A new lectin in red kidney beans called PvFRIL stimulates proliferation of NIH 3T3 cells expressing the Flt3 receptor.

A new legume lectin has been identified by its ability to specifically stimulate proliferation of NIH 3T3 fibroblasts expressing the Flt3 tyrosine kinase receptor. The lectin was isolated from conditioned medium harvested from human peripheral blood mononuclear cells activated to secrete cytokines by a crude red kidney bean extract containing phytohemagglutinin (PHA). Untransfected 3T3 cells and 3T3 cells transfected with the related Fms tyrosine kinase receptor do not respond to this lectin, which we called PvFRIL (Phaseolus vulgaris Flt3 receptor-interacting lectin). When tested on cord blood mononuclear cells enriched for Flt3-expressing progenitors, purified PvFRIL fractions maintained a small population of cells that continued to express CD34 after 2 weeks in suspension cultures containing IL3. These cultures did not show the effects of IL3's strong induction of proliferation and differentiation (high cell number and exhausted medium); instead, low cell number at the end of the culture period resulted in persistence of cells in the context of cell death. These observations led to the hypothesis that PvFRIL acts in a dominant manner to preserve progenitor viability and prevent proliferation and differentiation.

Fluoride determination in plasma by ion selective electrodes: a simplified method for the clinical laboratory.

A potentiometric method for the determination of fluoride (F-) in serum and plasma is proposed; it is based on a combination of the single-known-addition method and the electrode slope-by-dilution method. This procedure provides reliable results in extremely low measuring ranges down to 2.5 mug/l, where the electrode slope deviates markedly from Nernstian behaviour. In this method no electrode calibration is required and only one standard is necessary. 1 ml of plasma is sufficient for one analysis. Apart from a 5% enrichment of all samples with a concentrated total ionic strength adjustment buffer, no further preparation of the sample is required. The simplicity of the various pipetting and analytical steps, and also of the evaluation of the readings, may render this method highly suitable for the clinical laboratory. Investigations into the accuracy and precision of the method produced satisfactory results. The recovery in plasma amounted to 99.7%, even in the low measuring ranges. The discrimination capacity of the method amounts to 0.1 mug/l. With the apparatus and experimental procedures described, 18 plasma analyses per day can be performed even at low F- concentrations with which longer electrode stabilization periods are required. Storage of the plasma samples frozen at --20 degrees C for up to 8 weeks exerts no effect on the F- concentration. Problems of sample contamination and other disturbances are discussed. Determinations of normal values in 20 test subjects resulted in a mean value of 10.4 plus or minus 4.01 mug/l (Mean plus or minus S.D.). The modal value amounted to 9.5 mug/l, and the range was between 5.9 and 18.8 mug/l. The F- content of the drinking water supplied to this group of persons amounted to 180 mug/l. The importance of the method has been illustrated using a clinico-nephrological study as an example.

Vertebral compression fractures at the onset of acute lymphoblastic leukemia in a child.

A child with acute lymphoblastic leukemia, spinal osteoporosis with vertebral compression fractures, and hypercalcemia appearing early in the course of the hematologic disease was followed for two and a half years. Bone mineral density (BMD), measured by single photon absorptiometry at the radial shaft, was within normal limits for age and sex. However, x-rays of vertebrae and vertebral BMD, measured by dual photon absorptiometry, showed marked demineralization. Despite leukemic remission, the spinal osteoporosis became worse and the patient required aggressive treatment for eight months. Treatment included 50 units of calcitonin subcutaneously every other day, 1,000 mg/day of oral calcium, and 3,000 IU/day of vitamin D. The back pain disappeared quickly, and laboratory controls showed a significant diminution of bone turnover. No new compression fractures occurred. Eighteen months later, the patient continued in remission and menarche had occurred. Dual photon absorptiometry revealed a significant "catch up" of the lumbar spine BMD. X-ray examination showed a marked remodeling of the vertebral bodies. BMD measurements in this child indicate that bone loss affected the trabecular bone compartment or occurred only at active bone marrow sites. The rapid clinical amelioration and objective biochemical, densitometric, and radiologic evidence of bone improvement warrant further clinical trials on similarly affected patients.

[Monocytoid B-lymphocytic leukemia]. / Leucemia de linfocitos monocitoides B.

The recently described monocytoid B-cell lymphoma is a low-grade lymphoma presenting most frequently in elderly women and commonly associated with autoimmune diseases. Leukaemic expression of this disease has been reported in advanced stages. A case of monocytoid lymphocytosis without lymph node enlargement is presented herein. A 60-year old woman complaining of easy bruises was found to have a 2-cm splenomegaly. Her laboratory data included the following: haemoglobin, 125 g/L; haematocrit, 0.35 L/L; white cell count, 29 x 10(9)/L with 32% PMN, 3% stabs, 2% myelocytes, 1% metamyelocytes, 30% lymphocytes and 32% atypical mononucleated cells showing wide, pale cytoplasm neatly contoured and oval nucleus with monocytoid features. The basal coagulation study showed prothrombin 50%, APTT 40 seconds, fibrinogen 68 mg/dL and FDP between 80 and 160 ng/dL. Splenomegaly without lymph-node enlargement was found on CT scan. The bone-marrow biopsy showed a 68% monocytoid lymphocytic infiltration, acid-phosphatase positive and tartrate-sensitive, without fibrosis. Bone-marrow and peripheral immunophenotype showed those cells to be CD22, CD 19 and CD11 positive, while T and CD25 markers were absent. The patient was treated with alpha-2b interferon at a dose of 3MU three times a week for 6 months, with general improvement and regression of the leukaemic expression. Eleven months after diagnosis she died of a central nervous system haemorrhage. The morphological, immunological and cytochemical features of the monocytoid lymphocytes in this case are commented, along with their variable behaviour. A review of the literature is also carried out, attention being laid on the onset and the response to therapy of B-cell monocytoid lymphomas as the singularity of this case lies on its exclusively leukaemic onset. It is concluded that an interrelationship between monocytoid B-lymphocytic leukaemia and B-cell monocytoid lymphoma might possibly exist, such as that between chronic lymphocytic leukaemia and diffuse lymphocytic lymphoma.

[Safe minor surgery in patients taking anticoagulants]. / Cirugía menor segura en pacientes anticoagulados.

The effectiveness of a commercial drug containing fibrinogen, thrombin and factor XIL (Tissucol, Immuno) was assessed in 127 patients receiving oral anticoagulant treatment with acenocoumarin who were subjected to 183 minor surgical procedures: 107 exodontia, 53 periodontal procedures, 17 combinations of the former, 4 liver biopsies and 2 skin biopsies. All but the liver biopsies were performed in the outpatient clinic. Mild haemorrhage appeared in 21 instances. None of the patients required systemic administration of coagulation factors, and the maneuvers did not take any longer than in patients with integrity of the coagulation mechanisms. The outstanding benefits of this technique are: less discomfort for patients, who can be subjected to a single procedure while otherwise requiring several sessions; anticoagulation needs not be discontinued, subcutaneous heparin being otherwise necessary; low risk of complications and avoidance of substitutive therapy; lesser economic burden, as no hospital admission is needed.