Allergy to laboratory animals: a retrospective and a prospective study.

Twenty four volunteers who had been allergic to laboratory animals for some years were examined by means of a questionnaire paying particular attention to symptoms associated with rats and by serological and skin tests with extracts of rat urine (retrospective study). Nasal and eye symptoms were reported by 21 and 16 individuals respectively: 13 had asthma. Positive skin tests and high levels of specific IgE antibody to rat urine extract were found in 17 of the more severely affected individuals and this group included 12 of those with asthma. Latent periods of work with animals before symptoms appeared varied from 0.5 to 12 years. Also 148 individuals were studied during their first year of work with animals (prospective study). Symptoms developing during the year were reported by 15%, asthma by 2%. IgE antibody levels to rat urine were raised in 40% of affected and 6% of the unaffected individuals but there was no significant correlation between symptoms and either antibody levels or positive skin tests. Allergic symptoms developing during the first year of postemployment were, on the whole, much milder than those seen in the retrospective study. A tentative conclusion is that most individuals who become allergic to laboratory animals develop the condition in a mild form during their first year of employment but it appears probable that atopic individuals, although having an equal chance of developing allergy as compared with non-atopic individuals, may eventually progress to a more severe form of the disease.     

Detection of the carrier state of X-linked retinoschisis

We determined the extent of suppressive rod-cone interaction in 11 obligate carriers and eight potential carriers of X-linked retinoschisis from eight families. Despite otherwise normal ophthalmoscopic and functional testing, all of the obligate heterozygous carriers demonstrated a complete absence of normal rod-cone interaction. Of the potential heterozygous carriers, three had normal rod-cone interactions, two had no detectable interaction, and two yielded technically unsatisfactory results. This lack of rod-cone interactions allows heterozygous individuals to be identified clinically and has implications concerning the origin of this inherited disorder.     

Benign intracranial hypertension and recombinant growth hormone therapy in Australia and New Zealand

Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml ^-1), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml ^-1) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-² week^-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis.     

Demonstration of human papillomavirus types 6 and 11 in juvenile laryngeal papillomatosis by in-situ DNA hybridization

A study is reported in which an in situ hybridization technique for the demonstration of human papillomavirus (HPV) employing a biotin--streptavidin polyalkaline phosphatase complex has been successfully applied to formalin-fixed paraffin-processed tissue obtained from ten patients with juvenile laryngeal papillomatosis. In all cases, positive results were obtained for either HPV type 6 or 11. Normal vocal cord epithelium was negative.     

Autosomal dominant retinitis pigmentosa mapping to chromosome 7p exhibits variable expression.

The genetic locus causing autosomal dominant retinitis pigmentosa (adRP) has recently been mapped in a large English family to chromosome 7p. Eight affected members of this family were studied electrophysiologically and psychophysically with dark adapted static threshold perimetry and dark adaptometry. The phenotypes observed fell into three categories: minimally affected with no symptoms, and normal (or near normal) electrophysiology and psychophysics; moderately affected with mild symptoms, abnormal electroretinograms, and equal loss of rod and cone function in affected areas of the retina; and severely affected with extinguished electroretinograms and barely detectable dark adapted static threshold sensitivities. The mutation in the gene on 7p causing adRP in this family causes regional retinal dysfunction with greatly variable expressivity ranging from normal to profoundly abnormal in a manner not explained by age.