The use of PCR in the diagnosis of hyper-reactive malarial splenomegaly (HMS)

Between August 1997 and September 1998, 14 cases of hyper-reactive malarial splenomegaly (HMS) were diagnosed in the Instituto de Salud Carlos III in Madrid, Spain. These cases, from Equatorial Guinea and Cameroon, were identified using the diagnostic criteria established by Y. M. Fakunle in 1981: gross splenomegaly; high levels of anti-malarial antibodies; IgM in serum at least two standard deviations above the local mean; and clinical and immunological response to antimalarial treatment. Although malarial parasites were only detected in the Giemsa-stained blood films of four of the cases, these four and four others were found to have the DNA of such parasites in their blood when tested using a method based on a semi-nested, multiplex PCR. These result indicate that malarial parasitaemias may be more prevalent in HMS than is usually recognized.

Clinical and economic comparison of allogeneic peripheral blood progenitor cell and bone marrow transplantation for acute lymphoblastic leukemia in children

There is limited experience in the use of peripheral blood progenitor cells (PBPC) for allogeneic transplantation in children. In the present study we compared engraftment kinetics, incidence of acute and chronic graft-versus-host disease (GVHD) and the outcome and economic costs of allogeneic PBPCT vs BMT in children with ALL in a single institution. All children were transplanted in complete remission (CR) with a similar conditioning regimen and the same GVHD prophylaxis. Patients undergoing PBPCT achieved myeloid and platelet engraftment before patients undergoing BMT (P < 0.001). Platelet recovery was faster for the PBPCT group (P < 0.014 for 50 x 10(9)/l and P < 0.039 for 100 x 10(9)/l). Incidence and severity of acute and chronic GVHD were similar in both groups (acute grade 1-2: 9/13 for PBPCT vs 9/11 for BMT; chronic GVHD: 5/12 for PBPCT vs 3/8 for BMT). Hospital stay was shorter for the PBPCT than for the BMT group (28.8 days vs 42.9 days, respectively) and the PBPCT group used less clinical resources, resulting in overall lower cost for PBPCT (US $14,046) compared to BMT (US $19,840). There was no statistically significant difference in DFS between PBPCT and BMT (68.4% vs 50%, respectively).

Specific and rapid induction of the proapoptotic protein Hrk after growth factor withdrawal in hematopoietic progenitor cells

Hrk is a newly described proapoptotic member of the Bcl-2 family that is mainly expressed in hematopoietic tissues and cultured neurons. In this study we have examined the expression and activity of Hrk in hematopoietic progenitors. To address these issues, we used 3 growth factor-dependent murine hematopoietic cell lines, HCD-57, FDCP-Mix, and FL5.12. The expression of Hrk was undetectable in cells cultured with growth factors, but it was rapidly up-regulated on growth factor withdrawal. In contrast, the expression of Bcl-x(L) decreased and that of proapoptotic Bax, Bad, and Bak was unchanged or down-regulated after removal of growth factors. This pattern of expression correlated with the induction of apoptosis. Hrk was also up-regulated in human cell lines and in bone marrow-derived CD34(+) cells cultured in the absence of growth factors. In addition, the levels of Hrk were up-regulated after treatment with the chemotherapeutic drug etoposide. Expression of prosurvival Bcl-x(L) or Bcl-2 proteins blocked the induction of Hrk. Hrk was induced in FDCP-Mix cells treated with ionomicin in the presence of IL-3, suggesting that cytosolic calcium may regulate the expression of this proapoptotic protein. Furthermore, ectopic expression of Hrk induced cell death of hematopoietic progenitors in the presence of IL-3. Thus, Hrk is specifically and rapidly induced in hematopoietic progenitors after growth factor deprivation or treatment with chemotherapeutic drugs, and this may be sufficient to induce apoptosis in these cells. (Blood. 2000;95:2742-2747)

Blockade of the Bcr-Abl kinase activity induces apoptosis of chronic myelogenous leukemia cells by suppressing signal transducer and activator of transcription 5-dependent expression of Bcl-xL

Bcr-Abl-expressing leukemic cells are highly resistant to apoptosis induced by chemotherapeutic drugs. Although a number of signaling molecules have been shown to be activated by the Bcr-Abl kinase, the antiapoptotic pathway triggered by this oncogene has not been elucidated. Here, we show that the interleukin 3-independent expression of the antiapoptotic protein, Bcl-xL, is induced by Bcr-Abl through activation of signal transducer and activator of transcription (Stat)5. Inhibition of the Bcr-Abl kinase activity in Bcr-Abl-expressing cell lines and CD34(+) cells from chronic myelogenous leukemia (CML) patients induces apoptosis by suppressing the capacity of Stat5 to interact with the bcl-x promoter. Interestingly, after inhibition of the Bcr-Abl kinase, the expression of Bcl-xL is downregulated more rapidly in chronic phase than in blast crisis CML cells, suggesting an involvement of this protein in disease progression. Overall, we describe a novel antiapoptotic pathway triggered by Bcr-Abl that may contribute to the resistance of CML cells to undergo apoptosis.

p53 expression in locally advanced pharyngeal squamous cell carcinoma

BACKGROUND

Prognosis for advanced head and neck squamous cell carcinoma remains poor despite advances in treatment, although a small number of patients may benefit from induction therapy leading to increased local control. Mutations of the p53 gene, which are present in a considerable percentage of head and neck squamous cell carcinomas, have been associated with poor response to chemotherapy. The role of p53 protein overexpression (which is associated with p53 gene mutations) in predicting the response to chemotherapeutic agents and survival rates is not clear.

OBJECTIVE

To determine the association of p53 expression with chemotherapy response rates and disease-free survival rates in 62 patients with locally advanced pharyngeal cancer treated with induction cisplatin-5-fluorouracil chemotherapy between 1983 and 1995.

DESIGN

Historical cohort. Archival tissue from biopsies done before chemotherapy was immunohistochemically stained for the p53 tumor suppressor gene (clone D0-7; DAKO Corp, Glostrup, Denmark).

RESULTS

Positive staining for p53 occurred in 45 (73%) of 62 cases, with the percentage of reactive cells ranging from 35% to 98%. Chemotherapy response rates were higher in the p53-negative group (15/17 [88%]) compared with the p53-positive group (27/45 [60%]) (P =.07). The risk of recurrence was lower in the p53-negative group compared with the p53-positive group at 2, 3, and 5 years after treatment (P = .03, P = .01, and P = .007, respectively). The median relapse-free survival rates of patients in the p53-negative group was 16 months, whereas those with p53 protein expression demonstrated a median relapse-free survival time of 9 months (P = .07). In multivariate analyses, the only independent factor of relapse-free survival rates was age older than 70 years.

CONCLUSION

The present study shows a trend favoring p53 overexpression as a predictive and prognostic factor in locally advanced pharyngeal cancer treated with induction chemotherapy.

[Detection of p53 protein in advanced head and neck cancer]

P53 protein expression, synonymous to p53 gene mutation, is a common event in head and neck squamous cell carcinoma (HNSCC). However, the correlation between p53 expression and clinico-pathologic parameters remains unclear. Primary tumors for analysis were obtained from 99 patients with HNSCC. The expression of p53 was analyzed with monoclonal D07 antibody (Dako Corp., Glostrup, Denmark). Seventy five percent of 79 valid cases expressed the protein. A correlation was found between alcohol intake and p53 expression. None of the other clinico-pathologic factors were associated to p53 expression. Our results suggest that p53 may be involved in the development of HNSCC. However its clinical significance is still not completely understood.

alpha-Alkyl-alpha-Amino-beta-Lactam Peptides: Design, Synthesis, and Conformational Features

Remarkable asymmetric induction is achieved in the alkylation of the lithium enolate of the beta-lactam 1. This allows the first time access to a new family of peptidomimetics 2 with predictable conformational constraints.

Production of engineered human pancreatic ribonucleases, solving expression and purification problems, and enhancing thermostability

Human pancreatic ribonuclease, the homolog of bovine pancreatic ribonuclease, has a significant therapeutic potential. Its study has been hindered by the difficulty of obtaining the enzyme in a pure and homogeneous form, either from human source or using heterologous expression. Engineering of different variants of human pancreatic ribonuclease has allowed us to study and overcome some problems encountered during its heterologous production in an Escherichia coli system and its purification from inclusion bodies. The 5'-end region of the mRNA that encodes the enzyme is critical for obtaining high expression levels. The results also suggest the importance of the proline 50 residue in the recovery yields of human pancreatic ribonuclease. All the variants produced are pure and homogeneous. Their homogeneity has been demonstrated by cation-exchange and reversed-phase chromatography and by mass spectrometry analysis. Moreover, enhancement of human pancreatic ribonuclease thermal stability is observed when residues R4, K6, Q9, D16, and S17 are changed to the corresponding residues of bovine seminal ribonuclease.

Usefulness of seminested multiplex PCR in surveillance of imported malaria in Spain

The use of a new PCR-based method for the diagnosis of malaria in the Spanish Malaria Reference Laboratory has promoted an increase in confirmed cases of malaria. From August 1997 to July 1998, a total of 192 whole-blood samples and 71 serum samples from 168 patients were received from the hospitals of the Spanish National Health System. Most of the patients came from west-central African countries (85%). This molecular method showed more sensitivity and specificity than microscopy, detecting 12.4% more positive samples than microscopy and 13% of mixed infections undetectable by Giemsa stain. Plasmodium falciparum was the main species detected, with 68% of the total positive malaria cases, followed by Plasmodium malariae (29%), Plasmodium vivax (14%), and Plasmodium ovale (7%), including mixed infections in all cases. This report consists of the first wide, centralized survey of malaria surveillance in Spain. The reference laboratory conducted the analysis of all imported cases in order to detect trends in acquisition. The use of a seminested multiplex PCR permitted confirmation of the origins of the infections and the Plasmodium species involved and confirmation of the effectiveness of drug treatments. This PCR also allowed the detection of the presence in Spain of primaquine-tolerant P. vivax strains from west-central Africa, as well as the detection of a P. falciparum infection induced by transfusion.

Active concentration measurements of recombinant biomolecules using biosensor technology

Whereas the concentration of a biomolecule simply refers to the amount of chemical substance per unit of volume, its active concentration refers to a relational parameter that has meaning only with respect to the molecule's ability to interact specifically with one particular ligand. When proteins are studied in a biological context, it is the biologically active concentration that is relevant, and not the total concentration of correctly and incorrectly folded molecules. Using a biosensor instrument the concentration of active biomolecules in a preparation can be measured by injecting the preparation at different flow rates onto a sensor chip surface presenting a high concentration of a specific ligand. The method can be used under conditions of partial mass transport limitation and does not require a pre-established standard curve. When the method was used to measure the active concentration of several recombinant proteins it was found that the active concentration was much lower than the nominal concentration determined by conventional methods. The active concentration also depended on the ligand used in the binding assay, reflecting the fact that active concentration can only be defined with respect to one specific probe. Such discrepancies in concentration values, if undetected, may lead to erroneous conclusions regarding the properties and behaviour of recombinant proteins tested in different assays.

Limitations of percutaneous techniques in the treatment of portal vein thrombosis

New therapeutic alternatives to portal vein thrombosis (PVT) include the percutaneous, transhepatic infusion of fibrinolytic agents, balloon dilatation, and stenting. These maneuvers have proven to be effective in some cases with acute, recent PVT. We have treated two patients with acute PVT via transhepatic or transjugular approaches and by using pharmacologic and mechanical thrombolysis and thrombectomy. Although both patients clinically improved, morphologic results were only fair and partial rethrombosis was observed. The limitations of percutaneous procedures in the recanalization of acute PVT in noncirrhotic patients are discussed.

Horseshoe kidney presenting as a retroperitoneal mass. Report of a case diagnosed by fine needle aspiration cytology

BACKGROUND

Horseshoe kidney is a renal congenital anomaly. It is the result of the fusion of either upper or lower poles of both kidneys, appearing as a horseshoe-shaped structure. This anomaly is very frequent: it can be found in about 1 of every 50-1,000 autopsies).

CASE

Computed tomography performed routinely after pancreatitis in a 37-year-old female showed a retroperitoneal mass of uncertain origin. Fine needle aspiration cytology (FNAC) smears evidenced normal renal tissue. Urography confirmed the diagnosis of horseshoe kidney.

CONCLUSION

This is the first reported case of horseshoe kidney diagnosed by FNAC. It demonstrates the utility of FNAC for diagnosis of retroperitoneal masses, especially if they are asymptomatic.

Erythropoietin can induce the expression of bcl-x(L) through Stat5 in erythropoietin-dependent progenitor cell lines

Erythropoietin (Epo) initiates its cellular response by binding to the Epo receptor, which triggers the activation of signal transducer and activator of transcription (Stat) 5 protein. Cell culture studies of erythroid progenitors have suggested that Epo functions as a survival factor by repressing apoptosis at least in part through Bcl-x(L), an anti-apoptotic protein of the Bcl-2 family. In this report, we examine whether Stat5 can induce transactivation of the bcl-x gene in response to Epo. Two Epo-responsive progenitor cell lines, HCD-57 and Bcl-2-transfected Ba/F3-Epo receptor (Ba/F3-EpoR-Bcl-2), were used in this study. After Epo stimulation, we observed a correlation between expression of bcl-x(L) and activation of Stat5 as assessed by the expression of oncostatin M, a direct target of Stat5, and the phosphorylation and nuclear translocation of Stat5. Moreover, a Stat binding element in the bcl-x promoter was found to be active in response to Epo, a finding that was further confirmed because mutagenesis of this sequence motif abrogated its promoter activity and overexpression of a dominant negative Stat5 protein blocked transactivation. When DNA-protein binding analyses were performed, we found that Stat5, not Stat1 or Stat3, was the protein bound to the bcl-x promoter in response to Epo. These data suggest that Epo-dependent activation of Stat5 is a transcriptional pathway that can be used by Epo-responsive progenitor cells to induce the expression of bcl-x(L) and consequently to inhibit apoptosis.

Successful unrelated umbilical cord blood transplantation in a child with Omenn's syndrome

Omenn's syndrome is a variant of combined immunodeficiency disease (CID). Like other CID forms, it causes death unless the patient receives a bone marrow transplant (BMT). Previous reports have shown that BMTs from unrelated donors in Omenn's syndrome have very poor results, with a high rate of infections during transplantation and graft rejection, when compared with transplants from related donors or patients with other CID. This study discusses the case of a 19-month-old child with Omenn's syndrome, who received an unrelated cord blood stem cell transplant (CBT). Donor and recipient had 1 HLA-Ag mismatched on HLA-B. Symptomatology improved early after CBT. The child achieved leukocytes and platelet engraftment and was discharged on day +34. His follow-up has been uneventful and at this time, 27 months after CBT, immune functions have been recovered.

Indications for epiphyseal preservation in metaphyseal malignant bone tumors of children: relationship between image methods and histological findings

We compared several image methods in the evaluation of the possible physeal effect in 47 osteosarcomas and 18 Ewing's sarcomas in children. The minimal follow-up was 3 years (range, 3-17). In the histological study, the physis was affected in 53% of the cases. We correlated the histological findings and the findings from the different image methods. There were more false-positive than false-negative results, and in the computed tomography and magnetic resonance imaging (MRI) studies, there were no false negatives. The accuracy of MRI (predictive positive value plus predictive negative value) was the best (90.3%), and it is the technique that we prefer. According to these findings, we can safely preserve the epiphysis in cases of metaphyseal tumors showing no contact between the tumor and the growth plate in the MRI images. If the tumor shows contact with part of the physis, it is also possible to preserve the epiphysis.

[The prevalence of the Cys282Tyr mutation in the hemochromatosis gene in Cantabria in patients diagnosed with hereditary hemochromatosis]

BACKGROUND

The aim of our study was to evaluate the prevalence of Cys282Tyr mutation in patients with genetic haemochromatosis (GH) in Cantabria.

PATIENTS AND METHODS

The HFE Cys282Tyr mutation was determined in a cohort of 60 patients with GH and 213 controls.

RESULTS

The frequency of the Cys282Tyr mutation in control individuals was 4.4%. Sixty-seven percent of patients with GH were homozygous for the Cys282Tyr mutation. Twenty-seven percent of patients were normal at Cys282Tyr loci.

CONCLUSIONS

The prevalence of the Cys282Tyr mutation in patients with GH in Cantabria, Spain, seems to be lower than in North America and in North Europe patients.

Squamous cell carcinoma arising in a cutaneous epidermal cyst: case report and literature review

Although cutaneous epidermal (infundibular) cysts are extremely common lesions, neoplastic transformation of their epithelium is quite rare. We describe a patient with a squamous cell carcinoma arising in the wall of an otherwise conventional epidermal cyst. In addition, we review the literature concluding that most of the previously reported cases may not correspond to this rare occurrence.

Variation in resistance of natural isolates of Escherichia coli O157 to high hydrostatic pressure, mild heat, and other stresses

Strains of Escherichia coli O157 isolated from patients with clinical cases of food-borne illness and other sources exhibited wide differences in resistance to high hydrostatic pressure. The most pressure-resistant strains were also more resistant to mild heat than other strains. Strain C9490, a representative pressure-resistant strain, was also more resistant to acid, oxidative, and osmotic stresses than the pressure-sensitive strain NCTC 12079. Most of these differences in resistance were observed only in stationary-phase cells, the only exception being acid resistance, where differences were also apparent in the exponential phase. Membrane damage in pressure-treated cells was revealed by increased uptake of the fluorescent dyes ethidium bromide and propidium iodide. When strains were exposed to the same pressure for different lengths of time, the pressure-sensitive strains took up stain sooner than the more resistant strain, which suggested that the differences in resistance may be related to susceptibility to membrane damage. Our results emphasize the importance of including stress-resistant strains of E. coli O157 when the efficacy of a novel or mild food preservation treatment is tested.

Prevalence of intestinal parasite infections with special reference to Entamoeba histolytica on the island of Bioko (Equatorial Guinea)

The prevalence of intestinal parasitic infections was assessed (1993 through 1995) among two different groups of persons on the island of Bioko, Equatorial Guinea. In the first group, parasitologic examinations were performed on stool specimens from a household-based sample of 557 dwellers from the rural area of the island. In the second group, 1,633 inpatients and outpatients at the General Hospital of Malabo (the capital of the country) were studied. All age groups were represented in both groups. The average prevalence of the most common protozoan and helminthic intestinal infections in rural and urban areas, respectively, was as follows: Entamoeba histolytica/E. dispar (14.9% and 32.7%, respectively), Giardia lamblia (7.2% and 8.6%), Ascaris lumbricoides (45.8% and 31.4%), and Trichuris trichiura (25.7% and 36.4%). Seventy-nine sera from patients with amebic liver abscess (suspected by ultrasonography) were studied by an immunohemagglutination assay, with 44 (56%) showing anti-E. histolytica titers > or = 1:32. Of these 79 sera, 71 were studied by an enzyme immunoassay, 86% of which were positive with titers > or = 1:64. This study showed that parasitic infections in Equatorial Guinea represent a major health problem.

Semi-nested, multiplex polymerase chain reaction for detection of human malaria parasites and evidence of Plasmodium vivax infection in Equatorial Guinea

A semi-nested, multiplex polymerase chain reaction (PCR) based on the amplification of the sequences of the 18S small subunit ribosomal RNA (ssrRNA) gene was tested in a field trial in Equatorial Guinea (a hyperendemic focus of malaria in west central Africa). The method uses a primary PCR amplification reaction with a universal reverse primer and two forward primers specific for the genus Plasmodium and to mammals (the mammalian-specific primer was included as a positive control to distinguish uninfected cases from inhibition of the PCR). The second amplification is carried out with the same Plasmodium genus-specific forward primer and four specific reverse primers for each human Plasmodium species. The PCR amplified products are differentiated by fragment size after electrophoresis on a 2% agarose gel. Four villages from three regions of the island of Bioko (Equatorial Guinea) and two suspected Plasmodium vivax-P. ovale infections from the hospital of Malabo were tested by microscopy and PCR. The PCR method showed greater sensitivity and specificity than microscopic examination and confirmed the existence of a focus of P. vivax infections in Equatorial Guinea suspected by microscopic examination. It also provided evidence of several mixed infections, mainly P. falciparum and P. malariae, the two predominant species causing malaria in Equatorial Guinea.

The expression of recombinant genes from bacteriophage lambda strong promoters triggers the SOS response in Escherichia coli

The production of several non-related heterologous proteins in recombinant Escherichia coli cells promotes a significant transcription of recA and sfiA SOS DNA repair genes. The activation of the SOS system occurs when the expression of plasmid-encoded genes is directed by the strong lambda lytic promoters, but not by IPTG-controlled promoters either at 37 or at 42 degrees C, and it is linked to an extensive degradation of the proteins after their synthesis. The triggering signal for the SOS response could be an important arrest of cell DNA replication observed within the first hour after the induction of recombinant gene expression. The stimulation of this DNA repair system can partially account for the toxicity exhibited by recombinant proteins on actively producing E. coli cells.

Diagnosis of the CMT1A duplication by PCR based detection of a novel junction fragment

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Conformational flexibility in a highly mobile protein loop of foot-and-mouth disease virus: distinct structural requirements for integrin and antibody binding

The G-H loop of foot-and-mouth disease virus VP1 protein is a highly mobile peptide, that extends from the capsid surface and that in native virions is invisible by X-ray crystallography. In serotype C, this segment contains a hypervariable region with several continuous, overlapping, B-cell epitopes that embrace the conserved Arg-Gly-Asp (RGD) cell attachment motif. The solvent-exposed positioning of this peptide by selective insertion into different structural frameworks of E. coli beta-galactosidase, generates a spectrum of antigenic variants which react distinctively with a panel of anti-VP1 monoclonal antibodies and exhibit different efficiencies as cell ligands. The cell attachment efficiency is much less restricted by the different positioning of the viral segment at the insertion sites. A molecular model of an inserted stretch reveals a highest flexibility of the RGD tripeptide segment compared with the flanking sequences, that could allow a proper accommodation to integrin receptors even in poorly antigenic conformations. The non-converging structural requirements for RGD-mediated integrin binding and antibody recognition, explains the dynamism of the generation of neutralisation-resistant antigenic variants in the viral quasi-species, arising from a conformational space of integrin-binding competent peptides. This might be of special relevance for foot-and-moth disease virus evolution, since unlike in other picornaviruses, the cell binding motif and the major neutralising B-cell epitopes overlap in a solvent-exposed peptide accessible to the host immune system, in a virion lacking canyons and similar hiding structures.

A cell adhesion peptide from foot-and-mouth disease virus can direct cell targeted delivery of a functional enzyme

The G-H loop of foot-and-mouth disease virus is a disordered protrusion of the VP1 protein exposed on the virion surface. This short stretch includes an arginine-glycine-aspartic acid tripeptide, a recognized integrin-binding motif, which is responsible for cell attachment and infection. Eight copies of a peptide reproducing the amino acid sequence of this FMDV ligand have been displayed in solvent-exposed regions on an enzymatically active recombinant beta-galactosidase. This viral peptide segment enables the chimeric enzyme to bind mammalian cell lines with different efficiencies, probably depending on the number of suitable cell receptors present on each of them. Moreover, it also promotes the internalization of the attached enzyme, which is transiently active inside the cells. These results suggest further exploration of the potential use of short adhesion peptides of viral origin as cell attachment tags to direct the targeted delivery of both genes and enzymes, instead of whole, infectious viruses.

[Congenital chylothorax]

OBJECTIVE

The aim of this study was to study the prenatal diagnosis, clinical manifestations and karyotype results in congenital chylothorax.

PATIENTS AND METHODS

A retrospective survey of a 20 year period was carried out. The prenatal diagnosis, maneuvers following delivery, malformations and clinical outcome were studied.

RESULTS

We found 10 cases of congenital chylothorax. Four were diagnosed by prenatal ultrasound with pleural effusion and no other signs of hydrops and six were diagnosed postnatally. Of the later, five had respiratory distress and one was diagnosed by radiological procedures. In all 10 cases, postnatal thoracocentesis was performed for diagnosis and therapy, five infants required mechanical ventilation and four parenteral nutrition. One patient died 72 hours after birth and three within 24 hours of birth. The clinical outcome of the rest was successful and were placed on a medium-chain triglyceride formula that was given orally. Of the eight karyotypes studied, six trisomy 21 were found.

CONCLUSIONS

The prenatal diagnosis of pleural effusion permits prompt recognition of congenital chylothorax and allow for appropriate treatment upon birth. Medical therapy including pleural drainage and total parenteral nutrition and medium-chain triglyceride formula for oral feedings is successful in the majority of cases. Down's syndrome should be considered in fetuses or newborns with pleural effusion.

Analysis of engraftment kinetics in pediatric patients undergoing autologous PBPC transplantation

We sought to analyze factors that affect the engraftment kinetics following autotransplantation with PBPC mobilized by filgrastim (G-CSF). Forty-six consecutive pediatric patients with hematologic malignancies (n = 23) or solid tumors (n = 23) underwent autologous PBPC transplantation after myeloablative therapy. PBPC were mobilized using G-CSF alone. All patients received G-CSF after PBPC infusion. Factors potentially influencing the neutrophil and platelet engraftment were examined using univariate and multivariate analysis. All patients experienced rapid hematopoietic recovery, with a median of 9 days (range 7-15) to achieve a neutrophil count of 0.5 x 10(9)/L and a median of 15 days (range 9-37) to achieve a platelet count of 20 x 10(9)/L. The most important predictive factor of both platelet (p = 0.002) and neutrophil (p = 0.0001) recovery was the number of CD34+ cells infused. Patients receiving > or =5 x 10(6)/kg CD34+ cells had a more rapid hematopoietic recovery (p < 0.001) than those receiving a lower cell dose. The CD34+ cell dose is the most important predictive factor for engraftment kinetics after PBPC transplantation. Although a minimal CD34+ cell dose could not be defined, a dose > or =5 x 10(6)/kg CD34+ cells may be optimal to ensure rapid neutrophil and platelet recovery.

Display-induced antigenic variation in recombinant peptides

Peptide display on solvent-exposed surfaces of carrier proteins is a promising approach pursuing the identification and improvement of reactive amino acid sequences. However, the contribution of the molecular environment where the peptide is inserted on its interactive properties remains essentially unexplored. By an exhaustive antigenic analysis of the same peptide displayed on 20 structurally distinct frameworks, we show that peptide accommodation into the acceptor site has dramatic effects on its immunoreactivity. Conformational constraints can modulate the molecular recognition properties of the insert within a surprisingly wide range, probably by affecting the positioning of critical contact residues. The observed display-induced antigenic variation prompts a careful consideration of the molecular context when evaluating output amino acid sequences from screening of peptide libraries or application of directed molecular evolution technologies.

Magnetic resonance imaging in a patient with a dual-chamber pacemaker

The presence of an implanted cardiac pacemaker has been considered an absolute contraindication for magnetic resonance imaging due to the interactions between the pulse generators and the magnetic and radiofrequency fields generated by the magnetic resonance unit. We describe the case of a patient with a dual-chamber pacemaker who underwent two magnetic resonance imaging examinations of the head without any sequelae. Both procedures were performed with a 1 Tesla unit, with the pacemaker programmed to the AOO mode. The only interference observed was activation of the reed switch -probably due to the static magnetic field- resulting in asynchronous atrial pacing at the magnet rate. Although the general policy of never exposing a patient with a pacemaker to magnetic resonance imaging should not be revised, we think that if the testing is considered essential, it could be safely used in certain carefully selected patients.

Biosensor characterization of antigenic site A of foot-and-mouth disease virus presented in different vector systems

The region 141-160 of the VP1 protein of foot-and-mouth disease virus known as site A is an immunodominant region that has been extensively studied for the purpose of developing a synthetic vaccine. In the present study, site A of foot-and-mouth disease virus was inserted in three different loops of the maltose-binding protein and its antigenicity was compared with site A presented as a conjugated synthetic peptide or inserted in beta-galactosidase. The affinity of antibodies elicited against the site A synthetic peptide was also compared with that of antibodies raised against the site A inserted within the two carrier proteins. Using biosensor technology it was possible to estimate the concentration of site A antibodies present in the various antisera and to show that site A fused to maltose-binding protein was a slightly better mimic of the epitope present in the virus particle than the synthetic peptide or the beta-galactosidase recombinant construct.

Megatherapy in children with high-risk Ewing's sarcoma in first complete remission

To improve the prognosis of patients with metastatic or high-risk localized sarcoma in first CR, we explored the role of consolidation therapy with megatherapy and hematopoietic rescue. From 1986 to 1995, of 72 patients with Ewing's sarcoma from three pediatric departments, 30 were diagnosed as high-risk patients. Of these 30 patients, six did not achieve complete remission and four refused megatherapy and received multimodal treatment (chemotherapy + surgery and/or radiotherapy). The remaining 20 patients received megatherapy. There were 15 males and five females with a median age of 10.8 years (range 2-18 years). Five patients had metastatic disease at initial diagnosis, nine patients had primary tumor in the pelvis and 13 had a tumor volume greater than 100 ml. Overall disease-free survival was 62.7+/-11%; 40+/-21.9% for those with metastatic disease, 76.2+/-12.2% for those with tumor volume greater than 100 ml and 64.8+/-16.5% for those with tumor in pelvic bones. In conclusion, megatherapy has improved the outcome of this group of patients relative to that expected following conventional therapy.

Progenitor cell subsets and engraftment kinetics in children undergoing autologous peripheral blood stem cell transplantation

The main objective of the present study was to determine the role of CD34+ cell subsets in the haemopoietic recovery of children undergoing peripheral blood stem cell transplantation. For this purpose, 38 leukaphereses from 33 children with malignancies mobilized with G-CSF were analysed. Using dual-colour flow cytometry, different subpopulations of CD34+ cells were quantified and the number of each reinfused subsets correlated with haemopoietic resurgence. Multivariate analysis showed that the number of CD34+CD38- cells and CD34+CD38+ cells correlated better with time to neutrophil and platelet recovery, respectively, than the total number of CD34+ cells. Threshold values for rapid haemopoietic recovery, determined by the receiver operating characteristic analysis, were found to be 0.5 X 10(6) CD34+CD38- cells for neutrophil engraftment, and 2.0x10(6) CD34+CD38+ cells for platelet recovery. It is suggested that the analysis of CD34+ cell subsets could increase understanding of the repopulation capacity of a given leukapheresis product in peripheral blood stem cell transplantation procedures in children. In particular, this procedure could be extremely useful when low numbers of CD34+ cells are collected.

Peripheral blood progenitor cells for autologous transplant in children

Autologous peripheral blood progenitor cell transplantation has become an accepted procedure to support high dose chemotherapy in adults and children with cancer. The use of hematopoietic growth factors alone for mobilization of PBSC avoids the potential side effects of myelotoxic regimens and is as effective in reconstituting hematopoiesis as other mobilization methods. Many problems associated with apheresis procedures arise when PBPCs are harvested in small children. Large-volume-leukapheresis using a continuous flow blood cell separator allows us the collection of peripheral blood stem cells in children, even in the small ones. The speed of hematological recovery highly correlates with the number of CD34+ infused cells. We consider that a CD34+ cell dose of 5.0 x 10(6)/kg may be sufficient to ensure a rapid neutrophil and platelet recovery in pediatric patients mobilized by G-CSF.

Salivary gland heterotopia in the lower neck: a report of five cases

Heterotopic salivary gland tissue (HSGT) represents an uncommon lesion, usually presenting as a discharging sinus in the base of the neck. Diagnostic criteria and embryogenesis of this entity still remain unclear. For the purpose of clarifying both subjects, all lateral cervical anomalies undergoing surgery during a 12-year period were examined. Histological study showed salivary tissue in 10 out of 119 patients. However, only 5 of them accomplished HSGT criteria. This study presents the second largest series to date of undisputed HSGT in the lower neck. Both accessory glands and branchial cleft anomalies should be distinguished from this lesion. Neoplastic transformation in HSGT, although extremely rare, should also be considered.

Expression of Bcl-x in erythroid precursors from patients with polycythemia vera

BACKGROUND

Deregulating the expression of Bcl-xL, an inhibitor of apoptosis, in an erythropoietin-dependent erythroblast cell line averts apoptosis induced by the withdrawal of erythropoietin. Since in polycythemia vera an abnormal clone of erythroid progenitors is independent of erythropoietin, we investigated whether the endogenous expression of Bcl-xL was deregulated in these cells.

METHODS

Erythroid colonies from patients with polycythemia vera and normal subjects were cultured in the presence and absence of erythropoietin and assessed by immunocytochemical and flow-cytometric analysis with anti-Bcl-x antibodies that recognize the two species of Bcl-x (Bcl-xL and Bcl-xS). Reverse-transcriptase-polymerase-chain-reaction analysis was used to determine which one of the two species was responsible for anti-Bcl-x staining. Bone marrow mononuclear cells from 8 healthy bone marrow donors, 14 patients with polycythemia vera, 19 patients with other myeloproliferative syndromes, and 12 patients with secondary erythrocytosis were analyzed by flow cytometry with antibodies against Bcl-x and glycophorin A, an erythroid marker.

RESULTS

Erythroid cells from patients with polycythemia vera survived in vitro without erythropoietin, and this finding correlated with the expression of Bcl-x protein (Bcl-xL messenger RNA was the main species of Bcl-x found), even in mature erythroblasts that normally do not express Bcl-x. The mean (+/-SD) percentage of cells positive for both glycophorin A and Bcl-x in the 14 patients with polycythemia vera (21.8+/-3.6 percent) was significantly higher than that in 8 normal donors (6.62+/-1.58 percent), 12 patients with secondary erythrocytosis (6.87+/-1.95 percent), 9 patients with essential thrombocythemia (3.81+/-0.97 percent), and 10 patients with chronic myeloid leukemia (2.7+/-0.41 percent).

CONCLUSIONS

Deregulated expression of Bcl-x may contribute to the erythropoietin-independent survival of erythroid-lineage cells in polycythemia vera and thereby contribute to the pathogenesis of this disease.

Peripheral blood progenitor cell collection by large-volume leukapheresis in low-weight children

Large-volume leukapheresis (LVL), defined as the processing of at least three blood volumes in a single session for peripheral blood progenitor cell (PBPC) collection, was performed in 32 small children weighing < or = 25 kg, aged 10 months to 8 years, with a variety of malignancies. Harvesting of PBPC was started after 4 days of cytokine (G-CSF, 12 micrograms/kg s.c.) alone. Procedures were performed using a continuous flow blood cell separator (COBE Spectra). The automated program of lymphocytapheresis was modified to achieve a collection rate of 0.9 ml/min. The extracorporeal line was primed with a unit of a packed red blood cells before the procedure. Acid citrate dextrose (ACD) was used as anticoagulant with an ACD inlet ratio of 1:14 and an ACD infusion rate of 1.1 ml/min/L of total blood volume. The inlet flow ranged between 6 and 35 ml/min (median 20 ml/min). A total of 37 apheresis procedures were performed (median 1, range 1-3). In 84% of patients, a single apheresis yields the minimum number of PBPC cells required for transplantation. No consistent side effects were observed, and LVL was well tolerated by children. A median of 7.7 x 10(8) kg MNC, 5.4 x 10(6)/kg CD34+, and 6.2 x 10(4)/kg CFU-GM per apheresis were harvested. Patients with neuroblastoma had a significantly lower yield than other patients. To date, 27 patients have been transplanted after myeloablative treatment, and rapid and sustained engraftment was achieved in all cases. The number of CD34+ cells infused was highly correlated with engraftment kinetics. LVL can be safely and easily performed in small children, allowing adequate PBPC collection for transplantation with rapid hematologic recovery.

Pathogenesis of polycythemia vera

BACKGROUND AND OBJECTIVE

Polycythemia vera (PV) is an acquired clonal myeloproliferative disorder characterized by increased production of mature red cells. We still lack a molecular target responsible for this disorder; however, recent investigations have focused on a number of molecules involved in signal transduction pathways mediated by erythropoietin (Epo) and other growth factors. Here we review the implication of these molecules in the pathogenesis of PV.

INFORMATION SOURCES

The material reviewed in this work includes articles published in journals covered by Medline. We also include data obtained in our laboratory regarding to the significance of apoptosis inhibitory proteins in erythroid development.

STATE OF THE ART AND PERSPECTIVES

Overproduction of erythroid cells in PV is particular in that it occurs in the absence of a recognizable physiologic stimulus, since circulating serum levels of Epo are normal or lower than normal. Genetic analysis as well as in vitro studies, have established an essential role for Epo in the survival and maturation of committed erythroid progenitors. Epo initiates its cellular response by binding to the Epo receptor (EpoR) expressed on the surface of immature erythroblasts. Following ligand binding, EpoR is known to activate a cytoplasmic protein tyrosine kinase, Jak2 which triggers a signal transduction cascade that leads to the development of early erythroid progenitors into mature erythroblast cells. Although the mechanism underlying the increased erythroid production in PV is not well understood, a number of causes have recently came for which may provide insights not only for the pathogenesis of PV but also for a fundamental biological process: the mechanism whereby a multipotential stem cell gives rise to a particular cell lineage.

CNS sequelae in Langerhans cell histiocytosis: progressive spinocerebellar degeneration as a late manifestation of the disease

Central nervous system involvement in Langerhans cell histiocytosis (LCH), formerly known as histiocytosis X, is manifested mainly by diabetes insipidus reflecting local infiltration of Langerhans cells into the posterior pituitary or hypothalamus. We describe two patients with progressive spinocerebellar degeneration appearing 4 and 6 years after the initial diagnosis of LCH. No correlation was found between the clinical course of the disease or its treatment and the neurological impairment. An extensive search for metabolic, toxic, neoplastic, and hereditary etiologies for progressive cerebellar degeneration was negative.

Apoptosis of human myeloid leukemia cells induced by an inhibitor of protein phosphatases (okadaic acid) is prevented by Bcl-2 and Bcl-X(L)

Okadaic acid, an inhibitor of serine/threonine protein phosphatases 1 and 2A has been shown to cause mitotic arrest and cell death of HL-60 and K562 cells. HL-60 cells express Bcl-2 and little or no Bcl-X(L), while K562 expresses Bcl-X(L) but not Bcl-2. Since phosphorylation/dephosphorylation reactions have been suggested to be involved in the regulation of Bcl-2, we planned to investigate whether the expression of Bcl-2, Bcl-X(L) and Bax, a protein that antagonizes the antiapoptotic function of Bcl-2, are regulated in myeloid leukemia cell lines (K562, KU812 and HL-60) treated with okadaic acid. Our results indicate that exposure of all three leukemic cell lines to nanomolar concentrations of okadaic acid causes a loss of viability by activation of an apoptotic process accompanied by a marked decrease in the expression of Bcl-2, Bcl-X(L) and Bax at both mRNA and protein level, but not of c-fos, vimentin and epsilon-globin, ruling out a non-specific effect of okadaic acid. Furthermore, constitutive expression of either Bcl-X(L) or Bcl-2 by gene transfer inhibited apoptosis triggered by okadaic acid in K562 cells. Thus, we suggest that protein phosphatases may be involved in maintaining the expression of bcl-2 family genes as part of the survival machinery of the cell.

Non-tunneled catheters for the collection and transplantation of peripheral blood stem cells in children

We analyzed the use of non-tunneled (polyurethane, double lumen) central venous catheters (CVCs) for the collection, conditioning, transplantation and immediate post-transplantation periods in 56 children with various malignant diseases. A total of 71 leukaphereses were performed, with a mean of 1.2 apheresis per patient, following administration of granulocyte colony-stimulating factor (G-CSF) using a continuous flow blood cell separator (Cobe Spectra). The mean TBV (total blood volume) processed was 4.5 +/- 1.2 s.d. (range 2.4-7). The mean flow rate was 30.6 ml/min and the duration of a single apheresis was 327 +/- 84 s.d. (range 175-511 min). The mean purities and efficacies of collections were 77.38 +/- s.d. (range 42-100) and 42.78 +/- s.d. (range 24-80), respectively. The mean numbers of mononuclear cells (MNC) and CD34+ cells collected were 9.3 +/- 6.9 s.d. x 10(8)/kg (range 2-49) and 6.2 +/- 7.2 s.d. x 10(6)/kg (range 1-42), respectively. We observed the following complications during catheter insertion for collection: pneumothorax (1.7%), mechanical dysfunction (3.5%) that resolved with thrombolytic therapy. Complications during conditioning, transplantation and immediate post-transplantation periods were entry site infection in five patients (8.92%), catheter-related infection in two (3.57%) and catheter-related sepsis in three (5.35%). Our results indicate that the collection of PBSC with non-tunneled catheters is safe, effective and dis associated with a low incidence of complications.

The expression of Bcl-x is downregulated during differentiation of human hematopoietic progenitor cells along the granulocyte but not the monocyte/macrophage lineage

Expression of the apoptosis inhibitory protein Bcl-x was studied in CD34+ hematopoietic precursor cells and in the promyelocytic leukemia cell line HL-60. The enriched population of CD34+ cells (more than 95%) was cultured in the presence of stem cell factor, interleukin-3 (IL-3), IL-6, and either granulocyte colony-stimulating factor or macrophage colony-stimulating factor to achieve granulocyte or monocyte/macrophage differentiation, respectively. The expression of Bcl-x increased in the early stages of both differentiation pathways. However, by day 21 of culture mature granulocytes were Bcl-x-negative, whereas monocytes/macrophages either maintained or increased the expression of Bcl-x. The pattern of Bcl-x expression in the differentiated CD34+ cells was similar to that observed in HL-60 cells differentiated along the granulocyte lineage (induced by incubation with retinoic acid), or along the monocyte/macrophage lineage (induced by incubation with phorbol diester). The bcl-x transcript predominant in HL-60 and CD34+ cells differentiated into monocytes/macrophages was bcl-xL. Although little is yet known regarding the functional significance of Bcl-x within the granulomonocytic compartment, marked changes in the pattern of its expression, as observed during granulomonocytic differentiation of HL-60 and CD34+ cells, are likely to alter the life span of mature granulocytes and monocytes/macrophages.

Selective induction of apoptosis in cancer cells by the ether lipid ET-18-OCH3 (Edelfosine): molecular structure requirements, cellular uptake, and protection by Bcl-2 and Bcl-X(L)

The ether lipid 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3; Edelfosine) has been shown to be a rapid inducer of apoptosis in human leukemic cells and has been considered as a promising drug in cancer treatment. Here we have found that ET-18-OCH3 induced apoptosis not only in human tumor cell lines but also in primary tumor cell cultures from cancer patients. Human leukemic cells were highly sensitive to ET-18-OCH3, whereas normal cells remained unaffected. Among the distinct modifications of the ET-18-OCH3 molecule assayed, we found that substitutions in positions sn-2 and sn-3 of the glycerol backbone resulted in a complete loss of its capacity to induce apoptosis, highlighting the importance of the molecular structure of ET-18-OCH3 in its apoptotic effect. Induction of apoptosis by ET-18-OCH3 was very well correlated with the uptake of this ether lipid. ET-18-OCH3-resistant 3T3 fibroblasts became sensitive and incorporated significant amounts of the ether lipid following transformation with the SV40 virus. ET-18-OCH3-induced apoptosis as well as ET-18-OCH3 uptake were not mediated through binding of the ether lipid to the platelet-activating factor receptor. Overexpression of bcl-2 or bcl-xL by gene transfer in the human erythroleukemic HEL cells abrogated apoptosis induced by ET-18-OCH3. ET-18-OCH3 did not affect the expression of bcl-2, bcl-xL, or bax in HEL and HL-60 human leukemic cells but induced expression of c-myc, an important effector of apoptosis in several systems. Thus, ET-18-OCH3 behaves as a potent and highly selective antitumor drug able to induce an apoptotic pathway of cell death in tumor cells but not in nonmalignant cells.

Interventional therapeutic techniques in Budd-Chiari syndrome

PURPOSE

To analyze the results obtained with percutaneous therapeutic procedures in patients with Budd-Chiari syndrome (BCHS).

METHODS

Between August 1991 and April 1993, seven patients with BCHS were treated in our hospital. Three presented with a congenital web; in another three cases the hepatic veins and/or the inferior vena cava (IVC) were compromised after major hepatic surgery; one patient presented with a severe stenosis of the intrahepatic IVC due to hepatomegaly.

RESULTS

One of the patients with congenital web has required several new dilatations due to restenosis; one patient required a transjugular intrahepatic portosystemic shunt procedure while awaiting a liver transplantation. The two postsurgical patients with stenosed hepatic veins did not require any new procedure after the placement of metallic endoprostheses. However, the patient with liver transplantation presented IVC restenosis after balloon angioplasty that required the deployment of metallic endoprostheses. In the patient with hepatomegaly a self-expandable prosthesis was placed in the intrahepatic portion of the IVC before (4 months) a liver transplantation.

CONCLUSION

Interventional therapeutic techniques offer a wide variety of possibilities for the treatment of patients with BCHS. For IVC stenoses, the results obtained with balloon angioplasty are at least as good as those obtained with surgery.