PRIMARY HYPERPARATHYROIDISM DETECTED BY PARATHYROID INCIDENTALOMA: CLINICAL FEATURES, WORK-UP AND MANAGEMENT.

CONTEXT: With the widespread use of neck ultrasound, parathyroid incidentaloma (PI) emerges as an additional opportunity for incidental detection of primary hyperparathyroidism (PHPT). OBJECTIVE AND DESIGN: This study aimed to investigate PHPT cases detected by PI and to compare them with other PHPT patients. A retrospective analysis of newly diagnosed PHPT patients between 2014 and 2020 was conducted in our hospital. SUBJECTS AND METHODS: The cohort of 124 subjects was divided in two groups: 22 (17.7%) PHPT patients detected by PI (PI PHPT group) and the rest of 102 PHPT patients (non-PI PHPT group). Overall, 21 PIs were discovered on ultrasound and one was found during thyroid surgery. Clinical features, work-up and management of two study groups were compared. RESULTS: The PI PHPT group had lower ionized calcium at diagnosis (p=0.034), lower peak serum calcium during follow-up (p<0.01), less fractures (p=0.022) and was less likely to meet the international criteria for parathyroidectomy (p<0.01). Positive sestamibi scan (p=0.022) and confirmed concordant localization in at least two different parathyroid imaging techniques (p=0.033) were more likely in the PI PHPT group. The frequency of surgical management did not differ between groups. CONCLUSIONS: PHPT detected by PI is clinically relevant and mostly comparable to PHPT in other patients with some features that correspond more often to a mild disease. Higher rate of positive preoperative localization in PHPT detected by PI might encourage parathyroidectomy even without the international criteria met.

Autologous haematopoietic stem cell mobilisation in multiple myeloma and lymphoma patients: a position statement from the European Group for Blood and Marrow Transplantation.

Autologous haematopoietic SCT with PBSCs is regularly used to restore BM function in patients with multiple myeloma or lymphoma after myeloablative chemotherapy. Twenty-eight experts from the European Group for Blood and Marrow Transplantation developed a position statement on the best approaches to mobilising PBSCs and on possibilities of optimising graft yields in patients who mobilise poorly. Choosing the appropriate mobilisation regimen, based on patients' disease stage and condition, and optimising the apheresis protocol can improve mobilisation outcomes. Several factors may influence mobilisation outcomes, including older age, a more advanced disease stage, the type of prior chemotherapy (e.g., fludarabine or melphalan), prior irradiation or a higher number of prior treatment lines. The most robust predictive factor for poor PBSC collection is the CD34(+) cell count in PB before apheresis. Determination of the CD34(+) cell count in PB before apheresis helps to identify patients at risk of poor PBSC collection and allows pre-emptive intervention to rescue mobilisation in these patients. Such a proactive approach might help to overcome deficiencies in stem cell mobilisation and offers a rationale for the use of novel mobilisation agents.

Functional impact of NOTCH1 mutations in chronic lymphocytic leukemia.

The purpose of this study was to compare the expression and function of NOTCH1 in chronic lymphocytic leukemia (CLL) patients harboring a wild-type (WT) or mutated NOTCH1 gene. NOTCH1 mRNA and surface protein expression levels were independent of the NOTCH1 gene mutational status, consistent with the requirement for NOTCH1 signaling in this leukemia. However, compared with NOTCH1-WT CLL, mutated cases displayed biochemical and transcriptional evidence of an intense activation of the NOTCH1 pathway. In vivo, expression and activation of NOTCH1 was highest in CLL cells from the lymph nodes as confirmed by immunohistochemistry. In vitro, the NOTCH1 pathway was rapidly downregulated, suggesting that signaling relies upon micro-environmental interactions even in NOTCH1-mutated cases. Accordingly, co-culture of Jagged1(+) (the NOTCH1 ligand) nurse-like cells with autologous CLL cells sustained NOTCH1 activity over time and mediated CLL survival and resistance against pro-apoptotic stimuli, both abrogated when NOTCH1 signaling was pharmacologically switched off. Together, these results show that NOTCH1 mutations have stabilizing effects on the NOTCH1 pathway in CLL. Furthermore, micro-environmental interactions appear critical in activating the NOTCH1 pathway both in WT and mutated patients. Finally, NOTCH1 signals may create conditions that favor drug resistance, thus making NOTCH1 a potential molecular target in CLL.

European data on stem cell mobilization with plerixafor in non-Hodgkin's lymphoma, Hodgkin's lymphoma and multiple myeloma patients. A subgroup analysis of the European Consortium of stem cell mobilization.

The effectiveness of the novel hematopoietic stem cell mobilizing agent plerixafor was evaluated in nationwide compassionate use programs in 13 European countries. A total of 580 poor mobilizers with non-Hodgkin's lymphoma (NHL), Hodgkin's lymphoma (HL) and multiple myeloma (MM) were enrolled. All patients received plerixafor plus granulocyte CSF with or without chemotherapy. Overall, the collection yield was significantly higher in MM patients (>2.0 × 10(6) CD34+ cells/kg: 81.6%; >5.0 × 10(6) CD34+ cells/kg: 32.0%) than in NHL patients (>2.0 × 10(6) CD34+ cells/kg: 64.8%; >5.0 × 10(6) CD34+ cells/kg: 12.6%; P<0.0001) and also significantly higher in HL patients (>2.0 × 10(6) CD34+ cells/kg: 81.5%; >5.0 × 10(6) CD34+ cells/kg: 22.2%) than in NHL patients (P=0.013). In a subgroup analysis, there were no significant differences in mobilization success comparing patients with diffuse large B-cell lymphoma, follicular lymphoma and mantle cell lymphoma. Our data emphasize the role of plerixafor in poor mobilizers, but further strategies to improve the apheresis yield especially in patients with NHL are required.

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.

Clinical tumor cell distribution pattern is a prognostically relevant parameter in patients with B-cell chronic lymphocytic leukemia.

BACKGROUND AND OBJECTIVES: B-cell chronic lymphocytic leukemia (B-CLL) cells are variably distributed among the major lymphoid compartments contributing to the heterogeneous clinical presentation and course of this disease. In order to evaluate this variable distribution we propose a model for its clinical assessment. DESIGN AND METHODS: We introduce the model for tumor distribution (TD) assessment based on TTM scoring system, where TD value represents percentage of total tumor mass infiltrating peripheral blood and bone marrow (TD=TM(1)/TTM). TD in B-CLL can be categorized into 3 subgroups: pure leukemia if TD=100%, predominantly leukemia if TD=50-99% and predominantly lymphoma TD<50%. RESULTS: Among 341 B-CLL patients there were 22.6%, 55.1%, 22.3%, pure leukemia, predominantly leukemia and predominantly lymphoma cases, respectively. TD parameter was strongly associated in univariate analysis with TTM size, Rai and Binet stages, spleen size and beta(2) microglobulin. TD was associated with response to therapy and survival, with higher TD values translated into higher response rates and longer survival. However, in univariate and multivariate Cox analysis TD displayed much stronger relationship with prognosis in female patients, where it is the strongest independent predictor of survival along with age and Binet stage. INTERPRETATION AND CONCLUSIONS: TD, a quantitative and simple clinical parameter, easily assessed in all patients, offers a reliable tool for evaluation of tumor cell distribution in B-CLL. It has independent and strong prognostic power in females, as opposed to males, possibly unmasking important, yet unrecognized, biological difference in B-CLL patients.

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.