Osteopetrosis: MR characteristics at 1.5 T

Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements.     

Antibodies against the beta subunit of voltage-dependent calcium channels in Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome is an autoimmune disease that impairs neuromuscular transmission. Several studies suggest that neurotransmitter release is reduced by an immune response directed against the calcium channel complex of nerve terminals. The immunoglobulin G fractions from Lambert-Eaton myasthenic syndrome patients immunoprecipitate solubilized neuronal N- and P/Q-type channels and in certain cases brain, skeletal and cardiac muscle L-type channels [El Far O. et al. (1995) J. Neurochem. 64, 1696-1702; Lennon V. A. and Lambert E. H. (1989) Mayo Clin. Proc. 64, 1498-1504; Sher E. et al. (1989) Lancet ii, 640-643; Suenaga A. et al. (1996) Muscle Nerve 19, 1166-1168]. These channel immunoprecipitation assays are considered as useful for the diagnosis of this syndrome. In this study, we demonstrate that two predominant neuronal voltage-dependent calcium channel beta subunits (beta3 and beta4, of mol. wt 58,000) are general targets of Lambert-Eaton myasthenic syndrome autoantibodies. Of 20 disease sera tested, 55% were able to immunoprecipitate 35S-labeled beta subunits. All five patients affected with small-cell lung carcinoma were positive for the beta-subunit immunoprecipitation assay. Interestingly, only a fraction of the beta-subunit-positive sera was also able to immunoprecipitate N- and P/Q-type channels, suggesting that several of the beta-subunit epitopes are masked in native channels. In accordance with this observation, we found that several beta-positive sera were able to prevent the interaction between calcium channel alpha1 and beta subunits in vitro. In cases where sera were able to immunoprecipitate beta subunits, N- and P/Q-type channels, the immunoprecipitation of both channel types was either partially or entirely mediated by beta-subunit antibodies. Our results suggest that assays based on the immunoprecipitation of beta subunits can be used as an additional test to assist in the diagnosis of Lambert-Eaton myasthenic syndrome.     

Age and sex differences in the management of ischaemic heart disease

Objective

To investigate age and sex differences in the utilisation of hospital services for ischaemic heart disease.

Design

Analysis of routine mortality data and hospital activity data.

Setting

South West Thames Regional Health Authority.

Subjects

Residents of the South West Thames Regional Health Authority who in 1991 either died from ischaemic heart disease or were admitted to an NHS hospital in England and Wales with a main diagnosis of ischaemic heart disease.

Main outcome measures

Ratio of consultant episodes to deaths from ischaemic heart disease (as a proxymeasure of the utilisation of hospital care), and the percentages of consultant episodes in which further investigation (angiography or catheterisation) or revascularisation treatment (coronary artery bypass grafting or angioplasty) were carried out.

Results

The ratio of episodes to deaths was similar in men and women (odds ratio for men vs. women 0.96, 95% confidence intervals 0.90 to 1.03). The percentage of episodes in which further investigation was carried out was higher in men than women (odds ratio for men vs. women 1.46, 95% confidence intervals 1.25 to 1.70) as was the percentage of episodes in which revascularisation treatment was carried out (odds ratio for men vs. women 1.46, 95% confidence intervals 1.20 to 1.77). The ratio of episodes to deaths, the percentage of episodes in which further investigation was carried out, and the percentage of episodes in which revascularisation treatment was carried out all declined with age (all p values <0.001).

Conclusions

Women with ischaemic heart disease are as likely as men to be admitted to hospital, but afteradmission are less likely to undergo further investigation and revascularisation treatment. Elderly patients with ischaemic heart disease are less likely than younger patients to be admitted to hospital; after admission, they are also less likely to undergo further investigation and revascularisation treatment. Further research is needed to determine whether these age and sex differences in the use of hospital services are clinically justified.