neq1 [H7N7] virus was also isolated from feral ducks in Iceland in 1980, but the two viruses could be distinguished by analysis of their RNAs and host range. The A/Seal/Mass/1/80 influenza virus provides the first evidence suggesting that a strain deriving all of its genes from one or more avian influenza viruses can be associated with severe disease in a mammalian population in nature. Whether this breach of species specificity represents a unique event in influenza evolution remains to be determined, but raises the possibility that human or animal influenza viruses may be derived directly from avian strains.

Human Conjunctivitis Due to the Newcastle-Disease Virus of Fowls

Human Conjunctivitis Due to the Newcastle-Disease Virus of Fowls