Recovery from desensitization of IgE-dependent responses in human lung mast cells.

BACKGROUND: Clinical desensitization and oral food immunotherapy are therapeutic interventions that allow individuals who react adversely to an allergen (drug or food) to be made tolerant to the allergen. However, tolerance is brief, and allergen hypersensitivity can recur within days following allergen withdrawal. OBJECTIVE: We hypothesize that the reason these treatments are temporary reflects rapid recovery of mast cells from a desensitized state. We sought to test this. METHODS: Desensitization of IgE-mediated histamine release from human lung mast cells was explored by methods that partially replicate the pattern of treatment during clinical desensitization. Specific and non-specific desensitization and changes in surface IgE were examined following desensitization. Recovery from desensitization was also studied. RESULTS: Desensitization of mast cell responses was readily induced with concentrations of antigen or anti-IgE that were suboptimal for secretion. There was little or no non-specific desensitization when lung mast cells were exposed to antigens. There was no loss of cell surface IgE following desensitization. Removing the desensitizing stimulus from the media following desensitization allowed the cells to recover with half-point of recovery of ~1.5 days and complete recovery after 5 days. Both the functional response and histamine content recovered within this time frame. The recovery appeared possible because both antigens and anti-IgE dissociated rapidly from cells after washing to remove excess stimulus. CONCLUSIONS AND CLINICAL RELEVANCE: Human lung mast cells readily recover from a desensitized state following removal of desensitizing antigen. This finding provides a potential explanation for the ephemeral nature of clinical desensitization.

Heterogeneity in the responses of human lung mast cells to stem cell factor.

BACKGROUND: Stem cell factor (SCF) is a growth factor that is involved in mast cell differentiation and proliferation. SCF primes human lung mast cells for enhanced responses to IgE-directed activation but is not generally recognized as a direct activator. SCF mediates its effects through c-kit. OBJECTIVE: The aim of this study was to reappraise the effects of SCF on human lung mast cells. METHODS: Mast cells were isolated from human lung. Mast cells were challenged with anti-IgE or SCF and the generation of histamine, cysteinyl-leukotrienes (cys-LTs) and prostaglandin D(2) (PGD(2) ) was assessed as was expression of the activation marker, CD63. The effects of c-kit inhibitors on mediator release were evaluated. RESULTS: Stem cell factor (10 ng/mL) alone was unable to induce mediator release but primed mast cells for enhanced IgE-dependent secretion. At higher concentrations (≥ 30 ng/mL), SCF had more varied effects and even when used alone was able to drive substantial levels of histamine release in about a third of all preparations studied. Similarly, SCF (100 ng/mL) alone was effective in stimulating the generation of cys-LTs in half of the preparations studied. SCF (100 ng/mL) was even more effective at stimulating PGD(2) generation as almost all preparations generated substantial quantities of the prostanoid. Mediator release induced by SCF was accompanied by the up-regulation of the activation marker, CD63. There was a positive correlation between the extent of mediator release induced by SCF and c-kit receptor expression. The effects of SCF on mediator release from mast cells were reversed by the c-kit inhibitor imatinib. CONCLUSIONS AND CLINICAL RELEVANCE: These data demonstrate that the responses of mast cells to SCF are heterogeneous. SCF can drive much greater levels of mediator release from mast cells, especially of PGD(2), than hitherto appreciated and this could be important in the context of respiratory diseases.

Sudden cardiac deaths in young British Army personnel.

Much attention has been paid to sudden cardiac death in young athletes which has led to the implementation of tighter screening controls in many sports at various levels. Less attention has been paid to this subject in young army recruits. We describe three cases of sudden cardiac death in young UK soldiers. The scale of the problem in the UK is unknown. We highlight issues regarding diagnostic testing to identify risk factors for sudden cardiac death and suggest potential additions to the current screening programme for new recruits to help increase the sensitivity of detecting cardiac pathology and reducing the rates of sudden cardiac death in this group.

National guidelines for adult autopsy cardiac dissection and diagnosis--are they achievable? A personal view.

Adult autopsy cardiac pathology has been previously a quiet backwater of ischaemic heart disease and the occasional cardiomyopathy. This has changed to an increasingly tense area, following recent genetic discoveries and some medicolegal cases. All autopsy pathologists should consider their dissection protocols and check that they are able to deliver the increasingly detailed information that clinicians, geneticists and families require. This text has suggestions about the practical realities of cardiac dissection, cardiac histology and the need for other tests alongside illustrations aimed to assist case consideration.

Interobserver variation in the classification of thymic tumours--a multicentre study using the WHO classification system.

AIMS: To test the reproducibility of the current World Health Organization (WHO) classification of thymic epithelial tumours and to determine the level of interobserver variation within a group of pathologists, all with experience and expertise in thoracic pathology. METHODS AND RESULTS: Ninety-five thymic tumours were circulated to a group of 17 pathologists in the UK and The Netherlands over a 1-year period. Participants were asked to classify them according to WHO criteria. The diagnoses were subjected to statistical analysis and kappa values calculated. The overall level of agreement was moderate (kappa 0.45). When the categories were reduced in number by creating two groups, (A + AB + B1 + B2 and B3 + C), the level of agreement increased to 0.62. An alternative grouping (A + AB + B1 and B2 + B3 + C) increased it slightly further. The best agreement was in tumour types A and AB. Difficulties arose in distinguishing B1 tumours from B2 tumours and B2 tumours from B3 tumours. CONCLUSIONS: Although the WHO system describes a number of well-defined tumour types with clear diagnostic criteria, the overall level of agreement was moderate and improved if some groups were amalgamated.

Influence of beta2-adrenoceptor gene polymorphisms on beta2-adrenoceptor-mediated responses in human lung mast cells.

BACKGROUND AND PURPOSE: Previous studies have shown that beta(2)-adrenoceptor-mediated responses in human lung mast cells are highly variable. The aims of the present study were to establish whether polymorphisms of the beta (2)-adrenoceptor gene (ADRB2) influence this variability in (a) beta(2)-adrenoceptor-mediated inhibition and (b) desensitization of beta(2)-adrenoceptor-mediated responses in human lung mast cells. EXPERIMENTAL APPROACH: Mast cells were isolated from human lung tissue. The inhibitory effects of the beta-adrenoceptor agonist, isoprenaline (10(-10)-10(-5) M), on IgE-mediated histamine release from mast cells were determined (n=92). Moreover, the inhibitory effects of isoprenaline were evaluated following a desensitizing treatment involving long-term (24 h) incubation of mast cells with isoprenaline (10(-6) M) (n=65). A potential influence of polymorphisms on these functional responses was determined by genotyping 11 positions, in the promoter and coding regions, of ADRB2 previously reported as polymorphic. KEY RESULTS: There was no influence of any of the polymorphic positions of ADRB2 on the potency of isoprenaline to inhibit histamine release from mast cells with the exception of position 491C>T (Thr164Ile). There was no influence of any of the polymorphic positions of ADRB2 on the extent of desensitization of the isoprenaline-mediated response following a desensitizing treatment except for position 46G>A (Gly16Arg). Analyses at the haplotype level indicated that there was no influence of haplotype on beta (2)-adrenoceptor-mediated responses in mast cells. CONCLUSIONS AND IMPLICATIONS: These data indicate that certain polymorphisms in ADRB2 influence beta(2)-adrenoceptor-mediated responses in human lung mast cells.

Total hip replacement in a patient with systemic mastocytosis: a case report.

Systemic mastocytosis is a rare condition that often involves the bone marrow. We report the case of a patient with systemic mastocytosis who underwent total hip replacement. Technical difficulties encountered during the procedure included a narrow medullary canal and abnormally hard bone, later confirmed by laboratory measurements. Follow-up at five years showed a good clinical and radiological outcome.

KU activity: a method for calculating histopathologists' workloads.

An attempt to model activity of individual histopathologists or departments is illustrated, in which specimen numbers and types are weighted to produce an overall Kim unit (KU) activity. By cross referencing this numerical score against individual pathologists and clinicians, it is not only possible to interrogate departmental activity retrospectively, but also to predict and cost the impact of any change in service. The advantages over Welcans and Korner Units are illustrated.

Cytodiagnosis and the necropsy.

AIMS: To assess the efficacy of cytodiagnosis in necropsy practice. METHODS: Fifty three focal lesions from 46 necropsies were assessed by direct smears taken from the lesions. The smears were air-dried and stained by a modified Giemsa technique, with two cases having supplementary histochemistry. All of the slides were assessed independently before review of the necropsy histology. RESULTS: Of the 35 malignant neoplasms, 34 were correctly identified as malignant and 14 of these were characterised precisely. Three of the four benign neoplasms were recognised as neoplastic. One was characterised precisely. Three of the four infected cases revealed the relevant microorganisms. Seven of the other 10 focal non-neoplastic lesions were correctly diagnosed as non-neoplastic. Only two cases proved unsatisfactory for cytodiagnosis. CONCLUSIONS: Direct smear cytodiagnosis is quick, cheap and technically simple. Tissue autolysis may account for some difficulty in assessing particular tissues, but this should diminish with experience. Necropsy cytodiagnosis is applicable to all necropsies in all centres.

Necropsy diagnosis of myocarditis: a retrospective study using CD45RO immunohistochemistry.

AIM: To use CD45RO immunohistochemistry to investigate the numbers of T lymphocytes found in sections of myocardium from a routine necropsy series, and to determine the incidence of myocarditis in this series. METHODS: Myocardial sections from 163 routine hospital necropsies were stained with CD45RO and the numbers of positive lymphocytes/mm2 were counted. The results were correlated with the H/E opinion and the clinical context of the necropsy. RESULTS: Most (143) cases showed low numbers (0-3) of CD45RO positive lymphocytes/mm2. Fifteen cases showed 7-13 positive lymphocytes/mm2, comprising a wide variety of clinical conditions, generally with no specific cardiac pathology. Five cases showed 14 or more positive lymphocytes/mm2, comprising one case of active myocarditis, three cases of cardiac transplant rejection, and one post-transplant lymphoproliferative disorder, all conditions in which large numbers of lymphocytes would be expected. CONCLUSIONS: The incidence of myocarditis in our series was 0.6%. In most cases the normal myocardium has a low T lymphocyte count (0-3/mm2). In some cases immunohistochemistry shows more positive cells than would have been expected on light microscopy. Immunohistochemistry is a useful and reliable means of confirming a diagnosis of myocarditis. The results support the conclusion of the 1997 ISFC task force that 14 or more lymphocytes or macrophages/mm2 of myocardium in the appropriate clinical context is a reliable threshold for the diagnosis of chronic myocarditis.

Electron microscopy of myocardial tissue. A nine year review.

AIM: To review and reassess the role of this department's experience with routine electron microscopy of myocardial tissues. METHODS: A nine year series of myocardial samples that underwent electron microscopy analysis were audited. Fifty nine samples were derived from 46 male and 13 female subjects with an age range of 15-90 years (mean, 50.6). Forty two samples were endomyocardial specimens, with 13 being derived from explanted hearts, and four from necropsies. Two cases were from transplanted hearts. These were all reviewed in a blinded fashion, by all three authors separately, in terms of the myocardium at the ultrastructural level. Subsequently, the interpretations/diagnoses were cross compared with the light microscopy and clinical data results. [figure: see text] RESULTS: Four cases of amyloid were identified; in addition, one case of granulomatous inflammation and one case of basophilic degeneration were seen, although all these had been evident on light microscopy. One case of possible mitochondrial myopathy was found. A total of 18 cases revealed changes of a presumed non-specific type including glycogen, lipid, and mitochondrial accumulations. Varying types of degeneration involving myofibres were seen together with variations in interstitial fibrosis and occasional cytoplasmic inclusions. CONCLUSION: Overall, although interesting, the electron microscopy of myocardial tissue added little to the understanding of the patient's disease, with only one case showing changes not found at light microscopy or with other investigations. Further study might shed light on the "non-specific" ultrastructural findings encountered.

A prospective audit of pacemaker function, implant lifetime, and cause of death in the patient.

AIM: To audit prospectively the reasons for pacemaker implantation, the duration of the pacemaker use, the cause of death, and pacemaker function after removal from the patient. METHODS: Pacemakers were removed at necropsy, or from the bodies of patients awaiting cremation, in three hospitals over a three year period. The cause of death was taken from the results of the necropsy or from the certified cause of death. Demographic data, including the time of implant and reasons for implantation, were checked. The pacemakers were analysed in terms of battery status, program, and output under a standard 470 ohm load. RESULTS: 69 patients were studied. Average age at death was 78 and 80 years for men and women, respectively. The average duration since pacemaker implantation was 46 months. Eleven patients had necropsies, showing that three died from ischaemic heart disease, six from cardiomyopathy, one from an aortic aneurysm, and one from disseminated neoplasia. From the necropsy results and death certificates, the distribution of causes of death in the group as a whole were ischaemic heart disease (21), cardiomyopathy (8), cerebrovascular disease (11), neoplasia (11), chest infection/chronic obstructive airways disease (8), and other causes (10). In all cases the pacemaker box function was within normal limits. CONCLUSIONS: Neither primary nor secondary pacemaker dysfunction was found. The study highlights the impact of arrhythmias in cardiomyopathy, and raises questions about the true role of ischaemic heart disease in these pacemaker requiring patients. The relatively short gap between pacemaker implantation and death requires further study.

Use of fine needle aspiration cytology for investigating lymphadenopathy in HIV positive patients.

The cytological diagnoses of 27 lymph node aspirates were compared with the histological diagnoses or clinical outcome in 23 HIV positive patients. There was agreement between the cytological and histological diagnoses in 14 of the 16 surgically biopsied cases. The clinical outcome in the remaining 11 cases was consistent with the cytodiagnosis. Fine needle aspiration (FNA) is a reliable, minimally traumatic, cost effective method with high specificity. It is suitable for an initial rapid diagnosis in HIV positive patients with lymphadenopathy.

Primary adenocarcinoma in an ileostomy: a late complication of surgery for ulcerative colitis.

In the 1950s the treatment of ulcerative colitis was revolutionized by Brooke by way of a colectomy combined with an eversion ileostomy. This procedure is known to be associated with a number of complications that include skin excoriation, stenosis, intestinal obstruction, retraction or prolapse of the stoma, abscess and fistula formation, and ileitis. However, adenocarcinoma arising in the abnormally placed small intestinal mucosa 20 years or more after the initial operation is being increasingly recognized and reported. This article describes one such case and includes an extensive review of the current world literature on the subject of adenocarcinoma arising as a late complication of operation for ulcerative colitis.

Revision of the 1990 working formulation for cardiac allograft rejection: the Sheffield experience.

OBJECTIVE: To audit the 1990 International Society for Heart and Lung Transplantation cardiac rejection criteria and to evaluate the impact on classification and clinical outcomes of a modification in which grade 2 is abolished and grades 1A and 1B are amalgamated into a single "grade 1." METHODS: 1652 heart biopsies were reviewed over a four year period. The initial 1348 biopsies (group 1), using the original 1990 criteria, were analysed in terms of diagnostic grade and compared with the 304 biopsies analysed with the modified scheme (group 2). Differences in grading with the 1990 scheme were compared between two groups (1.1 and 1.2) reflecting early and late experience with grading. Subsequently all the grade 2 and grade 1B biopsies were rescored in terms of the modified scheme. Clinical results in terms of actuarial patient survival at one year and freedom from 3A rejection were similarly audited. RESULTS: The relative ratios of potentially significant rejection (grade 3A, 3B, 4) remained constant over the entire study in groups 1.1, 1.2, and 2. A 50% reduction in grade 2 biopsy reporting was noted comparing early and late parts of group 1. At subsequent review of the group 1 grade 2 biopsies, 97% could be reassigned to grades 0 or 1 in the modified scheme, with the majority of these diagnoses reflecting Quility effect/biopsy site reactions. Two cases (3%) of the 77 grade 2 biopsies were regraded as grade 3A rejection, with both occurring within three months of transplantation. None of the grade 1B biopsies had high grade cardiac rejection on review, most of these biopsies similarly showing pronounced Quility effect and biopsy site reactions. Actuarial survival at one year rose from 86% to 90% during the study, with freedom from 3A rejection remaining unchanged at 80%. CONCLUSIONS: The original working formulation produces consistent grading except at grade 2, which is judged to be a misnomer resulting from Quility effect and other non-rejection phenomena. While acceptable standardisation can be achieved with the 1990 scheme, the modified scheme has advantages in that it appears to encourage clear discrimination between significant and non-significant cardiac rejection. Overall, elimination of grade 2 did not produce an increase in higher grades of cardiac rejection, and thus the value of this diagnostic grade is questioned.

Plexosarcoma of the bladder.

Plexosarcomas are rare soft tissue sarcomas, previously reported in association with gastrointestinal autonomic nerve (GAN) plexi. We report the first case arising from the autonomic nerve plexus of the bladder.

The nature of the cardiac myxoma.

Ten archive cases of cardiac myxoma were evaluated for proliferative activity, metastatic potential and expression of oncogene/tumor suppressor gene products by means of PCNA, MIB1, nm23, p53, Bcl-2 and Rb-1 immunohistochemistry. The myxomas showed variable proliferative activity (PCNA 0-41%, average 12.6%, MIB1 0-13%, average 3.2%) contrasting with the absence of mitotic activity histologically. All the myxomas showed nm23 staining. None showed p53 reactivity. Eight cases were negative for Bcl-2 expression, with two cases giving weak cytoplasmic staining. Rb-1 reactivity showed a variable pattern (staining indices 0-86%) paralleling the cases' proliferative activity. The cardiac myxoma is interpreted as a weakly proliferative lesion with little metastatic potential and no modulation of oncogene/oncogene suppressor products. Whilst not excluding a neoplastic aetiology, the results are considered more in keeping with a reactive/hamartomatous process.

Inflammatory pseudotumour of the lung mimicking thymoma.

A 36 year old man presented with chest symptoms had a radiological left upper mediastinal lesion, that was interpreted as an anterior mediastinal tumour, consistent with a thymoma. At operation an inflammatory pseudotumour was found in the left upper lobe of the lung, that was projecting across and in front of the mediastinum. The investigation and surgical management of these tumours are reviewed in the light of the presenting symptoms and radiological imaging.

The effect of antihistamine, endothelin antagonist and corticosteroid prophylaxis on contrast media induced bronchospasm.

Bronchospasm is a well recognized adverse reaction to radiographic contrast media (RCM) and may occur more frequently in asthmatics and atopics. This study was designed to identify RCM which are most likely to cause bronchospasm and to investigate underlying mechanisms mediating this response. Guinea pigs (mean body weight 550 g, n = 46) were anaesthetized with Hypnorm (5 ml kg-1) and Hypnovel (2 ml kg-1) and tracheal, jugular and pleural cannulae introduced. Total airways resistance (Raw) was calculated from the slope of the pressure/flow relationship. The effects of RCM (diatrizoate 370 mgI ml-1, ioxaglate 320 mgI ml-1, iotrolan 300 mgI ml-1 and iopromide 300 mgI ml-1) at a dose of 4 ml kg-1 body weight or control solutions matched for volume, pH and osmolarity administered via the jugular vein on Raw were studied. The effects of pre-treatment (30 min before the administration of RCM) with antihistamine (Mepyramine (30 mg kg-1 i.p.)) or non-selective endothelin receptor antagonist (SB209670 (1 mg kg-1 i.v.)) were investigated. The effectiveness of corticosteroids prophylaxis (prednisolone (20 mg kg-1 i.p.)) administered 18-24 h and 1 h pre-RCM was also assessed. Control animals received normal saline pre-treatment before RCM administration. Lungs were taken for histological examination 30-40 min post-administration of RCM. Only ioxaglate caused a significant (p < 0.05) increase in Raw (5.19 +/- 0.58 to 13.95 +/- 3.53 mmHg ml-1 min-1). Neither mannitol nor saline control solutions had any effect on Raw. Pre-treatment with Mepyramine, SB209670 or prednisolone caused no significant change in the ioxaglate induced increase in Raw. Histological examination of lung tissue from ioxaglate treated animals showed no important abnormalities. In summary, only the ionic dimer ioxaglate caused an increase in Raw. This effect was independent of osmolarity and could be the result of the chemical composition of the contrast agent. It was not an inflammatory response and could not be prevented by prophylactic treatment with antihistamine, endothelin antagonist or corticosteroids. The mechanisms responsible for the increase in Raw remain uncertain.

Mucoid cystic degeneration of the cruciate ligament.

A 35-year-old man was seen with pain in the back of the knee. MRI showed a mass in the anterior cruciate ligament. Biopsy indicated mucoid degeneration. Arthroscopic resection of the ligament was carried out, with relief of symptoms.