PubMed Health⌕ Search

Biomedical subjects

A Toren

Publications and source records attributed to A Toren.

At least 19 recordsLinked to original sources
PubMed2007

Fiberoptic bronchoscopy and bronchoalveolar lavage for the evaluation of pulmonary disease in children with primary immunodeficiency and cancer.

BACKGROUND: Patients with childhood cancer or primary immunodeficiencies (PID) are at high risk for developing pulmonary infections and non-infectious complications. The broad differential diagnoses and the critical condition of these patients often drive physicians to start broad-spectrum antibiotic therapy before a definite diagnostic procedure is performed. A definite diagnosis may be achieved in these situations by fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL). PATIENTS AND METHODS: The records of 58 PIDs and cancer (immunocompromised group) pediatric patients who underwent 62 fiberoptic bronchoscopies between 2000 and 2004 were retrospectively reviewed and compared to 158 non-cancer patients who underwent 182 fiberoptic bronchoscopies during the same period. RESULTS: The overall diagnostic rate achieved by macroscopic inspection of purulent secretions or hemorrhage, abnormal cell count, and infectious agent isolation in the immunocompromised patients was 84%. A definite organism was recovered in 53.2% of the patients. Probable infection defined as purulent secretions or abnormal cell count without infectious agent isolation was diagnosed in another 21% of the patients. The rate of complications was 30.6%. In the control group, the overall diagnostic rate was 76.9% (n.s) and an infectious agent was demonstrated in 12.1% (P < 0.001). Probable infection was diagnosed in 24.2% (n.s) while the rate of complications was lower (15%) (P < 0.01). CONCLUSIONS: Rapid and accurate diagnoses were achieved in most procedures performed on immunocompromised patients. Although the rate of complications was higher in the immunocompromised group, they were usually very mild with no mortality. Based on these results, broncoalveolar lavage should be considered as an initial diagnostic tool in pediatric immunocompromised patients with pulmonary complications.

Adolescent↗
PubMed2004

Multilineage hematopoietic engraftment after allogeneic peripheral blood stem cell transplantation without conditioning in SCID patients.

Successful stem cell transplantation for patients with severe combined immunodeficiency (SCID) from matched family donors without conditioning results in engraftment of T lymphocytes. B lymphocytes engraft in only 50% of the cases, while myelopoiesis and erythropoiesis remain of host origin. Full hematopoietic engraftment was reported in one case after bone marrow transplantation without conditioning for a SCID patient. We studied three SCID patients who were transplanted with unmodified mobilized peripheral blood from HLA-identical family sex-mismatched members. They received megadoses of stem cells (18-23 x 10(6)CD34/kg). In contrast to the expected mixed chimerism that usually occurs in the absence of conditioning, we found in our patients 100% donor cell engraftment based on fluorescence in situ hybridization (FISH) and microsatellite techniques. Subset analysis of the engrafted cells using a multiparametric system enabling a combined analysis of morphology, immunophenotyping and FISH showed that both T and B lymphocytes and myeloid cells were of donor origin in two patients, while T lymphocytes and myeloid cells were of donor origin in the third. In the two cases with ABO incompatibility, erythroid engraftment was evidenced by blood group conversion from recipient to donor type. Multilineage donor engraftment is possible in SCID patients even without conditioning.

B-Lymphocytes↗
PubMed2004

Detection of RAG mutations and prenatal diagnosis in families presenting with either T-B- severe combined immunodeficiency or Omenn's syndrome.

It has been recently shown that mutations in both of the recombination activating genes RAG1 and RAG2 are involved in each of the two different types of severe combined immunodeficiency (SCID) syndromes: T-B- SCID and Omenn's syndrome (OS). The objective of the study was to search for novel mutations in the RAG genes and to offer prenatal diagnosis for families that have been identified as at risk of T-B- SCID or OS. Mutation analyses of polymerase chain reaction products of RAG1/RAG2 genes were performed in 14 cases (T-B- SCID = 6 and OS = 8). Consanguinity was reported in seven (50%) families. Four missense mutations in the RAG2 gene in six of eight OS patients and in four of six T-B- SCID patients were detected. The C1845T transition leading to a Tre215Ile substitution is a novel mutation. All but one of the patients were homozygous for the detected mutations, possibly reflecting the consanguinity in these families and the relative rarity of the disease-causing mutations. In addition, three putative polymorphic sites were found. Prenatal diagnosis was offered to seven families, but three of them declined genetic counseling for religious reasons. In the remaining families, four pregnancies were successfully completed, and in one case, the family chose to have an abortion because of a homozygous mutation. Mutations in RAG1/RAG2 genes were detected in only some of the T-B- SCID or OS patients, and the molecular basis for the remaining cases has yet to be elucidated. Important factors such as religious beliefs need to be considered when offering prenatal diagnosis to certain families.

Adult↗
PubMed2003

Tetraploid myeloid cells in donors of peripheral blood stem cells treated with rhG-CSF.

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is frequently used to mobilize CD34+ cells in healthy donors and patient with malignant diseases prior to peripheral blood stem cell (PBSC) harvest. To analyze the effects of rhG-CSF on morphology and genotype of white blood cells, a novel multiparametric cell scanning system that combines morphologic, immune and genotypic analyses of the same cells was used. We report here that tetraploid myeloid cells are present in the peripheral blood of donors treated with rhG-CSF. The tetraploidy was detected in up to 0.6% of differentiated myeloid cells and all observed CD34+ cells were diploid. Thus, short treatment with rhG-CSF of PBSC donors induces numerfical chromosomal alterations in a small subset of mature myeloid cells.

Case-Control Studies↗
PubMed2003

B-cell lymphoma developing in the donor 9 years after donor-origin acute myeloid leukemia post bone marrow transplantation.

Donor-cell leukemia post bone marrow transplantation is a rare event. Most of the cases reported to date have developed in cells from an HLA-matched sibling, who had no evidence of malignant disease before or following the occurrence of donor-origin leukemia. We describe a 17-year-old female who developed B-cell lymphoma 9 years following the occurrence of donor-origin acute myeloid leukemia in her brother for whom she had donated marrow. Cytogenetic analysis of the tumor revealed multiple chromosomal aberrations. The donor was heterozygous for the Ashkenazi mutation of Bloom's syndrome, suggesting that donor-type leukemia could have resulted from genomic instability in the donor cells.

Adolescent↗
PubMed2002

Solubilization of polyaromatic hydrocarbons by recombinant bioemulsifier AlnA.

AlnA is the protein responsible for the emulsifying and solubilizing activity of the Acinetobacter radioresistens KA53 bioemulsifier alasan. AlnA was produced in Escherichia coli, purified to homogeneity and then used to measure the enhanced solubility of 12 polyaromatic hydrocarbons (PAHs). The amount of PAH solubilized was directly proportional to AlnA concentration. The ratio of PAH solubilized by 40 micro g/ml AlnA compared to that soluble in the aqueous buffer varied greatly, from 4 (fluorene) to 81 (hexylbenzylcyclosilane). Calculations of moles PAH solubilized per mole AlnA yielded values from 4.3 (hexylphenylbenzene) to 55.8 (1,10-phenanthrolene). There was no obvious relationship between the amount of PAH solubilized and its molecular weight or intrinsic solubility. Native gel electrophoresis indicated that AlnA formed hexamers in the presence of PAHs. With molar ratios of fluorene to AlnA of 0.75 or less, only the monomer was observed, whereas at ratios of 7.5 or higher, only the hexamer was detected. At an intermediate molar ratio of 2.6, both monomer and hexamer appeared. The data indicate that PAHs are initially solubilized by binding to the monomeric form of AlnA, and as the amount bound increases above one molecule PAH per AlnA, the protein aggregates to form a specific oligomer of 5-8 monomers which allows for the binding and solubilization of more PAH.

Acinetobacter↗
PubMed2001

Nonmuscle myosin heavy chain IIA mutations define a spectrum of autosomal dominant macrothrombocytopenias: May-Hegglin anomaly and Fechtner, Sebastian, Epstein, and Alport-like syndromes.

May-Hegglin anomaly (MHA) and Fechtner (FTNS) and Sebastian (SBS) syndromes are autosomal dominant platelet disorders that share macrothrombocytopenia and characteristic leukocyte inclusions. FTNS has the additional clinical features of nephritis, deafness, and cataracts. Previously, mutations in the nonmuscle myosin heavy chain 9 gene (MYH9), which encodes nonmuscle myosin heavy chain IIA (MYHIIA), were identified in all three disorders. The spectrum of mutations and the genotype-phenotype and structure-function relationships in a large cohort of affected individuals (n=27) has now been examined. Moreover, it is demonstrated that MYH9 mutations also result in two other FTNS-like macrothrombocytopenia syndromes: Epstein syndrome (EPS) and Alport syndrome with macrothrombocytopenia (APSM). In all five disorders, MYH9 mutations were identified in 20/27 (74%) affected individuals. Four mutations, R702C, D1424N, E1841K, and R1933X, were most frequent. R702C and R702H mutations were only associated with FTNS, EPS, or APSM, thus defining a region of MYHIIA critical in the combined pathogenesis of macrothrombocytopenia, nephritis, and deafness. The E1841K, D1424N, and R1933X coiled-coil domain mutations were common to both MHA and FTNS. Haplotype analysis using three novel microsatellite markers revealed that three E1841K carriers--one with MHA and two with FTNS--shared a common haplotype around the MYH9 gene, suggesting a common ancestor. The two new globular-head mutations, K371N and R702H, as well as the recently identified MYH9 mutation, R705H, which results in DFNA17, were modeled on the basis of X-ray crystallographic data. Altogether, our data suggest that MHA, SBS, FTNS, EPS, and APSM comprise a phenotypic spectrum of disorders, all caused by MYH9 mutations. On the basis of our genetic analyses, the name "MYHIIA syndrome" is proposed to encompass all of these disorders.

Amino Acid Sequence↗
PubMed2001

Mutation analysis of the FAS and TNFR apoptotic cascade genes in hematological malignancies.

OBJECTIVE: The existence of properly functioning apoptotic pathways is of utmost importance in the maintenance of a normal cell count. Several groups have searched for mutations in the FAS receptor, a well-characterized apoptotic protein carrying a death domain, and reported the existence of rare mutations in multiple myeloma, T-acute lymphoblastic leukemia (T-ALL), and adult T-cell leukemia. Our aim was to expand these searches by looking for mutations in the death domains of FAS, FADD, TNFR, TRADD, and RIP, in the promoter region of FAS, and in the protease domain of caspase 10, in a larger variety of hematological malignancies, some of which express an apoptosis-resistant phenotype. METHODS: We extracted RNA and DNA samples from 92 hematological malignancies: chronic lymphocytic leukemia (CLL; 31 cases), chronic myelogenous leukemia (CML; 28 cases), essential thrombocythemia (ET; 8 cases), acute lymphocytic leukemia (ALL; 6 cases), acute myeloblastic leukemia (AML; 6 cases), hairy-cell leukemia (HCL; 3 cases), Burkitt's lymphoma (3 cases), polycythemia vera (PV; 3 cases), myelofibrosis (2 cases), and chronic myelomonocytic leukemia (CMML; 2 cases) and performed PCR-SSCP and sequence analysis on these samples. RESULTS: Five polymorphic patterns were found: three in the death domain of the FAS gene in CML patients, one in the promoter of this gene in a CLL patient, and the fifth in the death domain of the TRADD gene in a CML patient. No mutations, altering amino acids, were found in these genes in any of the aforementioned malignancies. CONCLUSIONS: These observations imply that mutations in the death domains of FAS, FADD, TNFR, TRADD, and RIP and in the protease domain of caspase 10 are not a major cause for failure of apoptosis in hematological malignancies, mainly CML and CLL. Regulatory and epigenetic abnormalities in these apoptotic cascade members and aberrations in other components of all death machinery should be looked for.

Apoptosis↗
PubMed2001

CMV reactivation induced BK virus-associated late onset hemorrhagic cystitis after peripheral blood stem cell transplantation.

Hemorrhagic cystitis (HC) is a known complication of stem cell transplantation. In contrast to early-onset HC that is usually attributed to cyclophosphamide and occurs within a few days of infusion, late onset HC is associated with viral infection. In recent years BK virus has emerged as an important causative agent. We describe two patients who developed late onset HC (38 and 92 days post transplant) associated with BK viruria concomitant with CMV reactivation and suggest a possible role of CMV in the process of BK virus DNA replication.

BK Virus↗
PubMed2001

Acute respiratory distress syndrome in children with malignancy--can we predict outcome?

PURPOSE: The purpose of this study was to delineate early respiratory predictors of mortality in children with hemato-oncology malignancy who developed acute respiratory distress syndrome (ARDS). MATERIALS AND METHODS: We conducted a retrospective chart review of children with malignant and ARDS who needed mechanical ventilation and were admitted to a pediatric intensive care unit from January 1987 to January 1997. RESULTS: Seventeen children with ARDS and malignancy aged 10.5 +/- 5.1 years were identified. Six of the 17 children (35.3%) survived. Sepsis syndrome was present in 70.6% of all the children. Peak inspiratory pressure, positive end-expiratory pressure (PEEP), and ventilation index values could distinguish outcome by day 3. A significant relationship between respiratory data and outcome related to efficiency of oxygenation, as determined by PaO(2)/FIO(2) and P(A-a)O(2), was present from day 8 after onset of mechanical ventilation. CONCLUSIONS: Peak inspiratory pressure, PEEP, and ventilation index values could distinguish survivors from nonsurvivors by day 3. This may assist in early application of supportive nonconventional therapies in children with malignancy and ARDS.

Adult↗
PubMed2001

Successful pregnancy after high-dose cyclophosphamide and ifosfamide treatment in two postpubertal women.

Alkylating agents, especially cyclophosphamide, are known to have a destructive effect on the ovaries and to result in sterility in many young women treated with these drugs. This is especially true when the treatment is given to postpubertal women. The authors describe 2 postpubertal women aged 16 and 25 suffering from Ewing sarcoma who were treated with the very aggressive Sloan-Kettering protocol, which includes high-dose cyclophosphamide and ifosfamide in addition to other drugs. Both women had spontaneous pregnancies and delivered normal babies. The significance of these cases in view of the experimental various reproductive preservation measures offered to such women is discussed.

Adolescent↗
PubMed2001

Emulsifying activities of purified Alasan proteins from Acinetobacter radioresistens KA53.

The bioemulsifier of Acinetobacter radioresistens KA53, referred to as alasan, is a high-molecular-weight complex of polysaccharide and protein. The emulsifying activity of the purified polysaccharide (apo-alasan) is very low. Three of the alasan proteins were purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had apparent molecular masses of 16, 31, and 45 kDa. Emulsification assays using the isolated alasan proteins demonstrated that the active components of the alasan complex are the proteins. The 45-kDa protein had the highest specific emulsifying activity, 11% higher than the intact alasan complex. The 16- and 31-kDa proteins gave relatively low emulsifying activities, but they were significantly higher than that of apo-alasan. The addition of the purified 16- and 31-kDa proteins to the 45-kDa protein resulted in a 1.8-fold increase in the specific emulsifying activity and increased stability of the oil-in-water emulsion. Fast-performance liquid chromatography analysis indicated that the 45-kDa protein forms a dimer in nondenaturing conditions and interacts with the 16- and 31-kDa proteins to form a high-molecular-mass complex. The 45-kDa protein and the three-protein complex had substrate specificities for emulsification and a range of pH activities similar to that of alasan. The fact that the purified proteins are active emulsifiers should simplify structure-function studies and advance our understanding of their biological roles.

Acinetobacter↗
PubMed2000

Autosomal-dominant giant platelet syndromes: a hint of the same genetic defect as in Fechtner syndrome owing to a similar genetic linkage to chromosome 22q11-13.

Families with 3 different syndromes characterized by autosomal dominant inheritance of low platelet count and giant platelets were studied. Fechtner syndrome is an autosomal-dominant variant of Alport syndrome manifested by nephritis, sensorineural hearing loss, and cataract formation in addition to macrothrombocytopenia and polymorphonuclear inclusion bodies. Sebastian platelet syndrome is an autosomal-dominant macrothrombocytopenia combined with neutrophil inclusions that differ from those found in May-Hegglin syndrome or Chediak-Higashi syndrome or the Dohle bodies described in patients with sepsis. These inclusions are, however, similar to those described in Fechtner syndrome. Other features of Alport syndrome, though, including deafness, cataracts, and nephritis, are absent in Sebastian platelet syndrome. Epstein syndrome is characterized by macrothrombocytopenia without neutrophil inclusions, in addition to the classical Alport manifestations-deafness, cataracts, and nephritis-and it is also inherited in an autosomal-dominant mode. We mapped the disease-causing gene to the long arm of chromosome 22 in an Italian family with Fechtner syndrome, 2 German families with the Sebastian platelet syndrome, and an American family with the Epstein syndrome. Four markers on chromosome 22q yielded an LOD score greater than 2.76. A maximal 2-point LOD score of 3.41 was obtained with the marker D22S683 at a recombination fraction of 0.00. Recombination analysis placed the disease-causing gene in a 3.37-Mb interval between the markers D22S284 and D22S693. The disease-causing gene interval in these 3 syndromes is similar to the interval described recently in an Israeli family with a slightly different Fechtner syndrome than the one described here. Recombination analysis of these 3 syndromes refines the interval containing the disease-causing gene from 5.5 Mb to 3.37 Mb. The clinical likeness and the similar interval containing the disease-causing gene suggest that the 3 different syndromes may arise from a similar genetic defect.

Bernard-Soulier Syndrome↗
PubMed2000

Amplification of immunological functions by subcutaneous injection of intermediate-high dose interleukin-2 for 2 years after autologous stem cell transplantation in children with stage IV neuroblastoma.

BACKGROUND: Immunotherapy given post-autologous stem cell transplantation may eliminate residual tumor cells escaping the conditioning protocol. METHODS: Five children suffering from stage IV neuroblastoma were treated by recombinant interleukin-2 (IL-2) post-autologous peripheral blood stem cell transplantation. The patients' peripheral mononuclear cells were monitored for CD3+ and CD56+ levels, their proliferative response and killing of various cell lines targets. RESULTS: An increase in the level of total lymphocytes, mainly due to expansion of T cells, and enhanced proliferative response to phytohemaglutinin were observed. Elevated cytotoxicity against K562 and neuroblastoma target cells was detected in four patients and against K562 targets in one patient. Toxicity included mild thrombocytopenia, and fever in four patients and mild to moderate encephalopathy which necessitated withdrawing one patient from the protocol. Three of five patients studied are alive today, one of them whose IL-2 was stopped, is in relapse. Two patients have died. CONCLUSIONS: Immunotherapy with s.c. intermediate-high dose IL-2 is feasible and results in expansion of T cells and in stimulation of killing activity against several targets including in some cases, neuroblastoma tumor cells.

Child, Preschool↗
PubMed2000

The risk for cancer among children of women who underwent in vitro fertilization.

BACKGROUND: The possible association between ovarian carcinoma and ovulation-inducing drugs has led to renewed interest in the potential carcinogenic risks of these drugs. In vitro fertilization (IVF) has been linked to multiple pregnancies and possibly congenital malformations. However, to the authors' knowledge the association between IVF and pediatric cancer has been described only in sporadic case reports. The aim of this study was to assess the incidence rate of pediatric cancer among a cohort of children born after IVF. METHODS: A historic prospective study based on a cohort of 332 children from 1254 women who underwent IVF treatment between 1981-1994 was performed. Medical files were reviewed and names were linked to the National Population and Cancer Registries. Pediatric cancer incidence rates were compared with the expected age-adjusted rates of the general population during the respective time period. RESULTS: No cancer cases were observed among the study cohort with respect to 1.7 cases that were expected. CONCLUSIONS: Because the small cohort analysis in the current study lacked the necessary power to reach definite conclusions, larger prospective studies are needed to assess the potential carcinogenic effect on children born after ovulation induction and IVF.

Adult↗
PubMed2000

Successful treatment of invasive aspergillosis in chronic granulomatous disease by granulocyte transfusions followed by peripheral blood stem cell transplantation.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder characterized by impaired microbial killing and susceptibility to bacterial and fungal infections. Cure of the disease can be achieved by stem cell transplantation when performed early in its course, and before severe infections have developed. Invasive aspergillosis constitutes a very high risk for transplantation. We report a 4-year-old boy with X-linked CGD who underwent successful HLA-identical peripheral blood stem cell (PBSC) transplantation during invasive pulmonary aspergillosis and osteomyelitis of the left fourth rib, which was unresponsive to antifungal treatment. During the 2 months prior to the transplant he received G-CSF-mobilized granulocyte transfusions (GTX) from unrelated donors three times a week in addition to the antifungal treatment. This resulted in clinical improvement in his respiratory status. He also received GTX during the aplastic period after the conditioning regimen, until he had engrafted. Post-transplant superoxide generation test revealed that neutrophil function was within normal range. One year post transplant the CT scan showed almost complete clearance of the pulmonary infiltrates and a marked improvement in the osteomyelitic process. Based on other reports and our own experience, GTX can serve as important treatment in patients with CGD who have failed conventional anti-fungal treatment and for whom stem cell transplantation is the only chance for cure.

Amphotericin B↗
PubMed1999

A photodynamic pathway to apoptosis and necrosis induced by dimethyl tetrahydroxyhelianthrone and hypericin in leukaemic cells: possible relevance to photodynamic therapy.

The mechanism of cell death induction by dimethyl tetrahydroxyhelianthrone (DTHe), a new second-generation photodynamic sensitizer, is analysed in human leukaemic cell lines in comparison with the structurally related hypericin. DTHe has a broad range of light spectrum absorption that enables effective utilization of polychromatic light. Photosensitization of HL-60 cells with low doses of DTHe (0.65 microM DTHe and 7.2 J cm(-2) light energy) induced rapid apoptosis of > or =90% of the cells. At doses > or =2 microM, dying cells assumed morphological necrosis with perinucleolar condensation of chromatin in HL-60 and K-562 cell lines. Although nuclear fragmentation that is characteristic to apoptosis was prevented, DNA digestion to oligonucleosomes proceeded unhindered. Such incomplete apoptosis was more prevalent with the related analogue hypericin throughout most doses of photosensitization. Despite hypericin being a stronger photosensitizer, DTHe exhibited advantageous phototoxic properties to tumour cells, initiating apoptosis at concentrations about threefold lower than hypericin. Photosensitization of the cells induced dissociation of the nuclear envelope, releasing lamins into the cytosol. DTHe also differed from hypericin in effects exerted on the nuclear lamina, causing release of an 86-kDa lamin protein into the cytosol that was unique to DTHe. Within the nucleus, nuclear envelope lamin B underwent covalent polymerization, which did not affect apoptotic nuclear fragmentation at low doses of DTHe. At higher doses, polymerization may have been extensive enough to prevent nuclear collapse. Hut-78, CD4+ cells were resistant to the photodynamically activated apoptotic pathway. Beyond the tolerated levels of photodynamic damage, these cells died exclusively via necrosis. Hut-78 cells overexpress Bcl-X(L) as well as a truncated Bcl-X(L)tr isoform that could contribute to the observed resistance to apoptosis.

Anthracenes↗