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R L Verwilghen

Publications and source records attributed to R L Verwilghen.

At least 19 recordsLinked to original sources
PubMed1991

K2- or K3-EDTA: the anticoagulant of choice in routine haematology?

The choice of K2- or K3-EDTA as the preferred anticoagulant for blood count remains controversial. We compared the effect of different concentrations of both anticoagulants on normal blood. In optimal conditions (appropriate anticoagulant concentration and measurements done between 1 and 4 h after phlebotomy), no marked differences are seen between either EDTA salt. Important discrepancies appear, however, in less optimal conditions, as often happens in day to day practice. The packed cell volume, when measured on centrifuged blood, decreases with increasing anticoagulant concentrations and this is most pronounced with the K3 salt. This phenomenon has been reported by different authors and is ascribed to shrinking of erythrocytes in an hypertonic medium. Automated instruments react in a different way, their MCV is not influenced by K3-EDTA concentrations up to ten times normal, while K2-EDTA, at high concentrations, results in a slight increase in MCV, as measured with three of the instruments. With most instruments, the accuracy of the white cell count is not markedly influenced. However, when measured with the Unipath CD 3000 all tested blood samples, taken in high K3 (but not in K2) concentrations, showed an appreciable decrease in the leucocyte count (to less than 50% of the original value, at a concentration of 15 g/l, 24 h after blood collection). Measurement of RDW and automated differentials is also influenced by the choice of anticoagulant when determinations are done in less than optimal conditions. We conclude that the choice of anticoagulant, its use at an appropriate concentration and the age of the blood sample are important matters and should be given due consideration.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗
PubMed1991

Monocyte counting: discrepancies in results obtained with different automated instruments.

To determine the accuracy of several methods for measuring the monocyte count, the results obtained by a number of different automated cell counters were analysed. Considerable discrepancies occurred for monocyte counts obtained in normal blood among the counters. The results of a visual monocyte count on a total of 800 leucocytes were used as the reference method. The technique of measuring the monocyte count by using dual staining with monoclonal antibodies CD45 and CD14 provided the closest agreement with the reference method. Six other automated counting systems were assessed. Two of these systems (Coulter VCS and Technicon H1) gave results, which, although under-estimating monocytosis, correlated well with the results obtained by the reference technique. A third system (Toa Sysmex NE-8000) gave unreliable results. Three of the automated systems evaluated measured a "third population"--that is, monocytes together with other leucocytes. One of these systems (Ortho ELT 1500), overestimated the count, as expected, but correlated well with the reference method. The second of these "third population counters" (Coulter S Plus IV) correlated moderately well with the reference monocytosis, while the Toa Sysmex E-5000 correlated poorly. It is clear that problems exist in the evaluation of different instruments for counting monocytes. An accurate and reliable reference method is a pre-requisite to evaluate this aspect of cell counters. As the visual method is too cumbersome a different reference method would be useful. Based on the results of this study, it is suggested that the technique using fluorescence labelled monoclonal antibodies should be regarded as an acceptable alternative.

Adult↗
PubMed1990

Reticulocyte count using thiazole orange. A flow cytometry method.

Recently flow cytometry techniques have been developed to replace the microscope reticulocyte count. We used thiazole orange, a RNA binding fluorochrome, to discriminate reticulocytes from mature erythrocytes. Thiazole orange and the Retic-COUNT software package were evaluated for performance of routine analysis on different flow instruments. The applied methodology analysed 10(4) cells semi-automatically in an easily performed manner. Consistent results were obtained with dipotassium EDTA anticoagulated blood (stable for 30 h after venesection), with incubation times in thiazole orange solution ranging from 2 to 7 h at 25 degrees C. This allowed flexibility in specimen collection and storage and assay performance with no change in results. Changes of incubation temperature up to 30 degrees C had no measurable effect. The values obtained showed good linearity, precision and accuracy for normal, low and high reticulocyte counts. However interferences were observed: RBC autofluorescence, nucleated RBC, Howell-Jolly bodies, high leucocyte count, high platelet count and giant platelets, all falsely increased the number of reticulocytes. These artifacts were eliminated by software gate corrections, thus leaving less than 5% of the specimen to be reanalysed by the microscopic method. The thiazole orange flow cytometric method was determined to be a fast, reliable method for the routine clinical quantitation of reticulocytes.

Benzothiazoles↗
PubMed1988

Congenital macrothrombocytopenia, leucocyte inclusions, deafness and proteinuria: functional and electron microscopic observations on platelets and megakaryocytes.

We report a patient with a variant of Alport's syndrome: macrothrombocytopenia, leucocyte inclusions, deafness and proteinuria. Ultrastructural studies revealed giant spheroid platelets with a high density of organelles and a disorganized microtubular system. In addition, Fechtner inclusions were observed in neutrophils of the patient and her mother. In platelet rich plasma platelets aggregated normally for the low platelet number, although no shape change was visible. Platelet studies in whole blood using impedance aggregometry gave supernormal aggregation curves; this is not in agreement with the abnormally long bleeding time, showing the limited usefulness of this technique in patients with such large platelets. The megakaryocytes (MK) showed two different distribution patterns of the demarcation membrane system (DMS), which may explain the production of few large platelets. The formation of platelets occurred by fragmentation of the granular zone of the MKs, which seemed to be followed by expulsion of platelets through openings of the peripheral zone. The involvement of cytoskeletal structures in the organization of the DMS and the expulsion of platelets is discussed.

Adult↗
PubMed1987

The myelodysplastic syndromes.

The myelodysplastic syndromes constitute a fascinating model for monoclonal premalignant disorders. Haemopoiesis is 'dysplastic' with inefficient maturation of a slowly expanding or sometimes of a stable population, of blood cell precursors. About one third of the patients evolve into acute leukaemia, the result of either a progressive expansion of the original clone or a new mutation producing a more malignant subclone. The majority of patients suffer from the results of bone-marrow insufficiency, with pancytopenia and possibly immune deficiency. Characteristic karyotype anomalies involving mainly chromosomes 5, 7 and 8 are seen in half the patients. These same chromosomes are known to carry different oncogenes. The myelodysplastic syndrome occurs mainly in the aged and there is a moderate male preponderance. The incidence is still unknown but is probably similar to that of acute leukaemia. The etiology is also unknown; however, a secondary myelodysplastic syndrome precedes acute myeloid leukaemia, as a late consequence of chemo- and radio-therapy in treated Hodgkin's disease. This suggests that environmental mutagens might also be involved in primary myelodysplastic syndromes. Treatment remains highly unsatisfactory but a few recent developments improve prognosis, at least in the younger patient.

Humans↗
PubMed1987

The spleen and haemolysis: evaluation of the intrasplenic transit time.

The mean intrasplenic red cell transit time (STT) and the slow mixing splenic red cell volume (SSV) have been measured in patients with hereditary spherocytosis (HS), autoimmune haemolytic anaemia (AIHA) and lymphoproliferative disease (LD). There was an inverse relationship between the mean red cell life span (MRCLS) and the STT in HS (r = -0.96, P less than 0.001) and in AIHA (r = -0.90, P less than 0.001). No such relationship existed in LD. The size of the spleen and the SSV were not related to the severity of haemolysis. Our data offer strong evidence for the conditioning effect of the spleen on HS- and AIHA red cells and suggest that the STT is an index of the adverse effect of the spleen on red cells in patients with HS or AIHA.

Anemia, Hemolytic, Autoimmune↗
PubMed1987

The role of intensive remission induction and consolidation therapy in patients with acute myeloid leukaemia.

Sixty-one patients with AML, 59 adults and two children, were treated with intensive remission induction and consolidation therapy. The median age was 36 years. Forty-four (72%) patients entered complete remission (CR); 11 patients received a bone marrow transplantation. The median survival of complete remitters was 26.5 months; the probability of remaining in CR at respectively 1 and 2 years was 75% and 62%. The only factor significantly correlated with the outcome of remission induction, survival and duration of CR was age. Patients less than 30 years fared significantly better than those 30 years or older; no difference in outcome was observed between patients aged 30-50 and those over 50 years. In patients less than 30 years the CR rate was 95%; 75% of them were still alive at 2 years and only one (5%) has relapsed. In contrast, in patients 30 years or older the CR rate was 60% and the median survival only 11.5 months, 50% of the complete remitters in this age group have relapsed. Morbidity from intensive consolidation therapy was considerable; more than 50% of consolidation courses were complicated by high fever, needing urgent admission; only four (3%) courses had a fatal event. It is concluded that intensive consolidation therapy may be considered as a major advance in the treatment of younger patients with AML, while its role in older individuals remains questionable. A possible explanation for the completely different outcome in younger and older patients with AML is discussed.

Adolescent↗
PubMed1987

Effect of acute lead intoxication on the ultrastructure of rat erythroblasts and reticulocytes. Morphometric analysis and röntgen micro-analysis.

Effect of 17 hr intoxication of lead on the different maturation stages of erythroid cells were studied in rat. Morphometric methods were used to analyse the lead-induced ultrastructural changes in the early, intermediate, late erythroblasts and reticulocytes. It was found that the toxic effect of lead increases with maturation. Energy-dispersive Röntgen micro-analysis showed that fibrillar structures within vesicles and endoplasmic reticulum contained lead.

Acute Disease↗
PubMed1986

Oral bromovinyldeoxyuridine therapy for herpes simplex and varicella-zoster virus infections in severely immunosuppressed patients: a preliminary clinical trial.

Twenty-five patients with haematological diseases were treated orally with the highly potent and selective anti-herpes agent, bromovinyldeoxyuridine (BVDU), in a dosage of 7.5 mg/kg/day (divided over three or four doses a day) for 5 days for an intercurrent mucocutaneous herpesvirus infection. Of these 25 patients, 8 were severely granulocytopenic at the time of the viral infection, and 12 recently had undergone bone-marrow transplantation; 5 were under cytotoxic therapy for a lymphoproliferative disorder; 13 had herpes simplex virus type 1 (HSV-1); 1 had herpes simplex virus type 2 (HSV-2); and 11 had varicella-zoster virus (VZV) infection. In all but two patients, BVDU arrested progression of the HSV or VZV infection within 1-2 days after treatment was started. One of the two patients who failed to respond to BVDU had an HSV-2 infection. The other had an HSV-1 infection, which was highly sensitive to BVDU in vitro; BVDU may have failed in this patient because of incomplete drug intake or profuse diarrhoea, or both. The results of this preliminary uncontrolled clinical trial suggest that BVDU may be an effective and safe drug for the oral treatment of HSV-1 and VZV infections in severely immunosuppressed patients.

Adolescent↗
PubMed1986

Effects of quinolones on granulocyte function in vitro.

Granulocytes (PMN) play an important role in antibacterial host defence. The modulation of PMN-function by different antibiotics has been shown previously. Therefore, we investigated the possible immuno-modulatory effects of four new quinolone antibiotics: ciprofloxacin, norfloxacin, pefloxacin, ofloxacin. Pure PMN-preparations were obtained from healthy volunteers and incubated for 30 min at 37 degrees C with the different quinolones at different concentrations (0.1-1-5-10 mg/l). A complete PMN-functional profile was assayed. At all concentrations tested no significant differences were seen for myeloperoxidase content, superoxide production and chemiluminescence. A significant stimulation of phagocytosis and killing occurred at 10 mg/l of norfloxacin and at 10 mg/l of pefloxacin. An increase of chemotaxis towards formyl-methionyl-leucyl-phenylalanine was noted at 10 mg/l of ofloxacin, while stimulation of hexose monophosphate shunt was seen at 1 mg/l of ciprofloxacin and 10 mg/l of ofloxacin. The mechanism whereby both subinhibitory and inhibitory concentrations of quinolones moderately influence PMN-responsiveness is not yet known. Further studies are needed to elucidate the nature of this quinolone-effect and to assess its relevance in vivo.

Anti-Infective Agents↗
PubMed1986

The histological characterization of ALIP in the myelodysplastic syndromes.

Bone marrow biopsies of patients with a myelodysplastic syndrome (MDS) may, in the absence of an increased number of blasts in the bone marrow smears, contain small clusters of immature precursors. The presence of these cell nests, previously described as "abnormal localized immature precursors" or ALIP, bears a strong prognostic value predisposing patients to early death with an increased risk to develop myeloid leukaemia. In order to describe and delineate this histological characteristic more precisely, we compared bone biopsies of patients with MDS, used in these previous studies, with bone marrow biopsies performed for staging procedures in patients with Hodgkin's disease, non-Hodgkin's lymphoma and carcinoma. From this comparison we conclude that immature precursors are readily differentiated from proerythroblasts, myeloblasts and small-sized megakaryocytes, and that they most probably represent precursors of the myelo-monocytic-erythroid series. A clearcut increase in their number, mostly resulting in the formation of small clusters, is only found in biopsies from patients with MDS.

Bone Marrow↗
PubMed1986

Quantitative assessment of erythropoiesis in bone marrow expansion areas using 52Fe.

Quantitative 52Fe scans were performed in 180 patients. Expansion of bone marrow was observed in 70. This bone marrow expansion was a nearly constant feature in haemolytic anaemia and in sideroblastic anaemia. It occurred in a third of the patients with myelofibrosis. In patients with polycythaemia rubra vera, expansion was noticed in only two out of seven. Erythropoiesis in expansion areas occurred despite persistence of fat in the iliac crest bone marrow biopsy. It could exist with a slight increase in erythropoiesis and might develop only after a long period of erythropoietic stimulation. Increased marrow activity can take place without erythropoietic expansion in long bones. The fraction of iron uptake in expansion areas did not exceed a third of total marrow iron uptake. With increasing erythropoiesis, the increase in iron uptake in expansion areas was less marked than the increase in the central areas. Erythropoiesis in expansion areas was usually not of major quantitative importance but could nevertheless reach the erythropoiesis of a normal adult.

Adult↗