Magnesium status and digoxin toxicity.

1. Eighty-one hospital patients receiving digoxin were separated into groups with and without digoxin toxicity using clinical criteria. Serum digoxin, sodium, potassium, calcium, creatinine, magnesium and monocyte magnesium concentrations were compared. 2. Subjects with digoxin toxicity had impaired colour vision (P less than 0.0001, Farnsworth-Munsell 100 hue test) and increased digoxin levels (1.89 (1.56-2.21) vs 1.34 (1.20-1.47) nmol l-1, P less than 0.01) (mean (95% confidence limits], though there was considerable overlap between two groups. 3. Subjects with digoxin toxicity had lower levels of serum magnesium (0.80 (0.76-0.84) vs 0.88 (0.85-0.91) mmol l-1, P less than 0.01) and monocyte magnesium (6.40 (5.65-7.16) vs 8.76 (7.81-9.71) mg g-1 DNA, P less than 0.01), but there were no significant differences in other biochemical parameters. A greater proportion of toxic subjects were receiving concomitant diuretic therapy (20/21 vs 37/60, P less than 0.05). 4. Magnesium deficiency was the most frequently identified significant electrolyte disturbance in relation to digoxin toxicity. In the presence of magnesium deficiency digoxin toxicity developed at relatively low serum digoxin concentrations.     

Failure of gallium-67 citrate imaging to diagnose post-myocardial infarction (Dressler's) syndrome

Gallium-67 scanning has been suggested as a means of diagnosing post-pericardiotomy syndrome. We have assessed the value of thoracic gallium scanning in patients with the post-myocardial infarction (Dressler's) syndrome, which is thought to have a similar pathogenesis. In five patients in whom the diagnosis was established by currently available means, ⁶⁷Ga scans performed during active pericarditis showed no significant uptake in any case. No subject was receiving steroids but all were taking nonsteroid anti-inflammatory drugs at the time of scanning. It is not clear why there should be differences in gallium uptake between the two conditions, but we conclude that ⁶⁷Ga thoracic scanning is of no value in the management of patients with Dressler's syndrome.     

In vivo and in vitro studies into the immunological changes following iodine 131 therapy for Graves' disease

Radio-iodine therapy for Graves' disease is followed by immunological changes in addition to effects on thyroid hormone production. The present study examined these changes and the mechanisms responsible for them. Of the 15 patients enrolled in the study, 10 became hypothyroid in the first year after iodine 131 therapy. Patients who became hypothyroid had a tendency to show a rise in serum thyrotropin receptor antibody levels (30 ± 14 to 40 ± 9 units; NS) and a significant rise in immunoglobulin production (324 ± 153 to 740 ±200 ng/ml; P < 0.0005) from mitogen-stimulated peripheral blood lymphocytes (a measure of B-cell activity) 2 months after iodine 131 therapy. The increases were not seen in the patients who remained euthyroid at 1 year. In vitro studies suggested that the rise in B-cell activity is due to a fall in suppressor T cell numbers, a change shown to occur following iodine 131 therapy in previous studies. Our results indicate that immunological changes do arise after iodine 131 therapy for Graves' disease but appear to be confined to patients who subsequently became hypothyroid. It is not possible from this study to determine whether the immunological changes appear as a consequence of thyroidal destruction leading to hypothyroidism or whether they contribute directly to it. Offprint requests to: R. Wilson     

Mediastinal imaging in lung cancer

Sixty-six patients with lung cancer underwent mediastinal staging with gallium scanning, CT scanning and mediastinal exploration at mediastinoscopy and/or thoracotomy. Histological findings at time of mediastinal exploration were correlated with the results of the non-invasive staging scans. Gallium scanning had an accuracy of 78.8 per cent and CT scanning had an accuracy of 77.3 per cent. There was no evidence of increased test accuracy by performing both scans in the same individual. Either scanning technique may be utilised as a simple non-invasive mediastinal staging procedure, and where negative it is appropriate to proceed directly to thoracotomy.     

Clinical analysis in intact erythrocytes using 1H spin echo NMR.

A new method of clinical analysis based on 1H spin echo NMR spectroscopy is presented. It is capable of providing information on six metabolites within viable erythrocytes, directly and without any preparative procedures prior to analysis except for cell separation and washing. Erythrocytes from patients with rheumatoid arthritis and Graves' disease are compared with cells obtained from healthy volunteers. The NMR detectable species in the cytosol of the cells are glutathione, ergothioneine, choline, creatine, glycine, lactate and to a lesser extent alanine and valine. Significant differences are observed between the ergothioneine pools in the rheumatoid group (P less than 0.01) compared to the control group. The glutathione: di-glutathione ratio can be assessed from the ratio, g2 to g4, taken from different signals in the glutathione molecule. The total concentration of glutathione present is easily assessed qualitatively but is more difficult to quantitate.     

Septic arthritis of the manubriosternal joint

Pyarthrosis of the manubriosternal joint is exceedingly rare. Its rarity defies an early diagnosis, and other causes of chest pain would normally be ruled out first. We describe a patient with a short history of chest pain, pyrexia, and raised inflammatory markers. A destroyed manubriosternal joint with a large abscess was found during surgical exploration. This case illustrates an unusually rapid development of septic arthritis involving a fibrocartilaginous joint in an otherwise healthy young man. Nine other cases have been described in the literature and are reviewed. Early diagnosis followed by adequate surgical drainage and antibiotic therapy led to a good outcome.     

Myxoma virus M130R is a novel virulence factor required for lethal myxomatosis in rabbits

Myxoma virus (MV) is a highly lethal, rabbit-specific poxvirus that induces a disease called myxomatosis in European rabbits. In an effort to understand the function of predicted immunomodulatory genes we have deleted various viral genes from MV and tested the ability of these knockout viruses to induce lethal myxomatosis. MV encodes a unique 15 kD cytoplasmic protein (M130R) that is expressed late (12 h post infection) during infection. M130R is a non-essential gene for MV replication in rabbit, monkey or human cell lines. Construction of a targeted gene knockout virus (vMyx130KO) and infection of susceptible rabbits demonstrate that the M130R knockout virus is attenuated and that loss of M130R expression allows the rabbit host immune system to effectively respond to and control the lethal effects of MV. M130R expression is a bona fide poxviral virulence factor necessary for full and lethal development of myxomatosis.     

Validation of Resource Utilization Groups version III for Home Care (RUG-III/HC): evidence from a Canadian home care jurisdiction

BACKGROUND: The case-mix system Resource Utilization Groups version III for Home Care (RUG-III/HC) was derived using a modest data sample from Michigan, but to date no comprehensive large scale validation has been done. OBJECTIVES: This work examines the performance of the RUG-III/HC classification using a large sample from Ontario, Canada. METHODS: Cost episodes over a 13-week period were aggregated from individual level client billing records and matched to assessment information collected using the Resident Assessment Instrument for Home Care, from which classification rules for RUG-III/HC are drawn. The dependent variable, service cost, was constructed using formal services plus informal care valued at approximately one-half that of a replacement worker. RESULTS: An analytic dataset of 29,921 episodes showed a skewed distribution with over 56% of cases falling into the lowest hierarchical level, reduced physical functions. Case-mix index values for formal and informal cost showed very close similarities to those found in the Michigan derivation. Explained variance for a function of combined formal and informal cost was 37.3% (20.5% for formal cost alone), with personal support services as well as informal care showing the strongest fit to the RUG-III/HC classification. CONCLUSIONS: RUG-III/HC validates well compared with the Michigan derivation work. Potential enhancements to the present classification should consider the large numbers of undifferentiated cases in the reduced physical function group, and the low explained variance for professional disciplines.