Patterns of hematopoietic lineage involvement in children with neurofibromatosis type 1 and malignant myeloid disorders

Children with neurofibromatosis type 1 (NF1) are at increased risk of developing malignant myeloid disorders, particularly juvenile chronic myelogenous leukemia/juvenile myelomonocytic leukemia (JCML/JMML). We investigated bone marrows from 11 such patients (8 boys and 3 girls) and detected allelic losses at the NF1 locus in 4 of them and probable losses in 2 others. To determine which hematopoietic cell lineages were derived from the abnormal clones, Epstein-Barr virus (EBV)-transformed cell lines and CD34+ cells were analyzed from 3 children with JCML with allelic losses in unfractionated marrow. CD34 cells from these 3 patients lacked the normal NF1 allele, whereas EBV cell lines retained it. Erythroblasts plucked from the burst-forming unit-erythroid colonies of one of these children lacked the normal NF1 allele. We also studied a 10-month-old boy with NF1 who developed an unusual myeloproliferative syndrome. His bone marrow and EBV cell line both showed loss of the normal NF1 allele. In our series and in the literature, male sex and maternal transmission of NF1 were associated with the highest risk of myeloid leukemia. These data (1) provide strong genetic evidence that NF1 functions as a tumor-suppressor in early myelopoiesis, (2) confirm the clonal nature of JCML/JMML, (3) suggest that the elevation in fetal hemoglobin seen in JCML/JMML is a result of primary involvement of erythroid progenitors in the malignant clone, (4) show consistent loss of NF1 in the CD34 cells of affected children and show that the malignant clone may also give rise to pre-B cells in some cases, and (5) implicate epigenetic factors in the development of leukemia in children with NF1.     

Prolonged administration of granulocyte colony-stimulating factor (filgrastim) to patients with Fanconi anemia: a pilot study

This report examines the effect of filgrastim (granulocyte colony- stimulating factor, [G-CSF] in 12 patients with neutropenia [absolute neutrophil count [ANC] < 1,000/mm3]) caused by Fanconi anemia (FA). Two of 14 patients who were evaluated for study entry were ineligible because of unsuspected cytogenetic abnormalities in their bone marrow (BM). G-CSF was started at 5 micrograms/kg/d. All patients had an increase in their ANC at week 8 (mean increase = 15,664/mm3). The median ANC during therapy was 5,030/mm3. Eight of 10 patients who completed 40 weeks on study maintained an ANC > 1,500/mm3 on G-CSF given every-otherday. Four patients had an increase in their platelet count by week 8 without transfusion (maximum increase = 23,000 to 45,000/mm3); however, platelet counts fell toward baseline levels as the G-CSF dose was reduced. BM CFU-MK were increased at week 8 in three of four evaluable patients. Four patients who did not receive red blood cell transfusions had an increase in their hemoglobin level of at least 2.0 g/dL. A fifth patient had a red blood cell transfusion in week 2 and then had a similar increase in hemoglobin level without subsequent transfusion. Eight of 10 patients who completed 40 weeks of treatment showed increases in the percentage of BM CD34+ cells measured by flow cytometry. The same proportion showed increases in peripheral blood CD34+ cells. Increased BM cellularity and myeloid hyperplasia were constant findings and were associated with increased expression of the proliferating cell nuclear antigen. Adverse experiences were mild fever (1 patient) and a new BM cytogenetic abnormality at week 40 (1 patient). This study shows that prolonged administration of G-CSF exerts a stimulatory effect on the BM of FA patients and may be used to maintain a clinically adequate ANC in these patients. G-CSF has beneficial effects on multiple hematopoietic lineages in some patients and may be a good candidate for use in combination cytokine protocols for FA patients with progressive aplastic anemia. G-CSF use results in an increase in circulating CD34+ cells, a finding with important implications for future gene transfer protocols.     

Polymorphonuclear neutrophils from human immunodeficiency virus- infected patients show enhanced activation, diminished fMLP-induced L- selectin shedding, and an impaired oxidative burst after cytokine priming

Impaired polymorphonuclear neutrophil (PMN) function may contribute to the onset of certain life-threatening bacterial and fungal infections in human immunodeficiency virus (HIV)-infected patients. Published data on PMN functional activity in HIV infection are controversial, possibly because most studies have involved PMNs isolated from their blood environment by means of various procedures that may differently affect surface receptor expression and thereby alter cellular responses. We therefore used flow cytometry to study the expression of adhesion molecules at the PMN surface, actin polymerization, and the oxidative burst of whole-blood polymorphonuclear neutrophils in 42 HIV-infected patients at different stages of the disease. These PMNs were activated in vivo, as demonstrated by increased expression of the adhesion molecule CD11b/CD18, reduced L-selectin antigen expression, increased actin polymerization, and increased H2O2 production. The alterations were present in asymptomatic patients with CD4+ cell counts greater than 500/microL and did not increase with the progression of the disease. Stimulation by bacterial N-formyl peptides showed dysregulation of L-selectin shedding and decreased H2O2 production after ex vivo priming with tumor necrosis factor alpha or interleukin-8 (IL-8). These latter impairments, which correlated with the decrease in CD4+ lymphocyte numbers and with IL-8 and IL-6 plasma levels, could contribute to the increased susceptibility of HIV-infected patients to bacterial infections.     

Loss of attachment to fibronectin with terminal human erythroid differentiation

Human erythroblastic progenitors (colony-forming unit-erythroid [CFU-E] and burst-forming unit-erythroid [BFU-E]) have been shown to attach to fibronectin (Fn), a property that might be involved in the local regulation of erythropoiesis. In this study, we have investigated changes in cell attachment to Fn upon terminal erythroid differentiation. We first purified CFU-E from human marrow by avidin- biotin immune rosetting. This negative selection procedure yielded a cell population containing approximately 80% blasts that, after characterization by colony-assays and electron microscopy, appeared to consist of CFU-E (10% to 15%) and their immediate progeny (85% to 90%), here defined as "preproerythroblasts." In the presence of erythropoietin, purified cells differentiated into reticulocytes in 7 to 10 days. Cell attachment to Fn was inversely correlated to the stage of differentiation of the erythroid cell: more than 50% of the CFU-E population reproducibly adhered to Fn, whereas at most 30% of the preproerythroblasts had the same capacity. Adhesion was further lost at late maturation stages, and a constant finding was the inability of reticulocytes to adhere to Fn. Finally, CFU-E adhesion to Fn was blocked by polyclonal lgG raised against the Fn receptor and by a monoclonal antibody against VLA-5. These results demonstrate that adhesion to Fn is developmentally regulated during normal human erythropoiesis. Restriction of its expression to CFU-E and its first divisions strikingly correlates with the migratory capacity of these cells.     

Arginyl-glycyl-aspartic acid sequences and fibrinogen binding to platelets

Human fibrinogen has an Arg-Gly-Asp-Ser (RGDS) sequence at residues 572- 575 of its A alpha-chain. Although RGDS-containing peptides inhibit fibrinogen binding to stimulated platelets, these peptides also inhibit platelet binding of human fibrinogen fragment X and rat fibrinogen, which lack RGDS sequences corresponding to A alpha 572-575. Thus competition between free RGD-containing peptides and internal RGDS sequence at A alpha 572-575 is not the basis for their inhibition of fibrinogen binding to platelets. Addition of a Thr to the carboxy- terminus and an Asn to the amino-terminus of the RGDS sequence, the amino acids corresponding to A alpha 576 and 571 respectively, reduced the inhibitory potency of RGDS-containing peptides by fourfold to tenfold. Arg-Gly-Asp-Phe (RGDF) corresponds to A alpha 95-98, and the RGDF peptide was an effective inhibitor of fibrinogen binding, fourfold to fivefold more potent than RGDS. Thus, local primary structure may play an important role in regulating the capacity of RGD sequences in proteins to interact with specific adhesion receptors.     

Androgen receptor: structure,role in prostate cancer and drug discovery

Androgens and androgen receptors (AR) play a pivotal role in expression of the male phenotype. Several diseases, such as androgen insensitivity syndrome (AIS) and prostate cancer, are associated with alterations in AR functions. Indeed, androgen blockade by drugs that prevent the production of androgens and/or block the action of the AR inhibits prostate cancer growth. However, resistance to these drugs often occurs after 2–3 years as the patients develop castration-resistant prostate cancer (CRPC). In CRPC, a functional AR remains a key regulator. Early studies focused on the functional domains of the AR and its crucial role in the pathology. The elucidation of the structures of the AR DNA binding domain (DBD) and ligand binding domain (LBD) provides a new framework for understanding the functions of this receptor and leads to the development of rational drug design for the treatment of prostate cancer. An overview of androgen receptor structure and activity, its actions in prostate cancer, and how structural information and high-throughput screening have been or can be used for drug discovery are provided herein.     

Nurses' attitudes towards the use of PRN psychotropic medications in acute and forensic mental health settings

Many countries now have national mental health policies and guidelines to decrease or eliminate the use of seclusion and restraint yet the use of Pro Re Nata (PRN) medications has received less practice evaluation. This research aimed to identify mental health nurses' attitudes towards the use of PRN medications with mental health consumers. Participants were working in forensic mental health and non‐forensic acute mental health settings. The “Attitudes towards PRN medication use survey” was used and data were collected online. Data were analysed using the Statistical Package Social Sciences, Version 22.0. Practice differences between forensic and other acute mental health settings were identified related to the use of PRN medications to manage symptoms from nicotine, alcohol and other drug withdrawal. Differences related to the useage of comfort rooms and conducting comprehensive assessments of consumers' psychiatric symptoms were also detected. Qualitative findings highlighted the need for increased accountability for the prescribing and administration of PRN medications along with more nursing education/training to use alternative first line interventions. Nurses administering PRN medications should be vigilant regarding the indications for this practice to ensure they are facilitating the consumer's recovery by reducing the use of all forms of potentially restrictive practices in the hospital setting. The reasons for using PRN medications and PRN administration rates must be continually monitored to avoid practices such as high dose antipsychotics use and antipsychotic polypharmacy to ensure the efficacy of the consumers' management plans on their health care outcomes.     

B-1a Lymphocytes Attenuate Insulin Resistance

Obesity-associated insulin resistance, a common precursor of type 2 diabetes, is characterized by chronic inflammation of tissues, including visceral adipose tissue (VAT). Here we show that B-1a cells, a subpopulation of B lymphocytes, are novel and important regulators of this process. B-1a cells are reduced in frequency in obese high-fat diet (HFD)-fed mice, and EGFP interleukin-10 (IL-10) reporter mice show marked reductions in anti-inflammatory IL-10 production by B cells in vivo during obesity. In VAT, B-1a cells are the dominant producers of B cell–derived IL-10, contributing nearly half of the expressed IL-10 in vivo. Adoptive transfer of B-1a cells into HFD-fed B cell–deficient mice rapidly improves insulin resistance and glucose tolerance through IL-10 and polyclonal IgM-dependent mechanisms, whereas transfer of B-2 cells worsens metabolic disease. Genetic knockdown of B cell–activating factor (BAFF) in HFD-fed mice or treatment with a B-2 cell–depleting, B-1a cell–sparing anti-BAFF antibody attenuates insulin resistance. These findings establish B-1a cells as a new class of immune regulators that maintain metabolic homeostasis and suggest manipulation of these cells as a potential therapy for insulin resistance.     

A case of gossypiboma mimicking intrahepatic cholangiocarcinoma

Introduction

A gossypiboma refers to a cotton-based foreign body left inadvertently in the human body following a surgical procedure. Although a rare event, they tend to be found in the abdomen but few are known to be intrahepatic.

Case history

We report the case of a 44 year-old man who presented with recurrent episodes of jaundice and cholangitis, on a background of a right hepatectomy for hydatid cyst excision 20 years previously. This case was discussed at our hepatobiliary multidisciplinary team meetings on several occasions and a presumed diagnosis of intrahepatic cholangiocarcinoma was made. Biopsies of the mass had purely shown inflammation and remained inconclusive. It was decided that the patient should undergo a complete extended right hepatectomy with resection and reconstruction of the left branch of the portal vein. On attempting to obtain intraoperative frozen section specimens prior to resection, open excision revealed two large swabs encased in a calcified cavity. Removal of the swabs resulted in resolution of the mass and obstructive symptoms.

Conclusions

Gossypiboma should be a rare differential diagnosis in all patients following a laparotomy presenting with obstructive symptoms, particularly in countries where strict surgical protocols may not be in place. This case also highlights the need to perform an intraoperative biopsy in any uncertain case of a liver lesion as we have shown that an extensive operation with its increased morbidity can occasionally be avoided.     

Refined mapping of genomic rearrangements involving the short arm of chromosome 9 in acute lymphoblastic leukemias and other hematologic malignancies

Deletions of chromosomal band 9p21 have been detected in various tumor types as well as in more than 20% of acute lymphoblastic leukemia (ALL). These deletions frequently include the entire interferon (IFN) gene cluster as well as the methylthioadenosine phosphorylase (MTAP) gene. Recently, the CDKN2 gene (p16INK4A, MTS I, CDK41) was proposed as a candidate tumor-suppressor gene on 9p21 because it is frequently deleted in cell lines derived from multiple tumor types. To determine if CDKN2 or another closely related gene on 9p is the target of 9p deletions in ALL and other hematologic malignancies, we analyzed 20 primary patient samples (13 ALL, 2 acute myeloid leukemias [AML], and 5 non-Hodgkin's lymphomas [NHL]) with 9p rearrangements using Southern blot analysis, fluorescence in situ hybridization (FISH), and single- strand conformation polymorphism (SSCP) for alterations of CDKN2. Homozygous deletions of the CDKN2/CDKN2B (p15) region were detected in 10 cases (50%; 6 ALL, 2 AML, and 2 NHL). In 1 additional case, the intensity of the Southern blot band was significantly reduced, suggesting a CDKN2 deletion in a subpopulation of the malignant cells. No CDKN2 or CDKN2B rearrangements were seen. The IFN gene cluster was homozygously deleted in 2 of 15 (13%) analyzed cases, whereas the MTAP gene was deleted in 6 of 15 cases (40%). In addition, hemizygous deletions of the CDKN2 region were identified in 6 ALL cases using interphase FISH. No point mutation of the coding region of CDKN2 was detected by SSCP in these cases. We conclude that CDKN2 is the most frequently homozygously deleted marker on 9p. The absence of point mutations in the coding region of CDKN2 in cases with hemizygous 9p deletions and the frequent codeletion of MTAP, CDKN2B, and other yet unidentified neighboring genes suggest that the simultaneous deletion of these genes may be necessary for the selective growth advantage of malignant cells.