Biomedical subjects

N Clausen

Publications and source records attributed to N Clausen.

At least 37 records · Page 2Linked to original sources

PubMed1996

Relation of blast cell survival and proliferation to chemotherapy resistance in AML.

We have investigated the in vitro blast cell survival (viability) and drug resistance to cytosine arabinoside (Ara-C), daunorubicin (Dau), mitoxantrone (Mitox) and aclarubicin (Acla) of fresh leukaemic blast cells from 80 patients with newly diagnosed acute myeloid leukaemia (AML) employing the semiautomated colourimetric MTT(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide)-assay. In 15 cases we concurrently investigated the relation between in vitro blast cell survival (MTT assay) and blast cell proliferation (3H-thymidine incorporation) in the presence and absence of myeloid growth factors (GFs) G-CSF, GM-CSF and IL-3 (individually and in combination). A highly significant correlation was found between blast cell survival and blast cell proliferation (r = 0.87, P < 1 x 10(-4). Furthermore, in 40 evaluable adult patients who completed intravenous induction chemotherapy and were evaluable for response to chemotherapy we found a positive correlation between in vitro blast survival (MTT assay) and response to chemotherapy with high blast survival being associated with poor response to chemotherapy (P = 0.05). Moreover, in a multivariate analysis, high blast cell survival was significantly associated with high CD13 expression and monocytic phenotype (P = 0.0003 and P = 0.02, respectively). Furthermore, we found an inverse relationship between the baseline proliferation of the blasts and the magnitude of response to the GFs (P < 0.02), indicating that cells with low baseline proliferation were more readily stimulated by growth factors. Finally, we found a significant correlation between leukaemic cell survival and cellular drug resistance towards Dau (P = 0.001) and Mitox (P = 0.03), but not towards Ara-C (P = 0.68) and Acla (P = 0.13). We conclude that high in vitro leukaemic cell survival is associated with drug resistance in vivo and in vitro, and furthermore is correlated with high blast cell proliferation and some adverse prognostic factors previously identified in AML.

Aclarubicin↗

PubMed1996

Parvovirus B19 infection and Diamond-Blackfan anaemia.

It is the purpose of the study to report the frequency of parvovirus in children with a diagnosis of Diamond-Blackfan anaemia and to discuss the possible aetiological role of parvovirus in Diamond-Blackfan anaemia. We found parvovirus DNA in 3 of 11 bone marrow smears. Giant pronormoblasts showed low sensitivity (33%) and poor specificity (75%). The presence of giant pronormoblasts was associated with a very high myeloid:erythroid ratio, and may not be specific for parvovirus infection, but a feature of severely suppressed erythropoiesis. The three parvovirus-positive patients were the only children who experienced a remission, and who are free of medication. The seven surviving parvovirus-negative patients are all currently on steroid treatment.

Bone Marrow↗

PubMed1996

Severe aplastic anaemia in the Nordic countries: a population based study of incidence, presentation, course, and outcome.

PURPOSE: Incidence data for severe aplastic anaemia (SAA) in children are scanty and vary. Few population based studies have been reported. A retrospective and prospective study was conducted to determine the incidence and course of SAA. PATIENTS AND METHODS: All children with a diagnosis of SAA in the Nordic countries from 1982 through 1993 were registered and have been followed up since 1987. RESULTS: A total of 101 children were diagnosed with SAA. The mean annual child population was 4.31 million. A constant incidence of 1.95/million children/year was found: 2.4 for boys and 1.5 for girls. A non-significant increase of cases occurred from November to March. Possible aetiological agents were noted in 29%. The actuarial survival was 79% after one year and 68% after five years without significant difference between boys and girls. CONCLUSION: The incidence of SAA in the Nordic countries remains stable with a preponderance among boys. SAA has still a high initial mortality and a risk of late deaths.

Adolescent↗

PubMed1996

Intensive chemotherapy in childhood myelodysplastic syndrome. A comparison with results in acute myeloid leukemia.

Myelodysplastic syndrome (MDS) in children is often considered as a variant of acute myeloid leukemia (AML) and frequently treated as such. However, there are very few reported data on the outcome following AML treatment. We analyzed 20 consecutive cases of de novo MDS treated in Denmark according to the NOPHO AML protocols. The results were compared with those obtained in 31 children with de novo AML treated with the same protocols, and with the outcome in 10 children with MDS who received allogeneic bone marrow transplantation (BMT) without prior AML therapy. Distinction between MDS and AML was made morphologically according to the FAB criteria. All children were followed for at least 37 months. The proportion of complete remission in MDS and AML was 35 percent vs 74 percent. (P = 0.005), resistant disease 25 percent vs 10 percent (P = 0.14), death in cytopenia 40 percent vs 16 percent (P= 0.06), and 3-year survival 15 percent vs 35 percent. (P = 0.11), respectively. Duration of treatment-related cytopenia was similar in MDS and AML, except for a longer period of leukopenia in MDS following the second course of induction. Seven of 10 MDS children receiving BMT without prior chemotherapy are long-term survivors. Our data suggest that conventional AML regimens are associated with a low rate of complete remission, a high risk of death in cytopenia, and a limited curative potential in childhood MDS. Allogeneic BMT was in contrast associated with a high survival rate. BMT may, at least in some patients, be performed successfully without prior induction chemotherapy. The different response to therapy in MDS and AML may reflect fundamental biological differences between the two conditions.

Acute Disease↗

PubMed1995

Partial triplication (7q) in a child with acute lymphoblastic leukemia demonstrated with conventional cytogenetics, PRINS, and chromosome painting.

In this report we describe a partial triplication (7q) and other structural aberrations found in a child with acute lymphoblastic leukemia (ALL), and we demonstrate the importance of PRimed IN Situ labeling (PRINS) and chromosome painting as a support to banding analysis for the clarification of complex structural chromosome rearrangements. Initially, the der(7) was interpreted as der(7)t(1;7;7). However, PRINS and chromosomes painting showed that der(7) consisted entirely of chromosome 7 material. Further, a derivative chromosome interpreted by banding analysis as a der(17)t(?1;17) was shown to be der(17)t(13;17) by the newly developed PRINS painting technique.

Child↗

PubMed1995

Differential expression levels of the heat shock protein 27 isoforms in pediatric normal, nonleukemic and common acute lymphoblastic leukemia B-cell precursors.

Heat shock protein 27 (hsp27) may function as a regulator of microfilament dynamics and may participate in signal transduction pathways of different cell growth regulators, with the mitogen-activated protein kinase-activated protein (MAPKAP) kinase 2 being a major enzyme responsible for its phosphorylation. Using two-dimensional gel electrophoresis, we have compared the expression levels of two hsp27 isoelectric variants (hsp27 isoforms) M2 (molecular weight, 26 kD; isoelectric point, 6.02) and M3 (molecular weight, 26 kD; isoelectric point, 5.60) in pediatric bone marrow CD19+CD10+B-cell precursors (BCPs) purified from either common acute lymphoblastic leukemia (c-ALL) patients, normal donors, or non-c-ALL patients. Compared with normal BCPs, we found increased hsp27 expressions (M2 isoform) (by a factor 5 to 9 of mean level) in c-ALL as well as in non-c-ALL (nonleukemic) precursors. Though increased phosphorylation of hsp27 (M3 isoform) was observed in BCPs from c-ALL patients at relapse (by a factor 3 of mean level compared with normal BCPs and precursors from c-ALL at diagnosis), which might represent a differential enzymatic activity, this was not distinguishable from that of non-c-ALL patients. Therefore, our studies suggest constitutive differences of hsp27 isoforms between pediatric leukemic BCPs and their relatively low-expressing, immunophenotypically normal bone marrow counterparts. In light of the occasional and possibly transient increase of hsp27 expression during nonleukemic BCP differentiation and the possible role of hsp27 in signal transduction to microfilaments, these differences might be of considerable biologic interest and of importance in future studies of regulated normal or dysregulated leukemic hematopoietic cellular differentiation.

Adolescent↗

PubMed1995

Myelodysplastic syndrome in a child with constitutional trisomy 8 mosaicism and normal phenotype.

Trisomy 8 is a frequently acquired cytogenetic abnormality in myeloid malignancies, but may also represent a constitutional chromosome abnormality with a wide phenotypic variation. We report a case of myelodysplastic syndrome (MDS) that developed in a child with trisomy 8 mosaicism and normal phenotype. Bone marrow (BM) cells all showed trisomy 8 with additional clonal abnormalities in most cells. Based on the present case and a review of previously published cases of myeloid malignancies in patients with trisomy 8 mosaicism, it appears likely that the malignant cells developed from the trisomic cell population, suggesting that constitutional trisomy 8 may be a predisposing condition to myeloid malignancies. Trisomy 8 in malignant cells is usually considered an acquired abnormality, but this implies a risk of ignoring a constitutional trisomy 8 mosaicism. Examination for constitutional trisomy 8, despite a normal phenotype, may therefore be warranted in hematologic malignancies with trisomy 8 of BM cells to evaluate further the possible association and to preclude erroneous use of trisomy 8 as a tumor marker.

Child↗

PubMed1995

Capnocytophaga (Capnocytophaga ochracea group) bacteremia in hematological patients with profound granulocytopenia.

The clinical and microbiological features of 7 cases of bacteremia due to Capnocytophaga (Capnocytophaga ochracea group) are reported. They were diagnosed during 1991-93 at three hospital clinics. Five patients were < 10 years old and all had hematological disorders, 4 acute lymphoblastic leukemia and 1 each had aplastic anemia, non-Hodgkin lymphoma, and myelodysplastic syndrome. All were profoundly granulocytopenic with an absolute granulocyte count < 0.13 x 10(9)/l, and all but 1 had oral lesions as a possible portal of entry. A favourable response to antibiotic therapy was recorded in all patients but one who, being profoundly granulocytopenic, rapidly succumbed to Pseudomonas aeruginosa septicemia. None of the isolates were beta-lactamase producers. In addition to penicillin the isolates were susceptible to broad-spectrum cephalosporins and ciprofloxacin, but resistant to aminoglycosides.

Adolescent↗

PubMed1994

[HIV antibody positive children in Denmark].

The AIDS-committee of The Danish Society of Paediatrics has done a nation-wide study among infants and children under the age of 15 with AIDS or HIV-antibodies in preparation for planning prevention and treatment. Clinical data have been collected from the Departments of Paediatrics and Infectious Diseases, Haemophilia, Dermatology and Internal Medicine up to 1 March 1993. The study includes 44 infants with a risk of vertical transmission from the mother and 16 children with haemophilia. No cases were found to be infected by blood-transfusion. Twenty of the 44 infants with congenital HIV-antibodies were HIV-infected. Seven of them died from AIDS, 10 currently have AIDS and three are asymptomatic. Seventeen infants are well and HIV-antibody negative after the age of 18 months. Seven infants still have unclarified status, but all are well. Three of the patients with haemophilia are dead. The 13 others do not have AIDS. It is surprising that most of the infected infants' mothers were not known to be infected before the infants got sick. Thus infected infants exist in families who are not suspected to be HIV-infected. The AIDS-committee of The Danish Society of Paediatrics has proposed recommendations for HIV-testing of infants and children. HIV-infected families need comprehensive psychosocial care. The risk-factor from blood-transfusion is now eliminated, but vertical transmission will continue to be a risk-factor. The size of the problem in Denmark will not be known until an epidemiological study of pregnant women has been conducted.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Hereditary spherocytosis: diagnostic and anaemia-associated aberrations of ghost proteins.

Various disorders of the red cell skeleton and membrane have been described in hereditary spherocytosis. To elucidate which aberrations could be used for identification of HS patients in a Danish population, we examined ghosts from 17 HS patients and 20 normals by use of SDS-gel scanning, native spectrin extraction, and limited tryptic digestion. Compared to normals, HS patients had significantly lowered alpha-spectrin (p < 0.004), protein 4.2 (p < 0.025), and actin (p < 0.05), and significantly increased anion-transporter (p < 3 x 10(-6)) and glyceraldehyde-3-phosphate dehydrogenase (G3PD, p < 0.04). Sixteen out of 17 HS patients could be identified by aberrations of the anion-transporter or protein 4.2 outside a 95% confidence interval for normals. Extraction of native spectrin and limited tryptic digest showed no difference between normals and HS patients. RBC separated into young and old fractions were used to examine the occurrence of protein aberrations associated with RBC age. Young RBC contained more G3PD (35%) and less protein 4.1 (6.5%) and actin (8.7%) than old. In male HS patients an increased G3PD content showed a linear correlation (p < 0.001) with a low concentration of blood haemoglobin. We conclude that aberrations of G3PD, and possibly protein 4.1, and actin, are associated with anaemia in HS. Increased anion-transporter or lowered protein 4.2 may be useful for diagnosis of HS, and were inherited in five out of six families where two generations were available.

Actins↗

PubMed1993

[Autologous bone marrow transplantation in children].

Autologous bone marrow transplantation is used for children with cancers which are only partially responsive to bone marrow toxic doses of cancer chemotherapy and irradiation. The use of megatherapy and autologous bone marrow transplantation instead of conventional doses for children has yielded substantial benefits in B-cell lymphoma, relapse of leukaemia, disseminated neuroblastoma and germ cell tumors. In the case of Wilms' tumor, rhabdomyosarcoma, osteosarcoma and Ewing's sarcoma with a partial initial response or a relapse, autologous bone marrow transplantation has been used to a limited extent. Based on the best results from conventional therapy and autologous bone marrow transplantation, respectively, the present need for autologous bone marrow transplantation in Denmark is estimated to be 24 transplantations a year.

Bone Marrow Transplantation↗

PubMed1993

[Autologous bone marrow transplantation in children with malignant diseases. Bone marrow harvest and procedure-related toxicity].

The aim of this paper was to present the results of bone marrow harvest followed by cryopreservation in 22 children with various malignant diseases, and the clinical course of autologous bone marrow transplantation (ABMT) performed in 10 children (three with acute lymphoblastic leukemia (ALL), three with acute myeloblastic leukemia (AML) and four neuroblastoma stage IV (NB)). In 20/22 children the harvested bone marrow contained a sufficient number of granulocyte-macrophage-colonyforming units (GM-CFU) for later marrow reinfusion. Hematological reconstitution was obtained in all 10 children who underwent ABMT. No child died of toxicity. The median time to neutrophil count > 0.5 x 10(9)/l, thrombocyte count > 50 x 10(9)/l and to discharge from hospital were 34, 49 and 29 days respectively. Five children are alive with no evidence of active disease 11-21 months after ABMT. Five children have suffered relapse and have died. It was concluded that sufficient amounts of precursor bone marrow cells may be harvested in children during a pause in cystostatic therapy. The acute toxicity of ABMT in children with malignant diseases was only moderate.

Adolescent↗

PubMed1993

Synergistic and antagonistic effects of myeloid growth factors on in vitro cellular killing by cytotoxic drugs.

The effect of stimulating acute myeloid leukemia blast cells with a combination of growth factors (G-CSF, GM-CSF, and IL-3) on cellular resistance to the antileukemia drugs Ara-C, daunorubicin, aclarubicin, and mitoxantrone was studied. For assessment of in vitro cellular drug resistance the MTT assay was employed. Stimulated cells showed enhanced sensitivity to Ara-C (p < 0.02), whereas a significant increase in cellular drug resistance to daunorubicin (p < 0.02) was observed. Variable and statistically non-significant changes in drug resistance to aclarubicin and mitoxantrone was induced by stimulation of the blast cells. We conclude on the basis of these observations that myeloid growth factors should be used with caution in combination with daunorubicin in AML treatment until further confirmatory evidence has been presented by other investigators.

Aclarubicin↗

PubMed1991

[Screening for neuroblastoma in infants aged 6 months. A method of testing].

In a number of cases, neuroblastoma (NB) may be diagnosed by routine screening of the urine for vanillinic-mandelic acid (VMA) and homovanillinic acid (HVA) in symptomfree infants at the age of six months. Early diagnosis of this disease may possibly improve the prognosis. The object of this project was to establish a method of measuring VMA and HVA concentrations in urine collected on filter paper and to assess participation by the parents as regards three different methods of collecting urine with the object of establishing a population screening programme for NB in Denmark. A total of 1,111 infants aged 6-8 months participated in the investigation. The equipment for testing the urine was given in three different was: 1) By the health nurses (County of Arhus), 2) By the general practitioner at the 6-month vaccination (County of Ringkøbing) and 3) By post (County of Viborg). In Arhus, the health nurses delivered the equipment to 96.7% of the age group concerned. Altogether, urine samples were obtained from 673 infants (61%). Participation was greatest in the County of Arhus (66%) and the County of Ringkøbing (62%) and lowest in the County of Viborg (54%). Two infants were found with marginally raised VMA or HVA but these values were found to be normal on repeated examinations. No cases of neuroblastoma were found in the material nor in the screened group in the course of 1 1/2 years after the conclusion of the investigation. In just over 3% of the cases, renewed urine samples had to be sent on account of too little urine on the filter paper. If current population investigations reveal that screening for neuroblastoma can alter the course of the disease in children, the method described here may form the basis for introduction of population investigations in Denmark.

Denmark↗

PubMed1991

Reproduction following treatment for childhood leukemia: a population-based prospective cohort study of fertility and offspring.

Of all children diagnosed with leukemia in Denmark, Finland, Iceland, Norway, and Sweden, 981 had discontinued therapy before 1985 and had been followed up annually after cessation of therapy. Progeny was registered and fertility evaluated among survivors who passed age 18 years without a relapse (n = 299). By April 1989, 48 offspring were registered, one of whom had congenital anomalies. This was no more than expected from the incidence of birth defects in the general population. No childhood malignancies or genetic diseases have so far been diagnosed in the progeny. In the study group, none of the 19 female and 8 male survivors of myeloid leukemias had become parents, and only 4 fathers were reported among the 131 male survivors of acute lymphoblastic leukemia (ALL). However, 23 of the 149 females treated for ALL had delivered 41 children. Fertility was measured as cumulative rates of first birth by maternal age. In a Cox regression analysis, cases who had received prophylactic radiation of the central nervous system (CNS) had a lower first birth rate than those without radiation (rate ratio 0.39, 95% CI 0.15-1.00), indicating that doses of 18-24 Gy to the brain may possibly be a risk factor. By using the Norwegian birth cohort of 1966 as a control group, matching the median year of birth for the study subjects, the group of female ALL survivors as a whole was as likely as the general female population to have given birth up to the age of 23. The first generation of females successfully treated for childhood ALL seems to have a nearly normal reproductive pattern during young adulthood, without increased risk of congenital anomalies in the offspring. However, cranial radiation as CNS prophylaxis may possibly impair subsequent reproduction.

Adolescent↗

PubMed1989

[Psychological follow-up study of families of children with acute lymphoblastic leukemia].

The qualities of the multi-disciplinary social, psychological, medical and nursing contributions for children diagnosed consecutively as having acute lymphoblastic leukaemia and their families were investigated. The parents of a total of 39 children, 31 fathers and 36 mothers, participated in a semi-structured interview with the psychologist attached to the department concerning the extent to which the psycho-social requirements of the family had been met by offers from the hospital. The interview concerning the diagnosis took place equally frequently in local hospitals and in Rigshospitalet. In both of these locations only half of the parent couples were satisfied with the course of the conversation. In the course of the disease, the mothers and the fathers experienced three situations differently: the situation at work, the parents' married life and the responsibility for treatment of the child. The family dynamic situation was altered in all of the families. Parents developed a closer relationship to the sick child while the relationship to the siblings equally frequently improved or deteriorated. At the conclusion of treatment, 2/3 felt that a form of security disappeared even though they were pleased to have got so far. In cases with relapse, another crisis developed and was just as difficult as the first, regardless of whether attempts had been made to prepare the families for this possibility. This investigation has pointed out a series of circumstances which the therapeutic system should be familiar with and which they can be prepared for.

Adolescent↗

PubMed1989

[Histiocytosis syndrome in children].

The recommended classification of the histiocytosis syndromes in children is as follows: 1. Langerhans' cell histiocytoses. 2. histiocytoses of mononuclear phagocytes. 3. neoplastic histiocytoses. The previous term, histiocytosis X, including eosinophilic granuloma of bone, the Hand-Schüller-Christian syndrome and Letterer-Siwe's disease, is now more correctly called Langerhans' cell histiocytosis (LCH) since the infiltrating cell in histiocytosis X both histologically and immunophenotypically is identified as the Langerhans' cell. Local and generalized LCH differmarkedly with respect to treatment and outcome. It is therefore necessary to perform an extensive investigation at the time of the initial evaluation of the patient. The most common mononuclear phagocytic syndromes are the familial erythrophagocytic lymphohistiocytosis and infection-associated or reactive hemophagocytic syndromes. The pathognomonic cell in familial erythrophagocytic lymphohistiocytosis is possibly a hybrid phenotype sharing characteristics of the two main types the mononuclear phagocyte system - i.e. the Langerhans' cells and phagocytic macrophages. Malignant histiocytosis is rarely seen in children and is a form of the Ki-1 positive anaplastic cell lymphoma.

Child↗

PubMed1989

Late relapses after treatment for acute lymphoblastic leukemia in childhood: a population-based study from the Nordic countries.

Seven late relapses of acute lymphoblastic leukemia occurring 5.5 to 12.3 years after cessation of therapy are reported in 986 patients who had discontinued treatment for leukemia acquired before the age of 15. The study covers patients from the five Nordic countries. Of the 434 patients with ALL who had passed 5 years of follow-up without recurrence, seven have subsequently relapsed so far; an estimated cumulative proportion of 6.9% within the 10 years. In addition, we report a girl 15.9 years old at diagnosis who relapsed 7.3 years after cessation of therapy. These findings confirm that "cure" of acute lymphoblastic leukemia treated in the 1970s cannot be considered definite, even 5 years after discontinuation of therapy.

Adolescent↗