Intra-crystalline protein diagenesis (IcPD) in Patella vulgata. Part I: Isolation and testing of the closed system.

This study successfully isolates a fraction of intra-crystalline proteins from shells of the marine gastropod Patella vulgata and assesses the suitability of these proteins for IcPD (Intra-crystalline Protein Diagenesis) geochronology. We discuss the mineralogical composition of this gastropod, investigated for the first time by X-ray diffraction mapping, and use the results to inform our sampling strategy. The potential of the calcitic rim and of a bulk sample (containing both apex and rim) of the shell to act as stable repositories for the intra-crystalline proteins during diagenesis is examined. The composition and the diagenetic behaviour of the intra-crystalline proteins isolated from different locations within the shell are compared, highlighting the necessity of targeting consistent sampling positions. We induced artificial diagenesis of both intra-crystalline and whole-shell proteins by conducting high-temperature experiments in hydrous environment; this allowed us to quantify the loss of amino acids by leaching and therefore evaluate the open- or closed-system behaviour of the different fractions of proteins. The results obtained provide further confirmation that patterns of diagenesis vary according to the protein sequence, structure, and location within or outside the intra-crystalline fraction. As Patella is frequently found in the fossil record, both in archaeological and geological contexts, the application of IcPD geochronology to this biomineral opens up the possibility to obtain reliable age information from a range of sites in different areas of the world.

Interactions of native and non-native lady beetle species (Coleoptera: Coccinellidae) with aphid-tending ants in laboratory arenas.

Interactions between lady beetles and the European fire ant (Myrmica rubra L.) tending potato aphids [Macrosiphum euphorbiae (Thomas)] were compared in the laboratory. Lady beetle species native to North America (Coccinella trifasciata perplexa Mulsant, Coleomegilla maculata lengi Timberlake, Hippodamia convergens Guérin-Méneville) and non-native species of Palearctic origin [Coccinella septempunctata L., Harmonia axyridis (Pallas), Hippodamia variegata (Goeze), Propylea quatuordecimpunctata L.)] were evaluated. Harmonia axyridis consumed a significantly greater number of aphids compared with all other species but C. septempunctata. Ant stings affected H. variegata and C. septempunctata to a greater extent than other species. Ants showed a significantly greater amount of aggression toward H. convergens and H. variegata compared with P. quatuordecimpunctata. P. quatuordecimpunctata, C. trifasciata, and H. axyridis reacted significantly less to ants compared with H. variegata, H. convergens, C. maculata, and C. septempunctata. Differences in interactions with natural enemies may explain, in part, the successful establishment of some non-native coccinellids in new habitats.

Mechanised one-day fat clearance method to increase the lymph node yield in rectal cancer specimens.

The Royal College of Pathologists' guidelines for reporting colorectal cancer state that all lymph nodes in a colorectal cancer specimen should be sampled, regardless of site or size. The only means by which one can be certain that all nodes have been sampled is to clear the fat and visualise the lymph nodes. Methods of fat clearance have been available for many years, but few are acceptable in routine practice. Here, a simple, effective and economical solution to the problem is described, which should be amenable to any laboratory with a spare or back-up tissue-processing machine.

Routine transferrin saturation measurement in liver clinic patients increases detection of hereditary haemochromatosis.

BACKGROUND: Hereditary haemochromatosis (HH) is one of the commonest genetic disorders in European populations. Transferrin saturation (TFS) measurement has been advocated as a phenotypic screening test to improve detection. We undertook a prospective study to examine the value of routine TFS measurement in detecting new cases of HH in unselected liver clinic attenders. METHODS: Non-fasting TFS was measured in new patients. HH mutations were determined in those with elevated TFS (>45%) and all who underwent liver biopsy. Liver biopsy was performed in 349 patients, including all found to be C282Y homozygotes or compound heterozygotes. RESULTS: Of 667 new patients attending over 5 years, 156 had TFS >45% and 18 had significant mutations (12 C282Y homozygotes and six compound heterozygotes). Eleven of the 12 C282Y homozygotes identified had an elevated TFS and 10 had significant hepatic siderosis. Only two of the six compound heterozygotes had an elevated TFS and hepatic siderosis. CONCLUSIONS: The prevalence of new HH cases in patients of European origin attending a liver clinic, detected by phenotypic screening over a 5-year period, was 2.8%. All were identified by a TFS cut off >45%, but TFS >60% provided the best combination of sensitivity and specificity for detecting C282Y homozygosity.

Low frequency of somatic mutations in the FH/multiple cutaneous leiomyomatosis gene in sporadic leiomyosarcomas and uterine leiomyomas.

Germline mutations in the fumarate hydratase gene at 1q43 predispose to dominantly inherited skin and uterine leiomyomata and leiomyosarcomas. The enzyme, which is a component of the tricarboxylic acid cycle, acts as a tumour suppressor. To evaluate fumarate hydratase in respective sporadic tumours, we analysed a series of 26 leiomyosarcomas and 129 uterine leiomyomas (from 21 patients) for somatic mutations in fumarate hydratase and allelic imbalance around 1q43. None of the 26 leiomyosarcomas harboured somatic mutations in fumarate hydratase. Fifty per cent of leiomysarcomas tested showed evidence of allelic imbalance at 1q, but this was not confined to the vicinity of fumarate hydratase. Only 5% (seven out of 129) of the leiomyomas showed allele imbalance at 1q42-q43 and no somatic mutations in fumarate hydratase were observed. Our findings indicate that mutations in fumarate hydratase do not play a major role in the development of sporadic leiomyosarcomas or uterine leiomyomas

A lack of evidence for down-modulation of CD3 zeta expression in colorectal carcinoma and pregnancy using multiple detection methods.

Loss of the T cell receptor-associated CD3 zeta chain has been proposed as a possible mechanism of the acquired immunosuppression in both tumour-bearing hosts, and in symptomatic patients with HIV infection. However, other reports suggest that the zeta-chain loss may in part be caused by protease activity of contaminating phagocytes ex vivo. Using flow cytometry and Western blot analysis on highly purified T cells, and ensuring adequate addition of protease inhibitors, we have studied the expression of CD3zeta on peripheral blood T cells from patients with colorectal carcinoma, and compared these with normal controls, and pregnant donors, as a further example of an immunocompromised state. Immunohistochemistry was performed on tumour sections from patients with colorectal carcinoma to measure CD3zeta expression in tumour infiltrating T cells, and compared with normal mucosa and tonsil. Using these three approaches, our data provide no evidence for downregulation of CD3zeta chain expression either in colorectal carcinoma or pregnancy and suggest that this explanation is unlikely to fully account for the reduced T cell function associated with these conditions in all patients.

Kaposi's sarcoma masquerading as pyogenic granuloma of the nasal mucosa.

Kaposi's sarcoma (KS) is a neoplastic vascular disorder characterized by multiple reddish blue nodules which, according to the original description (Kaposi, 1872), usually present on the skin of the upper and lower extremities. It is not until the disease progresses that nodules appear on the skin of the head and neck, on mucosal membranes and as visceral lesions. However, with the large increase in the incidence of this tumour associated with the acquired immune deficiency syndrome (AIDS) epidemic, there have been increasing numbers of cases of Kaposi's sarcoma presenting primarily on the skin or mucosa of the head and neck. The most common sites reported are within the oral cavity, particularly on the palate. Other mucosal sites are rare. We present an unusual case where the primary manifestation of the Kaposi's sarcoma was in the nasal mucosa and stress the importance of this diagnosis not being overlooked.

T-cell lymphoma in Hashimoto's thyroiditis.

An elderly Caucasian woman with a 2-year-history of hypothyroidism, treated with thyroxine, presented with a rapidly growing mass in the thyroid. The morphological and immunological features of this thyroid tumour were those of a peripheral T-cell lymphoma with an immunophenotype commonly associated with HTLV-1 positive-adult T-cell leukaemia/lymphoma, although serology for HTLV1 antibody was negative. Monoclonal gene rearrangements were demonstrated with T-cell receptor beta- and gamma-specific primers. There are several interesting features in this case (i): although primary B-cell lymphomas (MALT-associated lymphomas) of thyroid are a well-recognized sequel to thyroiditis, primary T-cell lymphomas are rare, even in areas of the world where adult T-cell lymphomas predominate; (ii) the tumour showed the typical immunophenotype of an HTLV-1 positive T-cell lymphoma but the patient is English, has not visited endemic areas, and is serologically negative for HTLV-1; (iii) the residual thyroid gland showed a florid lymphocytic thyroiditis with Hürthle cell change, typical of Hashimoto's thyroiditis; (iv) unlike other reports of thyroid T-cell lymphoma, which have presented with stage III-IV disease, this tumour presented in the favourable clinical stage of IE.

Quantification of inflammatory bowel disease activity using technetium-99m HMPAO labelled leucocyte single photon emission computerised tomography (SPECT).

Technetium-99m HMPAO labelled white cell bowel uptake was quantified in 23 patients with suspected colitis by means of the novel technique of single photon emission computerised tomography (SPECT) using a standard gamma-camera. Uptake in colon segments was quantified on transaxial images and expressed as a fraction of marrow uptake (SPECT score). Segmental histological disease activity was assessed at colonoscopy (20) or at surgery (3). Segmental histology score correlated with SPECT score r = 0.79 (p < 0.001). Overall SPECT score for all affected segments correlated with Crohn's disease activity index (CDAI) r = 0.66, p = 0.001 and with laboratory activity indices; erythrocyte sedimentation rate r = 0.44, p = 0.03, C reactive protein r = 0.38, p = 0.05, and albumin r = -0.46, p = 0.03. Small bowel SPECT score in 13 patients correlated with CDAI r = 0.65, p < 0.01 but not with erythrocyte sedimentation rate or C reactive protein. Five patients with positive small bowel white cell uptake had normal C reactive protein and erythrocyte sedimentation rate. Overall SPECT score for disease at all sites correlated with both CDAI and with laboratory indices of inflammation. 99mTc HMPAO SPECT provides non-invasive and accurate quantification of inflammatory bowel disease activity in both large and small bowel and may be useful in the objective evaluation of treatment for inflammatory bowel disease.