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Biomedical subjects

R D Aldridge

Publications and source records attributed to R D Aldridge.

At least 37 records · Page 2Linked to original sources
PubMed1993

Linear lichen planus and lichen striatus--opposite ends of a spectrum.

The linear pattern of lichen planus (LP) is extremely rare. In six publications 1256 patients with LP have been reviewed and only three cases of linear LP (LLP) are reported. The differential diagnosis of LLP includes a number of linear dermatoses in particular lichen striatus (LS) and the extent of overlap between these syndromes remains contentious.

Adult↗
PubMed1991

Cowpox/catpox infection.

A 19-year-old veterinary nurse developed a cowpox/catpox virus (CPV) infection of her right third finger following a scratch from a tom cat suffering from pneumonia. The clinical course and investigation of the infection are described and the differential diagnosis discussed.

Adult↗
PubMed1991

Lymphocyte transformation and thiuram sensitization.

The use of a lymphocyte transformation test (LTT) to confirm allergic contact dermatitis from thiurams has been investigated. The responses of peripheral blood mononuclear cells (PBMC) from thiuram-sensitive and non-sensitive individuals following culture with dimethylcarbamoyl-protein (human serum albumin; HSA) and dimethylthiocarbamoyl-HSA conjugates has been compared. Only PBMC from those patients who were patch-test-positive with thiuram-mix and sensitized to tetramethylthiuram monosulphide (TMTM) or TMTM and tetramethylthiuram disulphide (TMTD) exhibited significant proliferative responses to these conjugates. Thiuram-patch-test-negative patients and control donors with no history of allergic contact dermatitis failed to mount a significant response to any concentration of either conjugate. Two of the thiuram-sensitive patients were also nickel-patch-test-positive, and PBMC isolated from these donors, but not from nickel-patch-test-negative patients, proved positive in a nickel LTT. The data reveal that relevant hapten-protein conjugates are capable of provoking specific human lymphocyte proliferative responses in vitro, and that, using this technique, the LTT can, in principle, be used for the investigation and/or diagnosis of skin sensitization to lipophilic contact allergens.

Cell Division↗
PubMed1989

Polyamine sensitization in offshore workers handling drilling muds.

Oil-based mud, a complex mixture containing amines in emulsifiers, is used in offshore drilling operations. It is a skin irritant that occasionally gives rise to allergic contact sensitivity. In patch testing patients with allergy to drilling mud, we have identified polyamine (diethylenetriamine and triethylenetetramine) sensitivity in 5 patients. All 5 patients were also allergic to emulsifiers. These emulsifiers are cross-linked fatty acid amido-amines, in which unreacted amine groups are thought to cross-sensitize with these constituent polyamines. Cross-reactivity between ethylenediamine, diethylenetetramine and triethylenetetramine was found in 9 subjects.

Adult↗
PubMed1986

Progressive multifocal leukoencephalopathy complicating systemic lupus erythematosus.

Two patients with systemic lupus erythematosus who developed progressive multifocal leukoencephalopathy (PML) are described. Although the time of PML onset could not be determined with certainty, it probably developed after steroid-induced immunosuppression. However, high-dose corticosteroids appeared to produce transient amelioration in the neurologic disorder. We suggest that PML is an important addition to the list of conditions to be considered in the differential diagnosis when a patient with systemic lupus erythematosus develops neurologic abnormalities.

Adult↗
PubMed1986

Inhibition of drug-induced eosinophilia by cyclosporin A.

Administration of cyclophosphamide to Sprague-Dawley rats 2 days before immunization with ovalbumin in complete Freund's adjuvant resulted in a striking blood, bone marrow, and tissue eosinophilia. The number of circulating eosinophils reached a maximum (50-fold increase above normal) 2 weeks after immunization, and eosinophils were also prominent in bone marrow, lymph nodes (paracortical areas), spleen (white and red pulp), and liver. The eosinophilia could be inhibited by daily oral administration of cyclosporin A (CsA), although its effect was dependent both on the duration of treatment and on the dosage of CsA. A similar, inhibitory action of CsA was demonstrated with respect to methotrexate-induced eosinophilia. This experimental model may prove useful in the study of factors regulating eosinophil production and in examining the prospective value of CsA in the treatment of conditions where eosinophils play a central role.

Animals↗
PubMed1986

Paradoxical augmentation of tuberculin-like hypersensitivity, but not Jones-Mote or contact hypersensitivity, in cyclosporin A treated guinea pigs.

Administration of cyclosporin A (CsA; 25 mg/kg) orally to guinea pigs from the time of immunization with ovalbumin (OVA) in complete Freund's adjuvant, followed by drug withdrawal 4 days later, resulted in marked potentiation of classical, tuberculin-like delayed-hypersensitivity skin responses to OVA. However, no such augmentation of delayed-type hypersensitivity (DTH) to purified protein derivative (PPD) was demonstrated. The enhancing effect of CsA was also dependent on the dose of OVA used for both immunization and skin testing and on the interval between drug withdrawal and the elicitation of DTH. A single intraperitoneal injection of CsA (200 mg/kg) given 2 days before immunization also had an augmentary effect on 14-day responses to OVA. Similar treatment protocols, however, did not enhance Jones-Mote (cutaneous basophil) hypersensitivity to OVA or contact sensitivity reactions to dinitrofluorobenzene. Longer courses of CsA (25 mg/kg per os) between sensitization and skin testing severely depressed all three categories of type IV hypersensitivity reactions. Our observations may have important cautionary implications for the prospective management of immunologically mediated diseases of intermittent activity, including certain autoimmune disorders, where short courses of CsA might be contemplated.

Animals↗
PubMed1986

Factors influencing the enhancement of delayed-type hypersensitivity to ovalbumin by cyclosporin A in the guinea pig: possible role of suppressor cells.

Enhancement of delayed-type hypersensitivity (DTH) reactions to ovalbumin (OVA) was demonstrated in guinea pigs given a single, high dose of cyclosporin A (CsA) intraperitoneally, 2 days before immunization. Courses of oral CsA, commencing at the time of immunization and lasting until day 4 or 13 also resulted in augmented DTH responses at days 14 and 28, respectively. However, the enhancing protocol (CsA; day 0-4) did not significantly affect circulating anti-OVA antibody titres. The capacity to express increased DTH could be adoptively transferred to naive recipients by systemic injection pooled spleen and peritoneal exudate cells. Moreover, the expression of augmented responses was inhibited by transfer of cells from normally immunized donors. Although augmentation of DTH was accompanied by increased lymphocyte proliferative responses to OVA in vitro, there was no similar effect on T cell responses to polyclonal mitogens. The data support the view that augmentation of DTH by CsA is attributable to suppressor cell dysfunction, but that this is unlikely to be a non-specific suppressor cell impairment.

Animals↗
PubMed1986

Topical cyclosporin A in nickel contact hypersensitivity: results of a preliminary clinical and immunohistochemical investigation.

Four out of eighteen (22%) patients with nickel contact sensitivity showed inhibition of skin patch test responses to the allergen in the presence of topical cyclosporin A (CsA; 5% v/v). No systemic drug absorption or side effects were detected. The clinical response to CsA was accompanied by marked diminution of the T cell infiltrate, although no alteration in the helper/suppressor cell ratio was observed. Expression of the Leu 6 marker on epidermal Langerhans cells and of major histocompatibility complex (MHC) class II antigens (HLA-DR, DQ and DP) on lymphocytes and Langerhans cells was unaffected by topical CsA. The incidence of IL-2 receptor positive lymphocytes in all biopsies was too small to ascertain the influence, if any, of CsA. The prospective use and method of application of CsA in immune contact dermatitis and other immunologically-based skin disorders warrants further evaluation.

Adolescent↗
PubMed1986

Cyclosporine-induced renal structural damage: influence of dosage, strain, age and sex with reference to the rat and guinea pig.

Cyclosporine (CsA)-induced renal structural damage was investigated in rats of different strains, age and sex, and in outbred guinea pigs, given the drug orally for periods of 1 to 7 weeks. In adult male Sprague-Dawley (SD) rats, proximal straight tubular (PST) cell vacuolation and nuclear pyknosis (affecting less than 5% of tubular profiles) can consistently be demonstrated by light microscopy within a few days of commencement of treatment with 25 mg/kg. The extent of damage observed with longer term, continuous drug administration is generally more pronounced, dose-related and subject to "spontaneous" remission. Comparison of SD with DA male rats undergoing similar treatment shows that at 4 weeks, structural damage is less pronounced in the latter strain. In juvenile (LEW X DA)F1 hybrids, male animals exhibit greater susceptibility to CsA-induced nephrotoxicity than do females. This is related to differences in circulating levels of CsA in males and females. However, in adult SD rats both male and female animals show almost the same degree of tubular nephrotoxicity when given the drug at 50 mg/kg. Use of the electron microscope improves detection of early and minimal tubular cell damage: for example, in guinea pigs receiving 75 mg/kg orally for 4 days, ultrastructural changes are evident although the renal tubules are apparently unaffected when examined by light microscopy.

Age Factors↗