'Epinephrine-resistant' angioedema.

A man in his 60s was brought to the emergency department, with airway compromise and dysarthria due to a grossly enlarged tongue. As he was on a current course of antibiotics, he was treated for a likely antibiotic-associated allergic reaction. However, as he failed to improve with intramuscular and nebulised epinephrine, another cause of his symptoms was sought. Further discussion revealed a history of chronic lymphocytic leukaemia (CLL), which had recently relapsed. Investigations were ordered to confirm that the symptoms were due to acquired angioedema, and the patient was managed for this diagnosis based on the presence of an undetectable C4 level. This diagnosis was later confirmed when the results of specialist tests became available. The patient was treated for his relapsed CLL with good effect, and has had no further episodes of angioedema and an improvement in the level of his C1 esterase protein level and function.

Occult bone marrow involvement in patients with diffuse large B-cell lymphoma: results of a pilot study.

AIMS: It is known that advanced stage disease in diffuse large B-cell lymphoma (DLBCL) confers a poor prognosis, and staging investigations are routinely performed at diagnosis, including a bone marrow (BM) biopsy. However, examination of the BM is usually limited to routine light microscopy, with the role of ancillary investigations remaining unestablished. The aim of this pilot study was to estimate the incidence of occult marrow involvement using flow cytometry, immunohistochemistry and immunoglobulin heavy chain (IgH) gene rearrangements, and to determine the impact on survival. METHODS: Clinical and pathological data were obtained on 36 patients diagnosed with DLBCL. Immunohistochemistry using CD3, CD45RO, CD20 and CD79a, and polymerase chain reaction (PCR) to look for IgH gene rearrangements were performed on formalin fixed BM trephines. RESULTS: Nine patients had morphologically apparent BM involvement. Occult marrow involvement was found in seven of 36 (19.4%) patients using the additional diagnostic modalities. When these cases were included with morphologically apparent cases in a proposed new definition of marrow involvement, the median survival of patients with BM involvement was statistically worse (p=0.02) than those without involvement. CONCLUSIONS: The results indicate that use of additional tests on BM at diagnosis can upstage disease for a proportion of patients, which appears to correlate adversely with survival.

Modular decomposition of metabolic systems via null-space analysis.

We describe a method by which the reactions in a metabolic system may be grouped hierarchically into sets of modules to form a metabolic reaction tree. In contrast to previous approaches, the method described here takes into account the fact that, in a viable network, reactions must be capable of sustaining a steady-state flux. In order to achieve this decomposition we introduce a new concept--the reaction correlation coefficient, phi, and show that this is a logical extension of the concept of enzyme (or reaction) subsets. In addition to their application to modular decomposition, reaction correlation coefficients have a number of other interesting properties, including a convenient means for identifying disconnected subnetworks in a system and potential applications to metabolic engineering. The method computes reaction correlation coefficients from an orthonormal basis of the null-space of the stoichiometry matrix. We show that reaction correlation coefficients are uniquely defined, even though the basis of the null-space is not. Once a complete set of reaction correlation coefficients is calculated, a metabolic reaction tree can be determined through the application of standard programming techniques. Computation of the reaction correlation coefficients, and the subsequent construction of the metabolic reaction tree is readily achievable for genome-scale models using a commodity desk-top PC.

Immune thrombocytopenia after renal transplantation for IgA nephropathy.

Immune thrombocytopenic purpura associated with renal disease is usually therapy-related, occurring after administration of intravenous immunoglobulin therapy or anti-D. Secondary cases occurring after renal transplantation are extremely rare. We present the second reported case of immune thrombocytopenic purpura occurring after renal transplantation for IgA nephropathy. Primary IgA nephropathy is the most common form of primary glomerulonephritis and although the pathogenesis of the disease remains incompletely understood, recent evidence suggests that the basic abnormality lies within the IgA immune system rather than in the kidney. We postulate a novel mechanism for thrombocytopenia occurring in such cases.

A probe for organ impedance measurement.

In this paper, we describe the theory and practical implementation of an electrical impedance probe for making in vivo measurements of the electrical admittance of living tissue. The probe uses concentric annular electrodes and is shown to sample a more localized, yet greater, volume of tissue than the standard four-electrode probe. We have developed a mathematical model for the conduction of current between the probe electrodes assuming that we are investigating a uniform, isotropic, semi-infinite region and taking into account the contact impedance between the electrodes and the organ. The electric fields produced by the probe have been calculated by solving a weakly singular Fredholm integral equation of the second kind. The size and position of the probe electrodes have been optimized to maximize both the accuracy in the admittance measurement and insensitivity to contact impedance. A probe and driving hardware have been constructed and experimental results are provided showing the accuracy of admittance measurements at 50 and 640 KHz.