Primary non-Hodgkin malignant lymphoma (NHML) of the CNS. A case of radiological and clinical remission

A case of primary non-Hodgkin malignant lymphoma (NHML) of the brain is described. Clinical, laboratory and radiological features before and after intrathecal chemotherapy and radiotherapy are reported and discussed.

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Sommario In questo lavoro è descritto un caso di linfoma maligno non-Hodgkin primitivo del Sistema Nervoso Centrale. Sono riportati e discussi gli aspetti clinici e radiologici prima e dopo il trattamento radioterapico e chemioterapico intratecale.

     

Obstructive sleep apnea in Costello syndrome

Costello syndrome (CS) was initially described by Costello in 1971; it is caused by a germline mutation in HRAS proto-oncogene. The aim of the present study was to evaluate the respiratory activity during sleep in a group of subjects with CS. We studied 10 consecutive patients, 4 males and 6 females, aged 3-29 years, affected by CS. All patients underwent clinical, neurological, otholaryngologic and radiologic evaluation, and a full-night polysomnography in the sleep laboratory. Polysomnography showed that seven patients presented a relevant number of respiratory events of obstructive type during sleep. The apnea-hypopnea index (AHI) ranged from 0 to 19.2 events per hour (mean index = 7.5 +/- 6.9 events/hr). In one patient AHI was not evaluable because of tracheostomy. Apnea induced mild or moderate hemoglobin desaturations (mean of lowest SpO2 values = 85.4 +/- 5.5%). Only sporadic respiratory pauses of central type were observed (mean number of central apnea per study: 7.2 +/- 6.8 events/hr). Sleep structure was fragmented, with a high number of awakenings (mean number of awakenings was 13.2 +/- 8.1; of these, 4.8 +/- 2.5 lasted longer than 2 min). In all patients, otolaryngologic and radiologic observations revealed one or more sites of narrowing in the upper airways. Our results suggest that Costello patients have a high prevalence of obstructive sleep-related respiratory disorders, which need to be assessed by means of polysomnography.     

Importance of catalase in the disposal of hydrogen peroxide within human erythrocytes

The catalase within normal, intact human erythrocytes was completely inactivated with amino triazole. The rate of 14CO2 evolution, when the cells were subsequently incubated with 14C-labeled glucose, provided a measure of the rate at which NADPH was being oxidized by the glutathione peroxidase/reductase system for the disposal of H2O2. This rate was determined in control cells and in catalase-inactivated cells while the cells were exposed to H2O2, which was generated at various constant and predetermined rates by glucose oxidase. The results indicated that catalase handles approximately half of the generated H2O2. The glutathione peroxidase/reductase mechanism accounted for the other half. These results are in agreement with our earlier findings on erythrocytes of a subject with a genetic deficiency of catalase. However, an unexpected result with the present approach was the finding that the increased dependence on the glutathione peroxidase/reductase mechanism did not occur until greater than 98% of the catalase had been inactivated. The latter observation indicates that catalase and the glutathione peroxidase/reductase system function intracellularly in a manner very different from that previously ascribed to them. An explanation of the findings requires that the two methods of H2O2 disposal function in a coordinated way, such as a sequential action in which the glutathione peroxidase/reductase system is the rate-limiting step.     

Increased expression of the G gamma and A gamma globin genes associated with a mutation in the A gamma enhancer

We have previously described a unique type of delta beta-thalassemia in a Chinese family characterized by increased expression of the G gamma and A gamma fetal globin genes in the absence of a large deletion in the beta-globlin gene cluster. Our earlier study of the beta-globin gene on this delta beta-thalassemia chromosome showed a promoter mutation in the TATA box. In this report, we describe the results of our study of the fetal globin domain of this delta beta-thalassemia chromosome. We have cloned a 13-kb DNA fragment that includes the G gamma and the A gamma genes and the 3' A gamma enhancer element of this delta beta-thalassemia chromosome. DNA sequence analysis of the G gamma and A gamma-globin genes including their promoters did not show any mutations, but analysis of the putative enhancer element downstream from the A gamma-globin gene showed a C to T substitution 2,401 nucleotides downstream from the A gamma cap site. We performed DNA linkage analysis to determine if this mutation is unique to this chromosome or represents a common polymorphism. Our linkage analysis showed that this mutation is not a common polymorphism and that it is also not an intrinsic part of the haplotype of the chromosome on which it was found. We also studied the interaction of nuclear proteins from erythroid and nonerythroid cells with the DNA sequences surrounding this mutation. We have shown by in vitro DNase I footprinting that this mutation falls within a region that is occupied by a novel DNA-binding protein that binds to this site in nuclear extracts from erythroid, but not nonerythroid cells. The binding of this nuclear protein to DNA appears to be dependent on GATA-1 binding to an adjacent GATA-1 site. We have also developed a new functional assay to compare the activity of the normal and mutant A gamma enhancer elements in erythroid cells. Analysis of the activity of the mutant enhancer shows that the mutation completely eliminates all enhancer activity in this assay. These findings suggest that this mutation of the A gamma enhancer on a chromosome that carries a partially inactivated beta-globin gene may be responsible for the increased expression of both gamma-globin genes seen in this condition.     

Uncoordinated expression of fibrinogen compared with thrombospondin and von Willebrand factor in maturing human megakaryocytes

The localization of three known alpha-granule proteins, thrombospondin (TSP), von Willebrand factor (vWF), and fibrinogen (Fg) has been studied in human megakaryocytes (MK) by immunofluorescence and immunoelectron microscopy. For this study, highly purified populations of MK were prepared from human bone marrow either by counterflow centrifugal elutriation or by cell culture from normal subjects and from two patients with megakaryoblastic leukemia. In normal bone marrow immature MK, TSP, and vWF were observed in the Golgi-associated vesicles and in small immature alpha-granules; in mature MK, they were found in the matrix of the mature large alpha-granules. Surprisingly, Fg was detected neither in the Golgi area, nor in the small precursors of alpha-granules; it was only found in the mature alpha-granules but this labeling was generally weaker than in blood platelets. In order to confirm these differences between the expression of Fg and vWF or TSP additional studies were performed on cultured maturing MK: immunofluorescent and ultrastructural immunogold labeling confirmed that vWF appeared early in the maturation while the same immature MK were negative for Fg. In the late maturation stage, the three proteins were detected in the alpha-granules. In order to know whether Fg was lately synthesized or endocytosed from the outside medium, normal MK were grown in the presence of either normal or afibrinogenemic plasma, and normal serum. Fg was detected only in the alpha-granules of MK grown in normal plasma. Similar results were observed with malignant MK, whose maturation was independent of the culture conditions. In conclusion, this study brings immunocytochemical evidence that vWF and TSP are synthesized by immature MK, whereas Fg appears later in the MK alpha-granules and its expression is dependent of the presence of an exogenous Fg source.     

Identification and characterization of a low-affinity granulocyte- macrophage colony-stimulating factor receptor on primary and cultured human melanoma cells

Hematopoietic growth factor receptors are present on cells of normal nonhematopoietic tissues such as endothelium and placenta. We previously demonstrated functional human granulocyte-macrophage colony- stimulating factor (GM-CSF) receptors on small cell carcinoma of the lung cell lines, and others have reported that certain solid tumor cell lines respond to GM-CSF in clonogenic assays. In the current study, we examine human melanoma cell lines and fresh specimens of melanoma to determine whether they have functional GM-CSF receptors. Scatchard analyses of 125I-GM-CSF equilibrium binding to melanoma cell lines showed a mean of 542 +/- 67 sites per cell with a kd of 0.72 +/- 0.14 nmol/L. Cross-linking studies in the melanoma cell line, M14, showed a major GM-CSF receptor species of 84,000 daltons. Under the conditions tested, the M14 cells did not have a proliferative response to GM-CSF in vitro, nor was any induction of primary response genes detected by Northern analysis in response to GM-CSF. Studies to determine internal translocation of the receptor-ligand complex indicated less than 10% of the 125I-GM-CSF internalized was specifically bound to receptors. Primary melanoma cells from five surgical specimens had GM-CSF receptors; Scatchard analysis was performed on one sample, showing 555 sites/cell with a kd of 0.23 nmol/L. These results indicate that human tumor cells may express a low-affinity GM-CSF receptor protein that localizes to the cell surface and binds ligand, but lacks functional components or accessory factors needed to transduce a signal.     

Production of genetically stable high-titer retroviral vectors that carry a human gamma-globin gene under the control of the alpha-globin locus control region

The ability to generate stable high-titer vectors that give rise to high levels of expression of transduced globin genes in erythroid cells is a prerequisite for effective retroviral-mediated globin gene therapy. The human beta-globin gene with its immediate flanking sequences does not contain all the regulatory elements necessary for regulated high-level and position-independent expression in erythroid cells. The regulatory element known as the beta-globin locus control region (BetaLCR) can provide a linked Beta-globin gene with these properties. However, addition of BetaLCR sequences to a retrovirus carrying a beta-globin gene increases its genetic instability. We have developed a new generation of retroviral vectors in which a human gamma- globin gene is placed under the control of the alphaLCR, the major regulatory element of the alpha-globin gene cluster. We demonstrate that these retroviruses are genetically stable in producer cell lines and can be produced at high titers that exceed 5 x 10(6) colony-forming units (CFU)/mL. In addition, we show that the transduced gamma-globin gene can be expressed in the adult erythroid environment of mouse erythroleukemia (MEL) cells at a level comparable to that of a single endogenous Betamaj-globin gene. These retroviruses can also transduce primary murine bone marrow progenitor cells as efficiently as retroviruses that carry the neomycin resistance (neor) gene. This new generation of globin retroviral vectors may prove useful for gene therapy of human beta-globin gene disorders such as sickle cell disease and beta-thalassemia.     

Autonomic neuropathy and transcutaneous oxymetry in diabetic lower extremities

Summary Transcutaneous oxygen tension is a useful method with which to assess the functional status of skin blood flow. The reduced values observed in diabetic patients have been interpreted as a consequence of peripheral vascular disease. However, diabetic patients show lower transcutaneous oxygen tension values than control subjects with equivalent degrees of peripheral vascular disease, suggesting that additional factors are involved. Since the autonomic nervous system influences peripheral circulation, we studied the relationship between autonomic neuropathy and foot transcutaneous oxymetry in non-insulin-dependent diabetic (NIDDM) patients without peripheral vascular disease. The following age-matched patients were selected and evaluated: control subjects, C, (n=20), NIDDM patients without autonomic neuropathy, D, (n=16) and with autonomic neuropathy, DN, (n=20). All diabetic patients showed lower transcutaneous oxygen tension values than control subjects, while no differences were observed between the diabetic patients with and without autonomic neuropathy. In addition the saturation index that increases in the presence of autonomic neuropathy does not correlate with foot TcPO₂. In conclusion autonomic neuropathy does not influence foot TcPO₂ and therefore it is unlikely that it contributes to development of foot lesions during induction of foot skin ischaemia.Abbreviations NIDDM Non-insulin-dependent diabetes mellitus - TcPO₂ transcutaneous oxymetry - A-V arterio-venous shunts - PVD peripheral vascular disease - HbA_1c glycated haemoglobin - SI saturation index