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Biomedical subjects

A R Halbert

Publications and source records attributed to A R Halbert.

9 recordsLinked to original sources

Characteristics and outcome of t(8;21)-positive childhood acute myeloid leukemia: a single institution's experience.

To elucidate the clinical and biological features of childhood acute myeloid leukemia (AML) with the t(8;21), we reviewed the records of patients with AML treated at St Jude Children's Research Hospital over a 17-year period (1980 to 1996). Of 298 patients with AML, 40 (13%) had blast cells that contained the t(8;21). This translocation was associated with a high frequency of French-American-British M2 morphology (82%) and the presence of granulocytic sarcoma (23%). Molecular analysis detected the AML1-ETO fusion transcript in all 25 cases with the t(8;21) tested, but failed to identify additional cases with AML1-ETO among the 127 cases with other cytogenetic findings. Compared to patients with other genetic abnormalities, those with the t(8;21) were less likely to have internal tandem duplications of the FLT3 gene (none of 10 vs 16 of 68). The 6-year overall survival estimate was 55% +/- 9% and the event-free survival estimate, 33% +/- 7%. Of the clinical and biological features examined, only gender was prognostically significant: the 6-year overall survival estimate for males was 68% +/- 10%, compared to 33% +/- 11 for female patients (P = 0.03). Treatment outcome was not influenced by the chemotherapy regimen used or by the use of autologous hematopoietic stem cell transplantation. These results suggest that t(8;21)-positive AML represents a heterogeneous disease with variable outcome. The reported favorable outcome for t(8;21)-positive AML in other studies may be due to the use of high-dose cytarabine.

Acute Disease↗

Cytogenetic analysis of a scapular chondromyxoid fibroma.

Chondromyxoid fibroma (CMF) is a rare cartilaginous tumor of bone. It typically presents in the lower extremities of young males. Cytogenetic analysis of two chondromyxoid fibromas has been previously reported. We studied a scapular CMF from an 11-year-old female by cytogenetic and molecular cytogenetic methods and found an unbalanced reciprocal translocation between the short arm of chromosome 3 and the long arm of chromosome 6. In this translocation, several bands from chromosome 3 (3p12, 3p13, 3p14, 3p21) are lost and several bands on chromosome 6 (6q21, 6q22, 6q23) appear rearranged. Two known cartilage-related genes are located in the regions affected by this unbalanced rearrangement: the type X collagen gene (COL10A1) located at 6q21-q22 and the parathyroid hormone/parathyroid hormone-related peptide receptor gene (PTH/PTHrP) located at 3p21.1-p22. These genes function to control growth and maturation of endochondral bone, the site of origin of cartilaginous tumors.

Bone Neoplasms↗

Juvenile dermatomyositis.

Juvenile dermatomyositis (JDMS) is a chronic inflammatory condition characterized by muscle weakness and a distinctive rash caused by underlying vasculopathy. Long-term complications include subcutaneous and muscular calcification, contractures and in some cases the gradual development of a second connective tissue disease. Early aggressive treatment with systemic immunosuppressants and other agents such as intravenous immunoglobulin (IVIG) reduces mortality and morbidity.

Calcinosis↗

Atopic dermatitis: is it an allergic disease?

For many years controversy has surrounded the relation between allergy and atopic dermatitis. We critically review the evidence for the contribution of allergy, or IgE-mediated hypersensitivity reactions, to the pathogenesis of this disease. We conclude that, at present, there is scant evidence that allergy is central to the development of atopic dermatitis, although it may be an aggravating factor in a few patients. Hence there is little rationale for the routine use of allergy testing or dietary and environmental manipulation in the management of this disease.

Allergens↗

Discoid lupus erythematosus.

Discoid lupus erythematosus is a manifestation of chronic cutaneous lupus erythematosus with a small risk of systemic involvement. In this review article, the role of predisposing factors such as haplotype, hormones, antibodies and sunlight are discussed. The clinical features, including variants and associations, and management options are presented.

Fluorescent Antibody Technique↗

The effect of bacterial colonization on venous ulcer healing.

To determine the effect of bacterial colonization on venous ulcer healing, 82 patients with 100 venous ulcerated limbs were each studied prospectively for six months. Despite bacteriological swab results, topical or systemic antibiotics were not administered unless cellulitis supervened. Initial ulcer size, length of ulcer history and time to complete healing of colonized and uncolonized ulcers were determined and compared. Organisms were cultured from 83 limbs prior to commencement of treatment, the commonest isolates being Staphylococcus aureaus (48%), mixed coliforms (28%), Pseudomonas aeruginosa (21%) and anaerobes (17%). When compared with ulcers with no bacterial growth, colonized ulcers were of longer duration (p [symbol: see text] 0.01), had a larger initial size (p [symbol: see text] 0.001) and had significantly longer healing time (p [symbol: see text] 0.001). When analysed individually beta-haemolytic streptococci, anaerobes, Staphylococcus aureus and coliforms were associated with delayed healing. Delayed healing was not found with Pseudomonas aeruginosa, although pseudomonas-colonized ulcers were significantly larger and of longer duration than uncolonized ulcers. Bacterial colonization is associated with delayed venous ulcer healing. To further clarify the pathogenicity of colonizing bacteria, however, the effect of their eradiction on healing of venous ulcers needs to be established.

Adult↗

Prognosis of occupational chromate dermatitis.

To elucidate further the natural history and prognosis of occupational chromate dermatitis, 120 affected patients, diagnosed between 1980 and 1989, were reviewed. The incidence of chromate dermatitis in Western Australia appeared to remain unchanged over the decade. 65% of patients were construction workers with cement-induced chromate dermatitis. Workers at greatest risk of sensitization were those mixing bagged cement at the work site. The median age at onset of symptoms was 34 years, with 48% having been exposed to chromate for 5 years or less. Only 37% presented to the dermatologist within 12 months of developing symptoms. 76% of patients had ongoing dermatitis at the time of review. Although 48% of the study population had completely changed their occupation to avoid chromate exposure, symptoms persisted in 69%. A delayed diagnosis of chromate sensitivity was noted to be a predictor of chronicity. In view of the potential chronicity of chromate dermatitis and its associated social and occupational impairment, we recommend the addition of ferrous sulphate while mixing bagged cement at the work site. This simple technique targets the workers at greatest risk of becoming sensitized.

Adolescent↗