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Biomedical subjects

R O'Hehir

Publications and source records attributed to R O'Hehir.

9 recordsLinked to original sources
PubMed2001

A rapid and efficient two-step gel electrophoresis method for the purification of major rye grass pollen allergens.

Purified proteins are mandatory for molecular, immunological and cellular studies. However, purification of proteins from complex mixtures requires specialised chromatography methods (i.e., gel filtration, ion exchange, etc.) using fast protein liquid chromatography (FPLC) or high-performance liquid chromatography (HPLC) systems. Such systems are expensive and certain proteins require two or more different steps for sufficient purity and generally result in low recovery. The aim of this study was to develop a rapid, inexpensive and efficient gel-electrophoresis-based protein purification method using basic and readily available laboratory equipment. We have used crude rye grass pollen extract to purify the major allergens Lol p 1 and Lol p 5 as the model protein candidates. Total proteins were resolved on large primary gel and Coomassie Brilliant Blue (CBB)-stained Lol p 1/5 allergens were excised and purified on a secondary "mini"-gel. Purified proteins were extracted from unstained separating gels and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot analyses. Silver-stained SDS-PAGE gels resolved pure proteins (i.e., 875 microg of Lol p 1 recovered from a 8 mg crude starting material) while immunoblot analysis confirmed immunological reactivity of the purified proteins. Such a purification method is rapid, inexpensive, and efficient in generating proteins of sufficient purity for use in monoclonal antibody (mAb) production, protein sequencing and general molecular, immunological, and cellular studies.

Allergens↗
PubMed1998

Immunotherapy of allergy: anergy, deletion, and immune deviation.

Decreased allergen-specific T cell proliferation and dysregulated cytokine synthesis accompany allergen immunotherapy, consistent with mechanisms of anergy and immune deviation. Recent studies emphasise the pivotal role of decreased T cell IL-4:IFN-gamma ratios. A landmark clinical trial of T cell epitope peptides for venom-immunotherapy shows efficacy and safety; murine models suggest intramolecular epitope-suppression inhibits responses to the whole allergen.

Animals↗
PubMed1997

Stinging insect allergies. Assessing and managing.

BACKGROUND: Mortality secondary to insect sting anaphylaxis, though uncommon in this country, is a genuine risk to patients with venom hypersensitivity. A number of non specific and specific preventive measures are available to minimise this risk. They include proper patient counselling regarding sting avoidance and the use of self injectable adrenaline, as well as venom specific immunotherapy. OBJECTIVE: This article attempts to review the spectrum of insect sting reactions, their appropriate assessment and subsequent management. Anaphylaxis is particularly emphasised with regard to first aid treatment and subsequent prevention. DISCUSSION: The most common causes of insect stings in Australia are bees and wasps. Insect sting reactions cover a spectrum of responses, from normal to anaphylactic. Immunotherapy is indicated in those patients who experience anaphylactic responses. The presence of venom specific IgE must be demonstrated before commencing immunotherapy. Venom sensitive patients should be educated in anaphylaxis first aid with adrenaline self injectable syringes.

Adrenergic Agonists↗
PubMed1989

Clonal analysis of the cellular immune response to the house dust mite Dermatophagoides farinae.

A panel of human CD4+ T cell clones specific for the house dust mite was isolated from an atopic individual with perennial rhinitis. Soluble antigen specificity was defined using proliferation assays and subsequently the antigenic determinants recognized by some of these clones were mapped using nitrocellulose immunoblots of fractionated Dermatophagoides spp. Both cross-reactive and species-specific T cell clones were identified and in some instances their specificity could be mapped to the serologically defined Der f I, Der p I and Der f II allergens. In comparison, the serum antibody response showed additional specificity for Der f III. The antigen recognition by six of these clones was found to be restricted by HLA-DR gene products.

Allergens↗
PubMed1988

Comparison of the effects of nebulized terbutaline with intravenous enprofylline in patients with acute asthma.

We compared the bronchodilating effects of intravenously administered enprofylline (2 mg/kg) with nebulized terbutaline (10 mg) in patients presenting to hospital with acute asthma in a multicenter double-blind parallel study. One hundred twenty three patients were randomized into the study, and 69 of these fulfilled the inclusion criteria and a retrospective time to study entry criterion; 34 received enprofylline and 35 received terbutaline. There was no significant difference in maximum increase in forced expired volume in 1 second (FEV1) between the enprofylline group (0.24 +/- 0.33 L) and the terbutaline group (0.25 +/- 0.28 L) (p greater than 0.05), nor for the increase in FEV1 over the 1-hour study period. Tremor was reported more in the group receiving terbutaline, and nausea was reported more in the group receiving enprofylline. Two patients experienced hypotension and one patient had a vasovagal episode with enprofylline treatment. Both agents acted as bronchodilators with similar efficacy in patients with acute asthma in this study.

Acute Disease↗
PubMed1984

Two patients with abnormalities of regional sympathetic nervous tone.

The traditional biochemical tests of sympathetic nervous system function used in clinical diagnosis (urine and plasma catecholamine measurements) are indices of "overall" sympathetic nervous activity, and incapable of detecting localised changes in sympathetic tone confined to individual organs. Recently developed radiotracer methods, which enable the pattern of sympathetic nervous dysfunction in disease states to be delineated, were used to detect abnormalities in regional sympathetic nervous system activity in two patients presenting problems in management. In one, the abnormality of sympathetic function was iatrogenic, a post-sympathectomy denervation of the lower regions of the body, associated with incapacitating postural hypotension. In the other, unexplained persistent sinus tachycardia proved to be due to an increase in sympathetic nervous tone restricted to the innervation of the heart. Knowledge of the underlying sympathetic nervous pathophysiology in these patients influenced the choice of drugs subsequently used in their treatment.

Dihydroergotamine↗