Abeta(1-40)-induced secretion of matrix metalloproteinase-9 results in sAPPalpha release by association with cell surface APP

To understand matrix metalloproteinase-9 (MMP-9) involvement in Alzheimer's disease, we examined mechanisms mediating increased expression of MMP-9 in the presence of Abeta(1-40) and the role of MMP-9 on amyloid precursor protein (APP) processing. Up-regulation of MMP-9 expressed by SK-N-SH cells in the presence of Abeta(1-40) was mediated by alpha(3)beta(1) and alpha(2)beta(1) integrin receptors. Overexpression of MMP-9 or treatment of HEK/APP695 cells with activated recombinant MMP-9 resulted in enhanced secretion of soluble APP (sAPPalpha), a product of alpha-secretase cleavage, and reduction of Abeta release. MMP-9 effect was enhanced by phorbol 12-mysistrate-13-acetate (PMA), an alpha-secretase activator and inhibited by EDTA or SB-3CT, an MMP-9 inhibitor. Additionally, immunoprecipitation and confocal microscopy demonstrated that MMP-9 and APP695 were associated on the cell surface. These results indicate that Abeta peptide increases MMP-9 secretion through integrins; MMP-9 then directly processes cell surface APP695 with an alpha-secretase like activity, substantially reducing the levels of secreted Abeta peptide.     

Age-related decline in nicotinic receptor availability with [(123)I]5-IA-85380 SPECT

Human postmortem studies have reported decreases with age in high affinity nicotine binding in brain. We investigated the effect of age on β₂-containing nicotinic acetylcholine receptor (β₂-nAChR) availability in eight brain regions of living human subjects using the ligand [¹²³I]5-IA-85380 ([¹²³I]5-IA) and single photon emission computed tomography (SPECT). Healthy, nonsmokers (N = 47) ranging in age from 18 to 85 were administered [¹²³I]5-IA using a bolus plus constant infusion paradigm and imaged 6–8 h later under equilibrium conditions. The effect of age on regional β₂-nAChR availability (V_T, regional brain activity/free plasma parent, a measure proportional to the binding potential) was analyzed using linear regression and Pearson's correlation (r). Age and regional β₂-nAChR availability were inversely correlated in seven of the eight brain regions analyzed, with decline ranging from 32% (thalamus) to 18% (occipital cortex) over the adult lifespan, or up to 5% per decade. These results in living human subjects corroborate postmortem reports of decline in high affinity nicotine binding with age and may aid in elucidating the role of β₂-nAChRs in cognitive aging.     

Reduced attentional capacity, but normal processing speed and shifting of attention in developmental dyslexia: Evidence from a serial task

We report the performance of a group of adult dyslexics and matched controls in an array-matching task where two strings of either consonants or symbols are presented side by side and have to be judged to be the same or different. The arrays may differ either in the order or identity of two adjacent characters. This task does not require naming – which has been argued to be the cause of dyslexics’ difficulty in processing visual arrays – but, instead, has a strong serial component as demonstrated by the fact that, in both groups, Reaction times (RTs) increase monotonically with position of a mismatch. The dyslexics are clearly impaired in all conditions and performance in the identity conditions predicts performance across orthographic tasks even after age, performance IQ and phonology are partialled out. Moreover, the shapes of serial position curves are revealing of the underlying impairment. In the dyslexics, RTs increase with position at the same rate as in the controls (lines are parallel) ruling out reduced processing speed or difficulties in shifting attention. Instead, error rates show a catastrophic increase for positions which are either searched later or more subject to interference. These results are consistent with a reduction in the attentional capacity needed in a serial task to bind together identity and positional information. This capacity is best seen as a reduction in the number of spotlights into which attention can be split to process information at different locations rather than as a more generic reduction of resources which would also affect processing the details of single objects.     

Quantitative description of overjet and overbite and their relationship with the craniofacial morphology.

OBJECTIVES: 1) To define the sagittal and vertical characteristics of anterior teeth in adults with normal occlusions; 2) to explore a relationship between the overbite and overjet; and 3) to relate overbite and overjet to the skeletal pattern. DESIGN: Prospective data collection. SETTING AND SAMPLE POPULATION: Ninety-two adult dental students from the Aristotle University of Thessaloniki (49 females and 43 males) with naturally occurring Class I occlusions. EXPERIMENTAL VARIABLE AND OUTCOME MEASURES: Cephalometric data were collected for overbite, overjet, and skeletal relationships. These were then correlated for potential association between front teeth and vertical and horizontal skeletal relationships. RESULTS: The overjet measures were equally distributed among men and women, but overbite was higher in women. Facial proportions were also bigger in men, but the Mediterranean face was bigger than Northern American Caucasian. The mandibular plane angle could be associated with either increased or decreased overjet and overbite. CONCLUSION: The overbite and overjet features of an occlusion cannot be predictably associated with any particular craniofacial pattern.     

A phase I clinical trial with monoclonal antibody ch806 targeting transitional state and mutant epidermal growth factor receptors

An array of cell-surface antigens expressed by human cancers have been identified as targets for antibody-based therapies. The great majority of these antibodies do not have specificity for cancer but recognize antigens expressed on a range of normal cell types (differentiation antigens). Over the past two decades, our group has analyzed thousands of mouse monoclonal antibodies for cancer specificity and identified a battery of antibodies with limited representation on normal human cells. The most tumor-specific of these antibodies is 806, an antibody that detects a unique epitope on the epidermal growth factor receptor (EGFR) that is exposed only on overexpressed, mutant, or ligand-activated forms of the receptor in cancer. In vitro immunohistochemical specificity analysis shows little or no detectable 806 reactivity with normal tissues, even those with high levels of wild-type (wt)EGFR expression. Preclinical studies have demonstrated that 806 specifically targets a subset of EGFR expressed on tumor cells, and has significant anti-tumor effects on human tumor xenografts, primarily through abrogation of signaling pathways. The present clinical study was designed to examine the in vivo specificity of a chimeric form of mAb 806 (ch806) in a tumor targeting/biodistribution/pharmacokinetic analysis in patients with diverse tumor types. ch806 showed excellent targeting of tumor sites in all patients, no evidence of normal tissue uptake, and no significant toxicity. These in vitro and in vivo characteristics of ch806 distinguish it from all other antibodies targeting EGFR.     

Low-dose total body irradiation (TBI) and fludarabine followed by hematopoietic cell transplantation (HCT) from HLA-matched or mismatched unrelated donors and postgrafting immunosuppression with cyclosporine and mycophenolate mofetil (MMF) can induce durable complete chimerism and sustained remissions in patients with hematological diseases

Toxicities of high-dose conditioning regimens have limited the use of conventional unrelated donor hematopoietic cell transplantation (HCT) to younger, medically fit patients. Based on preclinical studies, an HCT approach has been developed for elderly or medically infirm patients with HLA-matched or mismatched unrelated donors. In this study, 52 patients with hematological diseases were included. Most (88%) had preceding unsuccessful conventional HCT or refractory/advanced disease. Patients were treated with fludarabine 30 mg/m(2)/d from days -4 to -2, 2 Gy total body irradiation on day 0, cyclosporine at 6.25 mg/kg twice daily from day -3, and mycophenolate mofetil at 15 mg/kg twice daily from day 0. Durable donor chimerism was attained in 88% of the patients. By day 28, a median of 100% of CD56(+) cells were of donor origin. Granulocyte and T-cell donor chimerism increased to medians of 100% on day 56 and day 180 (range, 55%-100%), respectively. Acute GVHD, grade II, was seen in 42% (CI, 29%-56%); grade III in 8% (CI, 0%-15%); and grade IV in 13% (CI, 4%-23%) of patients; it was fatal in 9%. The 100-day transplantation-related mortality was 11%. Complete remissions, including molecular remissions, were seen in 45% of patients with measurable disease before transplantation. Mortality from disease progression was 27% at one year. With a median follow-up of 19 months, 18 of the 52 patients (35%) were alive and 25% were in remission. HCT from HLA-matched or mismatched unrelated donors can be performed with a reduced intensity conditioning regimen in patients ineligible for conventional HCT.     

HLA matching in allogeneic stem cell transplantation

PURPOSE OF REVIEW: The success of unrelated hematopoietic cell transplantation (HCT) is influenced by the degree of HLA compatibility between the donor and patient. The goal of this review is to summarize new findings in the field of immunogenetics and HCT from unrelated donors using myeloablative conditioning regimens. RECENT FINDINGS: Molecular typing methods can discriminate unique alleles encoded by HLA class I and II genes. Incompatibility of donor-recipient HLA alleles increases posttransplant complications including graft rejection, acute and chronic graft-versus-host disease, and mortality. These posttransplant risks increase with increasing numbers of HLA mismatches. The identification of permissible HLA mismatches may be aided by the use of functional assays. Nongenetic factors, including the stage of disease at the time of transplantation, may influence the effect of HLA mismatching on survival. SUMMARY: HLA alleles are functionally relevant. Unrelated HCT can be optimized by comprehensive and precise donor-recipient allele matching. For patients with high-risk diseases who lack matched donors, use of donors with a single HLA mismatch may permit early treatment before disease progression.     

Expression analysis of proteins involved in the non homologous end joining DNA repair mechanism, in the bone marrow of adult de novo myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are characterized by genetic instability which is associated with abnormal DNA repair mechanisms. The most lethal type of DNA damage are double strand DNA breaks (DSBs), which are mainly repaired by Non Homologous End Joining Mechanism (NHEJ), whose core enzyme components include the Ku70/Ku80 heterodimer, DNA–PKcs, XRCC4 and DNA Ligase IV. The aim of the present study was the analysis of expression of proteins required for NHEJ in bone marrow cells of adult de novo MDS and their association with clinical characteristics and prognosis. Our analysis included 48 cases of MDS; 19 RA, 5 RARS, 19 RAEB, 3 RAEB-T, 1 CMML, 1 transformation to AML according to FAB classification. The expression of the enzymes Ku70, Ku80, XRCC4, DNA-PKcs and Ligase IV was determined by Western Blotting. The mean Ligase IV expression value was significantly lower in MDS patients compared to normal controls (0.53 vs. 0.78, p?=?0.03). A negative correlation was found between karyotype risk group and Ligase IV values. (p?=?0.05). Moreover, Ku70 expression levels were significantly lower in patients with a good prognosis karyotype (p?=?0.04). Furthermore, a negative correlation between Ku70 expression values and Hb levels was observed (p?=?0.04). Finally, a positive correlation was observed between enzyme Ku70 expression values and level of blasts (p?=?0.04). Our findings suppor-t a potential role of NHEJ enzyme Ligase IV in the pathogenesis of MDS. Larger numbers of cases need to be screened in order to draw definite conclusion.     

Favorable outcomes with alemtuzumab-conditioned unrelated donor stem cell transplantation in adults with high-risk Philadelphia chromosome-negative acute lymphoblastic leukemia in first complete remission

Background

Approximately 40% of adults with Philadelphia chromosome-negative acute lymphoblastic leukemia achieve long-term survival following unrelated donor hematopoietic stem cell transplantation in first complete remission but severe graft-versus-host disease remains a problem affecting survival. Although T-cell depletion abrogates graft-versus-host disease, the impact on disease-free survival in acute lymphoblastic leukemia is not known.

Design and Methods

We analyzed the outcome of 48 adults (median age 26 years) with high-risk, Philadelphia-chromosome-negative acute lymphoblastic leukemia undergoing T-cell depleted unrelated donor-hematopoietic stem cell transplantation (67% 10 of 10 loci matched) in first complete remission reported to the British Society of Blood and Marrow Transplantation Registry from 1993 to 2005.

Results

T-cell depletion was carried out by in vivo alemtuzumab administration. Additional, ex vivo T-cell depletion was performed in 21% of patients. Overall survival, disease-free survival and non-relapse mortality rates at 5 years were 61% (95% CI 46–75), 59% (95% CI 45–74) and 13% (95% CI 3–25), respectively. The incidences of grades II–IV and III–IV acute graft-versus-host disease were 27% (95% CI 16–44) and 10% (95% CI 4–25), respectively. The actuarial estimate of extensive chronic graft-versus-host disease at 5 years was 22% (95%CI 13–38). High-risk cytogenetics at diagnosis was associated with a lower 5-year overall survival (47% (95% CI 27–71) vs. 68% (95% CI 44–84), p=0.045).

Conclusions

T-cell depleted hematopoietic stem cell transplantation from unrelated donors can result in good overall survival and low non-relapse mortality for adults with high-risk acute lymphoblastic leukemia in first complete remission and merits prospective evaluation.     

Reduced intensity conditioning allogeneic stem cell transplantation for Hodgkin’s lymphoma: identification of prognostic factors predicting outcome

Background

The role of reduced intensity conditioning allogeneic stem transplantation (RICalloSCT) in the management of patients with Hodgkin’s lymphoma remains controversial.

Design and Methods

To further define its role we have conducted a retrospective analysis of 285 patients with HL who underwent a RICalloSCT in order to identify prognostic factors that predict outcome. Eighty percent of patients had undergone a prior autologous stem cell transplantation and 25% had refractory disease at transplant.

Results

Non-relapse mortality was associated with chemorefractory disease, poor performance status, age >45 and transplantation before 2002. For patients with no risk factors the 3-year non-relapse mortality rate was 12.5% compared to 46.2% for patients with 2 or more risk factors. The use of an unrelated donor had no adverse effect on the non-relapse mortality. Acute graft versus host disease (aGVHD) grades II–IV developed in 30% and chronic GVHD in 42%. The development of cGVHD was associated with a lower relapse rate. The disease progression rate at one and five years was 41% and 58.7% respectively and was associated with chemorefractory disease and extent of prior therapy. Donor lymphocyte infusions were administered to 64 patients for active disease of whom 32% showed a clinical response. Eight out of 18 patients receiving donor lymphocyte infusions alone had clinical responses. Progression-free and overall survival were both associated with performance status and disease status at transplant. Patients with neither risk factor had a 3-year PFS and overall survival of 42% and 56% respectively compared to 8% and 25% for patients with one or more risk factors. Relapse within six months of a prior autologous transplant was associated with a higher relapse rate and a lower progression-free.

Conclusions

This analysis identifies important clinical parameters that may be useful in predicting the outcome of RICaIICalloSCT in Hodgkin’s lymphoma.