Multimodal image analysis of chronic leukemic lymphoproliferative disorders and the hypothesis of "single" and "multiple" programmed stops in the development of typical and atypical forms of leukemias and lymphomas

The study consisted of morphometric analysis, assessment of the argyrophilic nucleolar organization region (AgNOR) characteristics, and image cytometry (ICM) in different tumor mass compartments: bone marrow (BM), peripheral blood (PB) and lymph nodes (LN) from patients with chronic leukemic lymphoproliferative disorders. A total of 71895 cells were analyzed on SFORM PC (VAMSTEC, Zagreb). Correlation between morphometric, AgNOR and ICM characteristics revealed the cells with low proliferative activity to possess small, homogeneous AgNOR, with the majority of cells in the peak of DNA histogram. The cells with high proliferative activity had inhomogeneous AgNOR, mostly containing greater DNA content than peak cells, pathologic mitoses (DNA > 4N), or the majority of cells were in the S-phase of the cell cycle. Cells with medium proliferative activity and annular AgNOR were in-between. Analysis of different tumor mass compartments showed that lymphatic cells with the affinity to accumulate in BM regularly exhibited low proliferative activity (a lower percentage of cells in SFC and highest percentage of cells in the peak of the G0/G1 phase). The cells in LN exhibited the characteristics of proliferative cells (an increased number of AgNOR, larger and more proliferative inhomogeneous AgNOR, and lowest percentage of cells in the G0/G1 phase). The migration of cells from BM to LN and between lymph nodes occurred through PB (there were cells with low and high proliferative activity: a higher proportion of cells in SFC and at the same time in the G0/G1 phase of the cell cycle). Analysis of cell size and proliferative activity in different compartments of tumor mass revealed that the cells in BM and PB did not differ substantially according to size and proliferative activity, while an inverse pattern was observed between PB and LN. As small cells are inactive and larger cells more proliferative, the analysis quite unexpectedly showed the PB cells to be largest and most inactive, in contrast to LN where the cells were smallest and most active. The "single" and "multiple programmed stops" have been hypothesized in the development of typical forms of leukemias and lymphomas and atypical forms of subacute and subchronic leukemias. Differentiation impairment may occur at any stage, and different "stop" locations result in different morphology and affinity to accumulation in bone marrow, peripheral blood and lymph nodes.

Flow cytometric analysis of deep-seated lymph nodes

Flow cytometry (FC) immunophenotyping is an important tool in the evaluation of lymphadenopathy and is widely used in the diagnosis of non-Hodgkin's lymphomas (NHLs) on fine-needle aspirates of lymph nodes and extranodal sites. Because at least 80% of NHLs are of B-cell type, detection of immunoglobulin (Ig) light-chain-restriction is the most commonly used method for confirmation of monoclonality. The aim of our study was to evaluate usefulness of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for FC analysis from deep-seated lymph nodes and to compare results of FC clonality analysis to cytomorphologic diagnosis of sampled lymph nodes. For cytological diagnosis direct smears were made, selected slide was stained for rapid-on site evaluation procedure. Sixteen patients with suspected NHL of deep-seated lymph nodes obtained by EUS-FNA were submitted for FC clonality analysis using four-color multiparameter flow cytometry stained with kappa/lambda/CD19/CD45. Clonality analysis was performed on 11 samples. Monoclonality was demonstrated in seven of 11 cases cytologically diagnosed as NHL and four of 11 cases cytologically diagnosed as benign were polyclonal. Our results show that EUS-FNAC with FC is a sensitive and specific tool in the diagnosis of deep-seated B-NHL. Cytologic diagnosis combined with FC clonality analysis can be performed in majority of cases and may eliminate need for open biopsy in some cases.

Detection of t(14;18) by PCR of IgH/BCL2 fusion gene in follicular lymphoma from archived cytological smears

According to WHO classification follicular lymphoma (FL) is a neoplasm composed of follicle centre (germinal centre) B-cells, which usually has at least a partially follicular pattern. Bone marrow (BM) infiltration by lymphoma occurs in 40-70% of cases at the time of diagnosis. The characteristic chromosomal translocation of follicular lymphoma is t(14;18)(q32;q21) with transposition of BCL2 oncogene to the regulatory region of immunoglobulin heavy chain gene IgH. Aim of this study was to determine the frequency of PCR detection of IgH/BCL2 in DNA samples isolated from archival cytological slides of lymph node aspirates, bone marrow and/or peripheral blood (PB) obtained from patients with histologically confirmed follicular lymphoma using primers and protocol proposed by BIOMED-2 consortium. We also compared molecular with cytomorphological findings in bone marrow/peripheral blood and tested this method of detection of IgH/BCL2 molecular marker in monitoring minimal residual disease (MRD) in routine clinical setting. DNA was successfully isolated from all archival cytological slides obtained by fine needle aspiration of lymph nodes as well as from 75% of smears of bone marrow aspirates from 19 patients. Fusion oncogene was detected in 10 of 19 patients (52%). For patients with PCR IgH/BCL2 positive lymph nodes, molecular test found BM infiltration in 5 cases (83%), while cytomorphology detected infiltration in three of eight cases (37%) available for comparison. May-Grünwald-Giemsa stained cytological smears can be used for PCR-based ancillary methods and the rate of detection of IgH/BCL2 rearrangement is similar to results reported for paraffin-embedded tissues. For patients with detectable baseline molecular marker, PCR is a highly suitable method for detection of bone marrow involvement and monitoring MRD.

The accuracy of fine needle aspiration cytology and flow cytometry in evaluation of nodal and extranodal sites in patients with suspicion of lymphoma

Today lymphomas are defined according to a combination of morphology, immunophenotype, genetic features and clinical presentation, so beside the pure cytomorphologic analysis in diagnosis of lymphoma ancillary techniques such as cytochemistry, immunocytochemistry, molecular diagnosis and flow cytometry (FC) are often used. Our goal was to determinate how is information given by fine-needle aspiration cytology (FNAC) and FC correlated with pathohistologic diagnosis and to evaluate ability to diagnose and subclassify malignant lymphomas by FNAC and FC. This study is a retrospective chart review of patients with suspicion of lymphoma processed at University Hospital Dubrava in Zagreb. After analysis 50 patients fulfilled inclusion criteria for this study (FNAC diagnosis with or without FC and consecutive confirmatory pathohistological diagnosis). When analyzing accuracy of FNAC according to suspicion of lymphoma or NHL and differential diagnosis lymphoma sensitivity was 97.7%, specificity 85.7% and the diagnostic accuracy was 96%. When analyzing accuracy of FNAC according to the subclassification of lymphoma, sensitivity was 74.4%, specificity 85.7% and the diagnostic accuracy 76%. Combined FNAC and FC improved sensitivity, positive predictive value, negative predictive value and diagnostic accuracy. Sensitivity was 79.1% and the diagnostic accuracy 80%. We have shown that these methods can distinguish benign lymphadenopaties from lymphomas and also subclassify lymphomas and quickly provide clinicians with that information.

Chronic lymphocytic leukemia: insights from lymph nodes & bone marrow and clinical perspectives

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by highly variable distribution of tumor mass between peripheral blood, bone marrow and lymphoid organs which is important for staging, classification and prognosis. These clinical findings with novel data about importance of B-cell receptor and its stimulation with the support of microenvironment indicate important role of tissues (lymphoid organs and bone marrow) in the pathogenesis of B-CLL. Here is presented the novel approach of simultaneous characterization of B-CLL cells form peripheral blood, bone marrow and lymph nodes by flow cytometry and immunocytochemistry, defining inter- and intraclonal diversity with respect to various molecules. These include adhesion molecules (integrins, immunoglobulins, selectins), chemokine receptors (including CXCR-4), signaling molecules and prognostic factors (CD38 and ZAP-70), proliferation and apoptosis markers (including Ki67, AgNORs with PK index, survivin, bcl-2) and therapeutic targets (CD20 and CD52) and residual hematopoietic stem cells. A number of interesting significant interactions have been discovered, pointing to the important role of neoplastic cell microenvironment. These may in addition to insights in pathogenesis and roles of different microenvironments add to diagnosis, prognosis and treatment of B-CLL patients.

Monocytes in metabolic disorders--opportunities for flow cytometry contributions

Chronic inflammation has arised as a major underlying cause of atherosclerosis, obesity and diabetes. It is mediated by cells of innate immune system like macrophages but also by their antecedents, circulating monocytes. Roles of monocyte subsets and different markers of monocyte activation in the context of metabolic disorders have been reviewed. Applying cell based approach through flow cytometry in this field has resulted with new understanding of pathophysiologic mechanisms. Possible implications of these insights in diagnosis, prognosis and revealing of therapeutic targets in metabolic disorders remain a challenge for future.

The utilization of antibiotics in the management of acute pancreatitis--experience from one transitional country university hospital

The aim of the study was to analyze the evidence-based use of antibiotic therapy in the treatment of acute pancreatitis and to identify factors influencing the introduction of antibiotic therapy in the setting of transitional country clinical hospital. This retrospective study was conducted at Department of Internal Medicine at University Hospital Dubrava in Zagreb, Croatia. Data were collected from hospital records of patients treated for acute pancreatitis from January 1st, 2005 till December 31st, 2005. Data collected from patients' histories were compared with indications for antibiotic treatment and antibiotics with demonstrated therapeutic efficacy in acute pancreatitis which were obtained from published literature. Logistic regression was used to identify factors with a significant impact on deciding on the introduction of antibiotic therapy, and multivariate analysis was used to identify factors with a significant impact on the cost of treatment. Statistical significance was set at p < 0.05. Antibiotic therapy was used in 67.7% of patients with acute pancreatitis. Combination of amoxicillin plus clavulanic acid was most frequently administered, either as monotherapy or in combination with metronidazole and/or gentamicin (37.3%), followed by cefuroxime (32.8%) and cefoperazone (26.9%). The choice of antibiotic was appropriate in 35.8% of study patients; however in 29.9% of patients who were administered antibiotics had no indication for this therapy; and 46.9% of patients who had indications for receiving antibiotic therapy didn't receive it. In the groups of patients treated with antibiotics, the cost of treatment was significantly higher compared to groups of patients who were not treated with antibiotics (p = 0.0035; p = 0.0026). In addition to antibiotic therapy, the cost of treatment was significantly influenced by the length of hospital stay and treatment at intensive care unit. The use of antibiotics in the setting of transitional country university hospital in patients with acute pancreatitis is not evidence-based. Decision on the introduction of antibiotic therapy is not based on objective parameters of disease severity or evidence of therapeutic efficacy of particular antibiotics. The cost of treatment is significantly increased by the use of antibiotic therapy.

Prevalence and clinical significance of left atrial spontaneous echo contrast detected by transesophageal echocardiography

The prevalence and clinical significance of left atrial spontaneous echo contrast (SEC) were studied in patients undergoing transesophageal echocardiography (TEE). The study group included 290 consecutive patients (186 male and 104 female, aged 17-86 years, mean age 56.1 +/- 12.8 years). Left atrial SEC was found in 50 (17.2%) patients, and was significantly associated with atrial fibrillation, mitral stenosis, absence of mitral regurgitation, and left atrial dimension. Atrial fibrillation was recorded in 44 (88%) patients, mitral stenosis or mitral valve replacement in 21 (42%) patients, and left atrial thrombus or previous embolism in 23 (46%) patients with SEC. Univariate analysis showed a significant association between the presence of SEC and atrial fibrillation, mitral stenosis or mitral valve replacement, and left atrial size. Multivariate analysis showed the presence of left atrial SEC and atrial fibrillation to be independent factors for thrombus formation and/or thromboembolism. Since left atrial SEC associated with atrial fibrillation, left atrial enlargement, mitral stenosis, or mitral valve prosthesis was found in 17.2% of patients undergoing TEE, it might be considered a marker of left atrial thrombus or previous thromboembolism.

Endothelin mediates phospholipase C stimulation in the proximal tubule during initiation of compensatory renal growth in adult rats

AIM

Mechanisms that initiate compensatory renal growth following unilateral nephrectomy are incompletely understood. An early event following unilateral nephrectomy is the activation of phospholipase C in the apical membrane of the proximal tubule, mediated by an unknown agonist. We tested the hypothesis that endothelin is responsible for the stimulation of phospholipase C in rat proximal tubule following unilateral nephrectomy.

METHODS

Compensatory renal growth was induced in adult male rats by unilateral nephrectomy. 1,2-Diacylglycerol, a product of phospholipase C activation, was measured in renal cortical slices and isolated proximal tubules, respectively, 20 min following unilateral nephrectomy, or after incubation of the slices or proximal tubules with plasma from unilaterally nephrectomized or sham-operated rats.

RESULTS

Twenty min following unilateral nephrectomy, an increase in 1,2-diacylglycerol concentration occurred in the renal cortex. Bosentan, a nonselective endothelin receptor antagonist, as well as an anti-endothelin-1 antibody administered intravenously, completely inhibited this 1,2-diacylglycerol accumulation in renal cortex. Incubation of renal cortical slices with plasma from unilaterally nephrectomized or bilaterally nephrectomized rats, stimulated 1,2-diacylglycerol production in isolated proximal tubule apical membranes. Again, bosentan prevented the increase evoked by incubation with plasma from unilaterally nephrectomized rats. Finally, concentration of endothelin-1 increased in renal cortex in response to unilateral nephrectomy.

CONCLUSION

These results make evident the role of endothelin in stimulation of phospholipase C in proximal tubule following unilateral nephrectomy, suggesting participation of the endothelin system during the initiation of the compensatory renal growth.

The effect of big endothelin-1 in the proximal tubule of the rat kidney

1. An obligatory step in the biosynthesis of endothelin-1 (ET-1) is the conversion of its inactive precursor, big ET-1, into the mature form by the action of specific, phosphoramidon-sensitive, endothelin converting enzyme(s) (ECE). Disparate effects of big ET-1 and ET-1 on renal tubule function suggest that big ET-1 might directly influence renal tubule function. Therefore, the role of the enzymatic conversion of big ET-1 into ET-1 in eliciting the functional response (generation of 1,2-diacylglycerol) to big ET-1 was studied in the rat proximal tubules. 2. In renal cortical slices incubated with big ET-1, pretreatment with phosphoramidon (an ECE inhibitor) reduced tissue immunoreactive ET-1 to a level similar to that of cortical tissue not exposed to big ET-1. This confirms the presence and effectiveness of ECE inhibition by phosphoramidon. 3. In freshly isolated proximal tubule cells, big ET-1 stimulated the generation of 1,2-diacylglycerol (DAG) in a time- and dose-dependent manner. Neither phosphoramidon nor chymostatin, a chymase inhibitor, influenced the generation of DAG evoked by big ET-1. 4. Big ET-1-dependent synthesis of DAG was found in the brush-border membrane. It was unaffected by BQ123, an ETA receptor antagonist, but was blocked by bosentan, an ETA.B-nonselective endothelin receptor antagonist. 5. These results suggest that the proximal tubule is a site for the direct effect of big ET-1 in the rat kidney. The effect of big ET-1 is confined to the brush-border membrane of the proximal tubule, which may be the site of big ET-1 sensitive receptors.

Different endothelin receptor subtypes are involved in phospholipid signalling in the proximal tubule of rat kidney

Phospholipid signalling mediated by endothelin (ET) receptor subtypes was studied in the rat proximal tubule. In freshly isolated proximal tubule cells, ET-1, ET-2 and sarafotoxin S6c (S6c) evoked an increase in 1,2-diacylglycerol (DAG), inositol 1,4,5-trisphosphate (InsP3) and phosphocholine (PCho), suggesting stimulation of both phosphatidyl-inositol 4,5-bisphosphate- and phosphatidyl-choline-specific phospholipase C (PLC), while ET-3 increased only DAG and PCho, presumably via phosphatidyl-choline-dependent PLC. Renal cortical slices were also stimulated by the above-mentioned agonists, followed by isolation of either brush border (BBM) or basolateral (BLM) membranes for which mass measurements of inositol lipids and DAG were performed. In BBM, DAG increased in response to ET-1, ET-2 and ET-3, and was followed by protein kinase C (PKC) translocation to the BBM, while in BLM, DAG formation and translocation of PKC were observed only in response to ET-3, suggesting spatial segregation of signalling systems between two membane domains of proximal tubule cells. Tyrphostine, pertussis toxin (PTX) or cholera toxin (CTX) did not influence ET-mediated signalling in either of the membranes, suggesting involvement of PTX- and CTX-insensitive G-protein-mediated stimulation of PLCbeta by ET receptors. ET-dependent stimulation of PLC in BBM and BLM was used as a tool to examine the presence of different ET receptor subtypes in these two cell membrane domains. BQ123, an inhibitor of ETA receptors, did not prevent ET-1-mediated signalling in BBM, but an ETA,B antagonist, bosentan, inhibited ET-3-mediated signalling in BBM. In addition, an ETB agonist, S6c, stimulated PLC in BBM. Neither BQ123 nor bosentan inhibited ET-3 signalling in BLM. Therefore, these data strongly suggest the presence of ETB receptors coupled to phosphatidyl-inositol 4,5-bisphosphate- and phosphatidyl-choline-dependent PLC in BBM and ETC receptors linked to phosphatidyl-choline-dependent PLC in BLM.