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P Riikonen

Publications and source records attributed to P Riikonen.

At least 37 records · Page 2Linked to original sources
PubMed1998

BTKbase, mutation database for X-linked agammaglobulinemia (XLA).

X-linked agammaglobulinemia (XLA) is an immunodeficiency caused by mutations in the gene coding for Bruton's agammaglobulinemia tyrosine kinase (BTK). A database (BTKbase) of BTK mutations has been compiled and the recent update lists 463 mutation entries from 406 unrelated families showing 303 unique molecular events. In addition to mutations, the database also lists variants or polymorphisms. Each patient is given a unique patient identity number (PIN). Information is included regarding the phenotype including symptoms. Mutations in all the five domains of BTK have been noticed to cause the disease, the most common event being missense mutations. The mutations appear almost uniformly throughout the molecule and frequently affect CpG sites that code for arginine residues. The putative structural implications of all the missense mutations are given in the database. The improved version of the registry having a number of new features is available at http://www. helsinki.fi/science/signal/btkbase.html

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1998

Serum N-terminal atrial natriuretic peptide (NT-ANP) in the cardiac follow-up in children with cancer.

BACKGROUND: We studied serum N-terminal atrial natriuretic peptide (NT-ANP) in children during and after chemotherapy for cancer to determine its applicability in detecting cardiac dysfunction. Forty-three patients were receiving chemotherapy for malignancy. Forty-eight patients were off chemotherapy and survived between 0.9 and 13 (median 5) years after the diagnosis, receiving cumulative anthracycline doses between 0 and 600 (median 225) mg/m2. PROCEDURE AND RESULTS: Cardiac evaluation of the patients included measurement of serum NT-ANP, recording of ECG, and assessment of systolic and diastolic function of the heart by echocardiography. During chemotherapy, serum NT-ANP levels were higher than in controls but varied markedly in the same individuals. Serum NT-ANP levels showed no consistent increase in the weeks following anthracycline administration. In late follow-up, serum NT-ANP levels were higher than in age-matched controls (median (range), 0.22 (0.06-0.47) vs. 0.14 (0.06-0.27) nmol/l, respectively, P < .001). The subgroup of patients with bone marrow transplantation and/or cardiac irradiation had the highest NT-ANP concentrations (0.30 (0.20-0.45) nmol/l). CONCLUSIONS: Thus, serum NT-ANP measurements seemed to represent a useful contribution in the long-term cardiac follow-up of children after cancer. This blood test can readily be included to laboratory follow-up, is reasonably inexpensive and may decrease the need for more laborious tests of cardiac function. When there is ongoing chemotherapy, NT-ANP levels are influenced by a variety of factors that invalidate its routine use during this period.

Adolescent↗
PubMed1998

Recommendations on the use of colony-stimulating factors in children: conclusions of a European panel.

UNLABELLED: During 1996 and 1997 a panel of European haematologists, oncologists, and neonatologists developed specific paediatric guidelines for the use of colony stimulating factors based on published literature and the clinical experience of these specialists within each of 13 countries. Well established indications for use comprise intervention in patients with life-threatening infection, adjunctive therapy post autologous bone marrow transplantation (BMT), mobilization of peripheral blood progenitor cells for autologous BMT, patients with acquired aplastic anaemia on anti-lymphocyte globulin and cyclosporin regimen, and severe congenital neutropenia. Less clear indications include primary prophylaxis to support dose intensification in children with high risk/advanced malignancies, secondary prophylaxis to prevent neutropenia in patients with a history of severe neutropenia, support therapy in cases of poor marrow function following BMT and for deteriorating marrow function following successful BMT, in neonatal sepsis and non infectious neonatal neutropenia, in drug induced neutropenia and in HIV-positive patients. Treatment is generally well tolerated and granulocyte colony stimulating factor appears better tolerated than granulocyte and macrophage colony stimulating factor. Economically colony stimulating factors have not been shown to induce excessive costs for a given patient. CONCLUSION: In general the adult guidelines are applicable to children but additional considerations (aggressive or very progressive childhood neoplasms, specific indications, neonatal use, congenital disorders) must be taken into account.

Bone Marrow Transplantation↗
PubMed1998

DNA copy number changes in childhood acute lymphoblastic leukemia.

BACKGROUND AND OBJECTIVE: Comparative genomic hybridization (CGH) allows the study of DNA copy number changes in a single hybridization from tumor DNA without any cell culture. Three reports of childhood acute lymphoblastic leukemia (ALL) studied by CGH have been published so far, with somewhat discrepant results. In the present study we performed CGH analysis on 36 patients with childhood ALL. The results were compared to those reported earlier on 157 cases. DESIGN AND METHODS: DNA was extracted from bone marrow specimens from 36 patients with childhood ALL. The tumor and reference DNAs were labeled with fluorescein-isothiocyanate conjugated dCTP and dUTP, and Texas red-conjugated dCTP and dUTP. The hybridizations were analyzed using the ISIS digital image analysis system. RESULTS: The most commonly gained chromosomes were X (42%), 4 (31%), 6 (31%), 10 (36%), 14 (28%) and 18 (33%), and the most common losses were at 9p22-pter (6%) and 12p13-pter (14%). INTERPRETATION AND CONCLUSIONS: The pattern of gains of DNA sequences was very similar in the four reports, but the 9p and 12p deletions were observed only in the present study and one previous report. Our review of the results of 193 patients studied so far shows that the success rate using CGH was close to 100%, whereas cytogenetic analysis failed to reveal any information in 21 patients (11%). Furthermore, in 69 (36%) out of 193 patients CGH gave additional information to the banding analysis. CGH should, therefore, be used to supplement standard cytogenetics in the analysis of childhood ALL patients.

Adolescent↗
PubMed1996

Granulocyte-colony-stimulating factor after allogeneic and autologous bone marrow transplantation in children.

We evaluated the use of granulocyte CSF (G-CSF) after both allogeneic BMT (allo-BMT) and autologous BMT (ABMT) in children. After allo-BMT, G-CSF was used in 15 children who were compared with 20 historical controls. The ABMT patients were two sequential groups: the G-CSF group of 13 children and 11 historical controls. The patients were conditioned with different high-dose chemotherapy regimens with or without total body irradiation. G-CSF was administered at 5 micrograms/kg/day s.c. and was continued until an absolute neutrophil count (ANC) of 1,000 x 10(6)/l was reached. Following allo-BMT, G-CSF accelerated myeloid engraftment with a difference of 5 days at the ANC level of 500 x 10(6)/l (P<0.02) and 9 days at 1,000 x 10(6)/l (P<0.001). In the ABMT patients, G-CSF also accelerated myeloid engraftment. The difference between the G-CSF group and the control group was 6 days at ANC 200 (P<0.05), 11 days at ANC 500 (P<0.02) and 17 days at ANC 1,000 (P<0.005). In the ABMT patients, benefit by G-CSF was also observed in a smaller number of days with fever and days on antibiotics. We conclude that G-CSG significantly accelerated myeloid engraftment, after both allogeneic and autologous BMT in children, and also decreased the duration of febrile illness in the ABMT patients.

Adolescent↗
PubMed1995

Evidence for functional polymorphism of the spvR gene regulating virulence gene expression in Salmonella.

The expression of Salmonella enterica spv virulence genes was studied in serovariants Dublin and Typhimurium using Western blotting (immunoblotting), spv-lacZ operon fusions and Northern blotting. The SpvA protein was detected in immunoblots from stationary phase cultures of Dublin but not from the corresponding cultures of Typhimurium. Transcriptional measurements, using a spvA-lacZ operon fusion, indicated 8-10 times higher spvA transcription in Dublin. In an isogenic Escherichia coli chromosomal background, virulence plasmids from various Dublin strains systematically had a significantly higher induction level of the spvA-lacZ operon fusion than virulence plasmids from Typhimurium strains. The cloned spvR transcriptional activator gene of Dublin strain 2229 was found to activate both spvR-lacZ and spvA-lacZ operon fusions, as well as to raise spv mRNA levels in E. coli TG1. In contrast, the corresponding cloned gene of Typhimurium strain SL2965 possessed a lower induction potential and required higher spvR gene dosage for activation. A comparison of the nucleotide sequences of spvR genes from two Dublin and four Typhimurium strains revealed conserved, serovariant-associated basepair substitutions. Our results indicate that the spv virulence gene cluster possesses different functional alleles of the regulator gene spvR. This finding has important consequences for comparative studies of regulation and virulence in different serovariants of Salmonella.

Base Sequence↗
PubMed1995

Recombinant human granulocyte-macrophage colony-stimulating factor in combination with antibiotics in the treatment of febrile neutropenia in children.

Fever and neutropenia are life-threatening complications of chemotherapy in children with cancer. Prompt initiation of empiric broad-coverage antimicrobial therapy at the first signs of fever has reduced the mortality rates to about 2-5%. However, myelosuppression with febrile neutropenia is the major dose-limiting side effect of anticancer chemotherapy, results in prolonged hospitalization, and frequently delays the scheduled cycles of chemotherapy. Prophylactic use of hematopoietic growth factors has been shown to reduce the incidence of fever and infectious complications in children with cancer and neutropenia. Therapeutic use of recombinant human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF) in combination with antibiotics in children with febrile neutropenia has also shown a clear beneficial effect. The number of hospital days due to treatment of febrile neutropenia, the number of days on broad-spectrum antibiotics and the duration of neutropenia were significantly reduced with the use of rHuGM-CSF. Importantly, rHuGM-CSF did not prolong the days with fever in children admitted with febrile neutropenia. In the treatment of documented fungal superinfection, it may be beneficial if rHuGM-CSF and an antifungal drug are used as combination therapy. rHuGM-CSF is non-toxic and well tolerated in children with cancer.

Anti-Bacterial Agents↗
PubMed1995

Prophylactic administration of granulocyte colony-stimulating factor (filgrastim) after conventional chemotherapy in children with cancer.

We evaluated granulocyte colony-stimulating factor (G-CSF) as an adjunct to courses of conventional chemotherapy in 16 children with cancer. One course followed by G-CSF (20 episodes) was compared to identical courses without G-CSF (20 episodes) in the same patients. The mean duration of G-CSF therapy was 8.8 (5-13) days. The periods of neutropenia (4.8 days versus 16.5 days; p < 0.0001), days of hospitalization for febrile neutropenia (13 days versus 65 days; p = 0.02) and days on broad-spectrum antibiotics (13 days versus 95 days; p = 0.003) were significantly reduced. With the use of G-CSF the profound neutropenia could be prevented in 11 (55%) episodes. There were two episodes of fever and neutropenia in the G-CSF group as compared to 10 febrile neutropenias in the control group (p = 0.04). G-CSF was well tolerated and did not cause additional expenses when compared to the expenses needed for the treatment of febrile neutropenias. The cost benefit analyses showed that through using G-CSF a savings was realized in the amount of U.S. $20,650 for 20 cycles of chemotherapy, i.e., U.S. $1,033/chemotherapy cycle. We conclude that the use of G-CSF was efficacious and did not increase the total costs of therapy.

Adolescent↗
PubMed1994

Accuracy of protein flexibility predictions.

Protein structural flexibility is important for catalysis, binding, and allostery. Flexibility has been predicted from amino acid sequence with a sliding window averaging technique and applied primarily to epitope search. New prediction parameters were derived from 92 refined protein structures in an unbiased selection of the Protein Data Bank by developing further the method of Karplus and Schulz (Naturwissenschaften 72:212-213, 1985). The accuracy of four flexibility prediction techniques was studied by comparing atomic temperature factors of known three-dimensional protein structures to predictions by using correlation coefficients. The size of the prediction window was optimized for each method. Predictions made with our new parameters, using an optimized window size of 9 residues in the prediction window, were giving the best results. The difference from another previously used technique was small, whereas two other methods were much poorer. Applicability of the predictions was also tested by searching for known epitopes from amino acid sequences. The best techniques predicted correctly 20 of 31 continuous epitopes in seven proteins. Flexibility parameters have previously been used for calculating protein average flexibility indices which are inversely correlated to protein stability. Indices with the new parameters showed better correlation to protein stability than those used previously; furthermore they had relationship even when the old parameters failed.

Antigens↗
PubMed1994

Recombinant human granulocyte-macrophage colony-stimulating factor in the treatment of febrile neutropenia: a double blind placebo-controlled study in children.

In a double blind study of 58 episodes of fever and profound neutropenia, children with cancer received either recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) or placebo, combined with identical antimicrobial therapy, i.e. imipenem, on admission. The criteria for discontinuation of therapy were identical. A difference was demonstrated both in the number of hospital days, totaling 252 days in the rhGM-CSF group and 354 in the placebo group, days receiving antibiotics (220 vs. 322), and in the resolution of neutropenia (4.5 days vs. 6.0 days; P < 0.05). The number of episodes requiring antimicrobial therapy for longer than 10 days was 5 of 28 (12%) in the rhGM-CSF group as opposed to 15 of 30 (50%) in the placebo group (P = 0.01). rhGM-CSF was well-tolerated. We conclude that rhGM-CSF was efficacious in accelerating myeloid recovery and reducing the length of hospitalization in febrile neutropenia.

Adolescent↗
PubMed1993

Transcriptional regulation of Salmonella enterica virulence plasmid genes in cultured macrophages.

The plasmid-carried spv genes promote virulence of salmonellae in mice by allowing bacterial growth in the reticuloendothelial tissue. When the bacteria are cultivated under normal laboratory conditions the spv genes appear dormant. This communication explores the transcriptional regulation of spv genes within murine macrophage-like J774-A.1 cells utilizing a new reporter system. Transcriptional fusions were constructed between promoter elements of the Salmonella enterica var. Typhimurium spv genes and the KS71A fimbrial gene cluster. The expression of KS71A fimbriae in fusion-carrying Escherichia coli strains was found to be under the control of the transcriptional activator gene spvR. In strains overproducing SpvR, KS71A fimbriae were assembled on the bacterial cell surface and could be detected by bacterial agglutination or immunofluorescence of intact bacteria; the reporter activity was quantified by estimating the percentage of fluorescent bacteria and by immunoblotting of cell lysates. The activity of the reporters, when transformed into the parent Typhimurium TML R66, was low and revealed less than 0.3% fimbriated cells under in vitro culture conditions. A 15-30-fold increase in fimbriation was observed when the bacteria were cultivated within J774-A.1 cells. No such increase occurred when the reporter fusions were transformed into TML R66 cured of the virulence plasmid. Insertional inactivation of the spvR gene of the virulence plasmid in Typhimurium TML R66 also abolished induction, whereas corresponding inactivation of spvA or spvB did not reduce induction. No increase in reporter activity was obtained in Typhimurium of line Q1, which is naturally avirulent for mice, although the strain was provided with virulence plasmid pEX102 of line TML R66. We conclude that the intracellular environment of J774-A.1 cells induces the spv genes and that this induction requires gene functions of both the bacterial chromosome and the virulence plasmid.

Animals↗
PubMed1993

Fever and neutropenia in children with cancer: diagnostic parameters at presentation.

We evaluated 91 episodes of fever in 46 profoundly neutropenic children with cancer, in a search for any symptom, sign or laboratory test that would serve to identify patients with septicemia and differentiate them from those in no immediate need of prompt antimicrobial therapy. Seventeen episodes (19%) were bacteremias, 59 (64%) were suspected septic infections, 9 (10%) were focal bacterial infections and 6 (7%) proved not to be bacterial infections. We were unable to detect any parameter, either on admission or after two days of antimicrobial therapy (except for blood culture findings), that would be helpful in differentiating bacteremia from an episode not of bacterial origin. We focused on serum levels of C reactive protein and found them unreliable on an individual level. Prompt institution of antimicrobial therapy at the occurrence of fever results in low mortality, but does not allow assignment of cases to different categories.

Adolescent↗
PubMed1993

Fever and neutropenia: bacterial etiology revealed by serological methods.

In a prospective study, 91 episodes of fever in neutropenic children with cancer were evaluated. Fifteen episodes were septicemias, verified by a positive blood culture, 62 were fevers of unknown origin, 6 were focal infections and 8 were of other etiologies (i.e. drug fevers and viral infections). Serum antibody responses to bacteria were measured in paired sera by an enzyme immunoassay method. Bacterial infection was demonstrated serologically in 20% of documented septicemias, in 35% of fevers of unknown origin and occasionally in the other groups. Tests were available and found positive in the fever of unknown origin group for Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella (Branhamella) catarrhalis and enterobacteria. Some had multiple etiology. In conclusion, bacterial serology is a promising method of identifying bacterial etiology in fever of otherwise unknown origin in neutropenic children with cancer.

Adolescent↗
PubMed1993

Management of indwelling central venous catheters in pediatric cancer patients with fever and neutropenia.

This prospective study comprises 97 episodes of fever and neutropenia in children with cancer and central venous access. In 76% of episodes, patients had a Broviac-Hickman-like catheter, and in 24% a totally implanted venous access chamber system. The need for catheter removal during a febrile infection was 0.32/1000 catheter days, and the documented sepsis rate was 0.59/1000 catheter days. Our data indicate that 94% of episodes of fever and neutropenia in total, 78% of documented septicemias, and 97% of fevers of unknown origin were curable with broad-coverage antimicrobial therapy without removing the central venous line. Totally implanted chambers had a lower infection rate than catheters of Broviac-Hickman type.

Adolescent↗