C-kit receptor (CD117) expression on plasma cells in monoclonal gammopathies

The surface expression of CD117 antigen (c-kit) on plasma cells from 158 multiple myeloma (MM), 12 plasma cell leukemia (PCL), 7 MGUS, 7 IgM lymphoplasmacytic lymphoma patients and 10 healthy subjects has been analyzed by flow cytometry using triple staining with the monoclonal antibodies CD138, CD117 and CD38. The antigen expression intensity was calculated as relative fluorescence intensity (RFI) and for direct quantitative analysis the QuantiBRITE test (Becton Dickinson) was applied. Antibody bounding capacity (ABC) was calculated using QuantiCALC software. CD117 antigen was present in 49/158 MM, 5/12 PCL and 5/7 MGUS patients. The RFI values ranged from 0.2 to 20.2 in particular MM patients (mean: 11.0 ± 5.3; median 11.5) while the number of CD117 binding sites (ABC) on MM plasma cells ranged from 637 to 6217 (mean: 3029 ± 1568; median 2946) (r = 0.8328). In responsive to chemotherapy c-kit positive MM patients the percentage of CD117⁺ plasma cells in the bone marrow decreased significantly while in c-kit negative MM patients the percentage of CD117⁺ cells in bone marrow did not change and remained in the normal limits. When comparing the clinical and biological disease characteristics (monoclonal protein isotype, albumin, β₂-microglobulin, lactate dehydrogenase, stage of disease, response to chemotherapy, survival time) of c-kit positive and c-kit negative cases, no significant differences were found. In CD117 positive PCL cases expression of CD117 was detected in bone marrow plasma cells as well as in peripheral blood plasma cells. Normal plasma cells and those in IgM lymphoplasmacytic lymphoma did not show reactivity for the CD117 antigen. We conclude that it may be rationale to consider usefulness of therapy with tyrosine kinase inhibitors in the management of c-kit positive plasma cell proliferations. In one third of MM and PCL patients c-kit antigen could be considered as a "tumor associated marker" and together with CD38 and CD138 it may be of value for the identification of the malignant clone in minimal residual disease as it was first suggested by Spanish authors.     

Procalcitonin as a marker of perinatal infection in newborn--preliminary data

Intrauterine and intrapartum infections in newborn infants are still difficult to recognise. The newborn does not manifest the classic clinical signs of infection usually observed in children and adults and up to now there is no good laboratory marker. In the last few years, procalcitonin (PCT) has been found to increase during different inflammatory processes, especially bacterial ones. In this study we analysed the clinical value of PTC in parturient, umbilical cord and newborn blood for predicting perinatal infection. MATERIAL AND METHODS: Thirty parturients with symptoms of intrauterine infection were classified for this study. Blood samples were obtained from the mother, the umbilical cord and the newborn on the second day of life. Serum was stored at -70 degrees C and thawed at the time of analysis. Among the newborns there were 21 infants without and 9 with symptoms and signs of infection. PCT concentration was measured by immunoluminometric assay--LUMI test PCT (BRAHMS). RESULTS: Statistically significant results were found on the second day of life: 5.83 (4.70) ng/ml in ill, 1.41 (0.68) ng/ml in healthy (p < 0.0005). We observed a significant correlation between PCT concentration in mother and umbilical cord blood (y = 0.40x + 1.06; p < 0.05), as well as between umbilical cord blood and venous blood on the second day of life in newborns (y = 0.16x 1.21; p < 0.01). CONCLUSIONS: Measurement of PCT concentration in perinatal period in the mother and in umbilical cord blood of the newborn may be useful for early diagnosis and monitoring of infectious complications in neonates. We need more data on reference ranges of PCT concentration in pregnant women, parturients and umbilical cord blood.     

Determination of von Willebrand factor activity with collagen-binding assay and diagnosis of von Willebrand disease: effect of collagen source and coating conditions

The collagen-binding assay was recently recommended as the new method for determining von Willebrand factor activity.(1-3) The assay is based on measurement of the quantity of von Willebrand factor molecules bound to collagen, similar to the procedure for an enzyme-linked immunosorbent assay. Many authors have reported problems in efficiently coating microplates with collagen and have suggested special procedures requiring chemical modification of the microplate surface and collagen or a high concentration of this protein and long incubation times.(4,5) Other studies indicate that the reasons for this problem are the origin of the collagen used for coating and the conditions under which the coating procedure is carried out. Modification of coating conditions and the use of an alkaline buffer permits the use of relatively low concentration of collagen, 5 to 10 microg/mL, and allows the test to be completed in one day. This procedure is useful in the diagnosis of von Willebrand disease and allows researchers to distinguish between disease types I and II.     

N-methyl-2-pyridone-5-carboxamide: a novel uremic toxin?

BACKGROUND: N-methyl-2-pyridone-5-carboxamide (2PY) is one of the end products of nicotinamide-adenine dinucleotide (NAD) degradation. We recently found that serum 2PY concentrations in chronic renal failure (CRF) patients were enhanced to the values, which are potentially toxic. The aim of this study was to determine whether 2PY is an inhibitor of poly(ADP-ribose) polymerase, the nuclear enzyme that is highly involved in variety of physiologic events, including regulation of DNA replication and DNA repair. METHODS: High-performance liquid chromatography (HPLC) was used to determine 2PY and other NAD catabolite concentrations in serum of: nondialyzed patients; patients chronically hemodialyzed; patients after kidney transplantation; and healthy individuals (control group). Moreover, the effect of nicotinamide and 2PY on poly(ADP-ribose) polymerase (PARP-1) in vitro was studied. RESULTS: The serum nicotinamide, 2PY, and 4PY (N-methyl-4-pyridone-3-carboxamide) concentrations are many times elevated in nondialyzed CRF patients when compared with controls. The direct correlations were found between serum 2PY (as well as 4PY and nicotinamide) concentrations and serum creatinine concentration, and negative correlations between serum concentrations of these compounds and creatinine clearance. The concentration of 2PY decreases considerably after hemodialysis (HD) session, but elevates back 48 hours later. It permanently declines after kidney transplantation. Nicotinamide and 2PY significantly inhibit PARP-1 activity in vitro. CONCLUSIONS: Increased serum 2PY concentration, along with a deterioration of kidney function and its toxic properties (significant inhibition of PARP-1 by 2PY), suggest that it could be a novel uremic toxin.     

Selective opening of the blood-tumor barrier by a nitric oxide donor and long-term survival in rats with C6 gliomas

OBJECT: The response of brain tumors to systemic chemotherapy is limited by the blood-tumor barrier (BTB). Nitric oxide (NO) has been implicated in the regulation of vascular permeability and blood flow. The authors evaluated the effects of exogenous NO, which was released from a short-acting NO donor (Proli/NO), and those of NO metabolites on the capillary permeability of tumors and normal brain tissue by using quantitative autoradiography in a C6 glioma model in rats. METHODS: The Proli/NO was infused at a wide dose range (10(-2) to 10(-12) M) either intravenously or into the internal carotid artery (ICA) and demonstrated substantial tumor-selective increases in blood-brain barrier (BBB) permeability in response to various-sized tracers ([14C]aminoisobutyric acid, [14C]sucrose, [14C]dextran). Internal carotid artery or intravenous administration of sodium nitrite had a comparable effect on BTB permeability. The NO effect on microvascular permeability could be obtained without causing hemodynamic side effects. The effect of NO on the efficacy of carboplatin chemotherapy was investigated in intracerebral C6 gliomas. Simultaneous intravenous infusions of Proli/NO (10(-6) M) and carboplatin (20 mg/kg) led to long-term survival in 40% of rats harboring intracerebral C6 gliomas compared with control animals receiving ICA or intravenous infusions of carboplatin, Proli/NO, or vehicle alone. No residual tumor was demonstrated on histological or magnetic resonance imaging studies performed in rats treated with Proli/NO and carboplatin, and no toxicity was observed. CONCLUSIONS: This new approach demonstrated the in vivo efficacy and safety of NO and nitrite in enhancing the delivery of systemically delivered radiolabeled tracers and carboplatin into rat gliomas. The NO-induced tumor-selective BBB disruption and intravenous carboplatin chemotherapy may be more efficacious than current chemotherapy strategies against brain tumors.     

Comparison of anterior and posterior surgical approaches in the treatment of ventral spinal hemangioblastomas in patients with von Hippel-Lindau disease

OBJECT: Von Hippel-Lindau (VHL) disease is an autosomal-dominant neoplastic syndrome with manifestations in multiple organs, which is evoked by the deletion or mutation of a tumor suppressor gene on chromosome 3p25. Spinal hemangioblastomas (40% of VHL disease-associated lesions of the central nervous system) arise predominantly in the posterior aspect of the spinal cord and are often associated with an intraspinal cyst. Rarely, the tumor develops in the anterior aspect of the spinal cord. Ventral spinal hemangioblastomas are a surgical challenge because of difficult access and because vessels feeding the tumor originate from the anterior spinal artery. The goal of this study was to clarify whether an anterior or posterior surgical approach is better for management of hemangioblastomas of the ventral spinal cord. METHOD:. The authors performed a retrospective analysis of clinical outcomes and findings on magnetic resonance (MR) imaging studies in eight patients (two women and six men with a mean age of 34 +/- 15 years) who underwent resection of ventral spinal hemangioblastomas (nine tumors: five cervical and four thoracic). Two surgical approaches were used to resect these tumors. A posterior approach was selected to treat five patients (laminectomy and posterior myelotomy in four patients and the posterolateral approach in one patient); an anterior approach (corpectomy and arthrodesis) was selected to treat the remaining three patients. Immediately after surgery, the ability to ambulate remained unchanged in patients in whom an anterior approach had been performed, but deteriorated significantly in patients in whom a posterior approach had been used, because of motor weakness (four of five patients) and/or proprioceptive sensory loss (three of five patients). This difference in ambulation, despite significant improvements over time among patients in the posterior access group, remained significant 6 months after surgery. In all cases, MR images revealed complete resection of the tumor and in five patients significant or complete resolution of the intramedullary cyst was demonstrated (present in six of eight patients). CONCLUSIONS: The outcomes of these eight patients with hemangioblastomas of the ventral spinal cord indicate that both immediate and long-term results are better when an anterior approach is selected for resection.