Structural insights into the interaction between molluscan hemocyanins and phenolic substrates: An in silico study using docking and molecular dynamics.

Hemocyanin is a multimeric type-3 copper containing oxygen carrier protein that exhibits phenoloxidase-like activity and is found in selected species of arthropoda and mollusca. The phenoloxidase activity in the molluscan hemocyanins can be triggered by the proteolytic removal of the C-terminal ß-rich sandwich domain of the protein or by the treatment with chemical agents like SDS, both of which enable active site access to the phenolic substrates. The mechanism by which SDS treatment enhances active site access to the substrates is however not well understood in molluscan hemocyanins. Here, using a combination of in silico molecular dynamics (MD) and docking studies on the crystal structure of Octopus dofleini hemocyanin (PDB code:1JS8), we demonstrate that the C-terminal ß-domain of the protein plays a crucial role in regulating active site access to bulky phenolic substrates. Furthermore, MD simulation of hemocyanin in SDS revealed displacement of ß-domain, enhanced active site access and a resulting increase in binding affinity for substrates. These observations were further validated by enzyme kinetics experiments.

Primary cervical lymphoma: a rare presentation to a genitourinary medicine clinic.

Primary non-Hodgkin's lymphoma of uterine cervix is a rare diagnosis. We present the case of a 47-year-old woman who presented to our genitourinary (GU) medicine service complaining of a malodorous discharge. Speculum examination revealed a necrotic mass on the cervix. She was referred urgently to gynaecology and subsequent histology revealed a diffuse large B-cell lymphoma. She received six cycles of RCHOP chemotherapy and is now in clinical remission. This case highlights the need for GU medicine physicians to remain vigilant with regard to possible gynaecological malignancies in all of our patients, the need for medical backup within GU medicine clinics and for clear pathways of referral to other specialists to exist.

Purification, spectroscopic characterization and o-diphenoloxidase activity of hemocyanin from a freshwater gastropod: Pila globosa.

Hemocyanins are multi-subunit oxygen carrier proteins, found in select species of arthropoda and mollusca. Here, we have purified native hemocyanin from Pila globosa, a freshwater gastropod, verified using mass spectrometry and determined its molecular weight, secondary structure and the spectral properties, using Ultraviolet/visible, Fourier transform infra-red and Circular dichroism spectroscopy. Our results reveal the oligomeric and glycosylated nature of the protein, comprising of 400 kDa subunits, organized predominantly into a thermo-stable, alpha-helical conformation. Further, biochemical assays confirm catecholoxidase-like activity in hemocyanin, which has been used to develop a first-generation optical sensor, for the detection of phenols.

The significance of tumour cell immunophenotype in myeloma and its impact on clinical outcome.

BACKGROUND AND AIMS: Antigen expression of multiple myeloma (MM) cells is heterogeneous. We have investigated the clinical impact of expression of some of the commonly used immunohistochemical markers in the diagnostic work-up of bone marrow trephine biopsy (BMTB) samples in MM. PATIENTS AND METHODS: BMTB samples from 107 MM patients who had received an autologous stem cell transplant (ASCT) following chemotherapy were evaluated. In 75 cases, the immunophenotype had been evaluated on two or more occasions on further follow-up. RESULTS: In the cases evaluated, 32%, 79%, 73%, 39% and 60% of cases had been scored positive for CD20, CD79a, CD56, cyclin D1 and epithelial membrane antigen (EMA) respectively. Absence of CD79a was predictive of poor overall survival (OS) from the time of transplant (p = 0.029) and poor event-free survival (EFS) from the time of transplant (p = 0.003). Absence of EMA (p = 0.02) was predictive of poor EFS from the time of diagnosis. Presence of CD56 was predictive of poor EFS from the time of diagnosis (p = 0.026). On multivariate analysis, only CD79a expression (OS and EFS from the time of transplant) and EMA expression (EFS from the time of diagnosis) maintained their significance. 13 of 75 patients showed an immunophenotypic drift during the disease course. Loss of CD20 (four cases) during the disease course in cases that were previously scored positive correlated with significant worsening both, of OS (p = 0.02) and EFS (p = 0.009) from the time of diagnosis. CONCLUSION: Immunophenotype impacts on clinical outcome in MM.

Immunophenotype of neoplastic plasma cells in AL amyloidosis.

AIM: AL amyloidosis (ALA) is a form of plasma cell (PC) dyscrasia characterised by deposition of insoluble fibrillar deposits in various organs causing organ damage. This is believed to be the first study to evaluate the expression of CD79a, CD20, CD56, cyclin D1 and epithelial membrane antigen (EMA) in neoplastic PCs of ALA. METHODS AND RESULTS: The study included 36 well-documented cases of ALA. In all cases presence of amyloid deposits had been documented by Congo Red stain in the bone marrow trephine biopsy (BMTB) and/or in other tissues. BMTBs showed varying degrees of PC infiltration (median 12%). In eight of the 36 cases with associated myeloma, the mean (2 x SE) percentage of PCs (PC%) was 34 (18)%, while in the remaining, PC% was 15 (4)%. Expression of CD20, CD79a, CD56, cyclin D1 and EMA was noted in 42%, 86%, 50%, 53% and 83% of cases, respectively. Aberrant antigen expression in the form of CD56 and/or cyclin D1 expression was seen in 79% of cases. Nine of 10 cases with small lymphoid-like PCs were positive for CD20 and all the 10 cases were positive for cyclin D1. On the other hand, among cases without small lymphoid-like morphology, CD20 and cyclin D1 expression was seen in only 6 of 26 and 8 of 26 cases respectively (p = 0.001 and 0.002 respectively). CD20 expression correlated with cyclin D1 expression (p = 0.045). Cytological atypia/pleomorphism was predictive of associated myeloma (p = <0.001). CONCLUSION: Marrow involvement by neoplastic PCs in ALA can be identified by their aberrant antigen expression apart from light chain restriction, and rituximab as a possible treatment option may be explored in CD20-positive ALA.

Correlation of cyclin D1 transcript levels, transcript type and protein expression with proliferation and histology among mantle cell lymphoma.

BACKGROUND: Cyclin D1 expression is central to mantle cell lymphoma (MCL) biology. The cyclin D1 gene produces two forms of mRNA: long (D1L) and short (D1S) versions. AIMS: To study the relationship between histology, cyclin D1 mRNA (transcript) levels, cyclin D1 transcript type, cyclin D1 protein expression by immunohistochemistry (IHC), and proliferation (Ki-67%). METHODS: 17 MCLs were initially studied for: levels of expression of cyclin D1 transcripts and for cyclin D1 transcript type by reverse-transcriptase PCR; intensity and percentage cyclin D1 protein expression by IHC; and Ki-67% by IHC. The relationship between cyclin D1 protein expression and proliferation was further validated on an independent set of 23 MCLs. RESULTS: MCLs expressed variable levels of cyclin D1 at both transcript and protein levels. Furthermore, D1L and D1S were the predominant transcripts in 69% and 31% of cases, respectively. While only 9% of cases with dominance of D1L had blastoid histology, 60% of the cases with dominance of the D1S had blastoid features. Furthermore, the levels of D1L showed direct correlation with cyclin D1 protein expression and Ki-67%. Among these cases, and in the independent set of MCLs (n = 40), the level of cyclin D1 protein expression directly correlated with Ki-67%. CONCLUSIONS: MCLs express variable levels of cyclin D1 transcripts and protein, and have variable proliferation (Ki-67%). Cases with dominance of D1S transcripts are more likely to be of blastoid morphology. There is correlation between D1L transcripts levels, cyclin D1 protein expression and Ki-67%.

Nodal marginal zone B-cell lymphoma with prominent follicular colonization - difficulties in diagnosis: a study of 15 cases.

AIMS: While colonization of reactive follicles is well described in mucosa-associated lymphoid tissue lymphoma, this is not fully appreciated in nodal marginal zone B-cell lymphoma (NMZL). The aim was to address how to recognise this feature/entity and to discuss diagnostic difficulties faced by histopathologists in dealing with such lesions and their biological implications. METHODS AND RESULTS: Fifteen NMZLs with prominent follicular colonization are described, 14 of which were referrals from other hospitals. All cases had a follicular pattern and showed prominent 'follicular colonization'. In many follicles the colonization was partial, and follicles also had a reactive germinal centre component. The phenomenon of follicular colonization was highlighted by immunohistochemistry. The benign follicle centre cells expressed CD20, CD10 and Bcl-6 and were negative for Bcl-2 and MUM1. In contrast, the colonizing marginal zone lymphoma cells expressed CD20, Bcl-2 and often MUM1 and were negative for Bcl-6 and CD10. Partially colonized follicles showed a 'moth-eaten' appearance on CD10, Bcl-2, Bcl-6 and MUM1 immunohistochemistry. In none except one was the referring diagnosis NMZL. CONCLUSION: Recognizing and appreciating follicular colonization in a subset of NMZLs, appropriate use of immunohistochemistry and knowledge of immunohistological features can aid in making the correct diagnosis.

The successful treatment of haemophagocytic syndrome in patients with human immunodeficiency virus-associated multi-centric Castleman's disease.

Both virus-associated haemophagocytic syndrome (HPS) and human immunodeficiency virus-associated multi-centric Castleman's disease (HIV-MCD) induced by human herpesvirus-8 (HHV-8) are extremely rare. We therefore wished to investigate their occurrence together, and establish the degree of cytokine activation present. From a prospective cohort of individuals with HIV-MCD, we investigated the incidence and outcomes of HPS and measured 15 inflammatory cytokines and the plasma HHV-8 viral loads before and during follow-up. Of 44 patients with HIV-MCD with an incidence of 4.3/10,000 patient years, four individuals (9%) were diagnosed with HPS. All are in remission (range 6-28 months) following splenectomy, etoposide and rituximab-based therapy. Plasma HHV-8 levels were raised markedly at presentation (median 3,840,000 copies/ml). Histological samples from spleen, splenic hilar lymph nodes and bone marrow demonstrated increased phagocytosis by histiocytes and presence of HHV-8-infected plasmablasts outside the follicles. Surprisingly, many known inflammatory plasma cytokines were not elevated, although interleukin (IL)-8 and interferon-gamma were increased in all cases and IL-6 levels were raised in three of four patients. HPS in the setting of HIV-MCD is common and treatment can be successful provided the diagnosis is made appropriately. Systemic activation of cytokines was limited, suggesting that immunosuppressive therapy with steroids is not indicated in HHV-8-driven HPS.

Bone marrow trephine combined with immunohistochemistry is superior to bone marrow aspirate in follow-up of myeloma patients.

AIMS: Multiple myeloma (MM) guidelines in the UK do not advocate performing bone marrow trephine biopsy (BMTB) during follow-up. In a recent study, it was found that the plasma cell per cent (PC%) in BMTB performed at the time of autologous stem cell transplant strongly correlated with survival. The current study addresses whether BMTB is superior to bone marrow aspiration (BMA) in documenting presence of disease and its volume at follow-up. METHODS: The study involved 106 samples. A conventional 500-cell differential count was performed on the BMAs to document the PC%. The PC% on BMTBs had been estimated on CD138 immunostain. Furthermore, BMTBs had also been immunostained for CD56, cyclin D1 and light chains. RESULTS: The mean (2SEM) PC% values in BMAs and BMTBs were 13.1 (2.6)% and 31.8 (5.8)% respectively. Based on BMA, BMTB and serum/urine paraprotein or light chain estimation, on 92 occasions (89%) there was detectable disease. The positive predictive value of both BMA and BMTB was 100%, and the negative predictive values for BMTB and BMA were 57% and 22% respectively. Among 98 secretory MM cases, the BMTB-PC% showed significant correlation with paraprotein levels, whereas BMA-PC% did not. CONCLUSIONS: It is strongly recommended that BMTB is performed and adequately investigated with immunohistochemistry during follow-up of MM.

Absence of cyclin-D2 and Bcl-2 expression within the germinal centre type of diffuse large B-cell lymphoma identifies a very good prognostic subgroup of patients.

AIMS: To validate and improve the existing algorithm (proposed by Hans et al.) to classify diffuse large B-cell lymphoma (DLBCL). METHODS AND RESULTS: Tissue microarrays constructed from 81 patients with DLBCL were studied by immunohistochemistry for expression of CD10, Bcl-6, MUM1, Bcl-2, cyclin-D2, FOXP1 and PKC-gamma proteins. Cases were classified as either germinal centre B-like (GCB) or non-GC according to Hans et al. An alternative classification was also employed, in which cases positive for either CD10 or Bcl-6 were considered as a GC subgroup and cases negative for both CD10 and Bcl-6 were considered as a non-GC subgroup. GC was further subdivided into favourable GC (negative for both Bcl-2 and cyclin-D2) and unfavourable GC (positive for either Bcl-2 or cyclin-D2). The 5-year event-free survival (EFS) amongst patients classified as favourable GC versus 'others' was 49.5% and 7.3%, respectively (log rank P < 0.0001). Similarly, the 5-year overall survival (OS) amongst patients classified as favourable GC versus 'others' was 58.6% and 13.7%, respectively (log rank P = 0.0001). The difference in survival was independent of the international prognostic index. CONCLUSIONS: In this group of patients the risk stratification based on the new algorithm was better than that proposed by Hans et al.

Optimal processing of bone marrow trephine biopsy: the Hammersmith Protocol.

Specimens of bone marrow trephine biopsy (BMT) are transported and fixed in acetic acid-zinc-formalin fixative, decalcified in 10% formic acid-5% formaldehyde and processed with other specimens to paraffin-wax embedding. Sections, 1-microm-thick, are cut by experienced histotechnologists and used for haematoxylin and eosin, Giemsa, reticulin silver and other histological stains. Further, all immunohistochemical procedures used in the laboratory, including double immunostaining, can be used on these sections with no or minimal modifications. About 10,000 BMT specimens have been analysed using this procedure since 1997 and diseases involving the bone marrow have been classified successfully. More recently, standardised polymerase chain reaction-based analysis and mRNA in situ hybridisation studies have been conducted. Excellent morphology with good antigen, DNA and RNA preservation is offered by the Hammersmith Protocol.

Report of an International Network of Cancer Treatment and Research workshop on non-Hodgkin's lymphoma in developing countries.

The International Network of Cancer Treatment and Research (INCTR) recently organized a workshop on non-Hodgkin lymphomas (NHLs) in selected developing countries with the purpose of examining existing information relating to the pathology and management of these neoplasms, and identifying potential areas for research. This report provides a summary of the information presented and is focused primarily on the pathology of NHLs in children and adults. In most countries, the WHO classification of lymphomas was used and most participating centers included immunohistochemistry using a wide array of lymphoid antibodies as part of routine diagnosis. Some of the series had been reviewed by an external panel of experts. B-cell lymphomas accounted for 82-88% of all NHLs. The proportions of chronic lymphatic leukemia (4-6%), mantle cell lymphoma (MCL, 3-5%), and plasmacytoma (2-4%) were similar in the series presented. However, there was a significant variation in the proportion of follicular lymphoma (FL), which accounted for 15% and 11% in India and Kuwait, but less than 5% in Pakistan and Egypt. All of these frequencies are significantly lower than those reported in Western series. Diffuse large B-cell lymphoma accounted for about 35% of cases in India but for more 50% in other countries, but this difference was not accounted for by an increased incidence in a single lymphoma subtype in India, but rather an apparent paucity of several subtypes (such as mantle cell and marginal zone lymphomas (MZL)) in other series. There were relatively high frequencies of Burkitt lymphoma in Egypt (7%) and precursor T-cell lymphoblastic lymphoma in India (6-7%). Peripheral T-cell lymphomas (PTCLs) (not otherwise specified and angioimmunoblastic subtypes) accounted for 3-5% of NHLs, and extranodal lymphoma of T/NK cell type was rare (<1%). These differences in the relative proportions of NHL subtypes among developing countries and between developing countries and the rest of the world presumably arise from differences in environmental and genetic factors that influence lymphomagenesis and strongly suggest that more research in developing countries would provide valuable insights into the pathogenesis of lymphoid neoplasms.