Showing papers by "University of Milan published in 2000"

Criteria for cure of acromegaly: a consensus statement.

Abstract: In February 1999, a workshop was held in Cortina, Italy to develop a consensus defining the criteria for cure of acromegaly. The workshop was sponsored by the University of Brescia and hosted by the Italian Society of Endocrinology. Invited international participants included endocrinologists, neurosurgeons, and radiotherapists skilled in the management of acromegaly. This statement summarizes the consensus achieved in these discussions.

Alcohol and coronary heart disease: a meta-analysis.

Abstract: Objective. To estimate parameters of the function relating alcohol consumption with the risk of coronary heart disease and to identify the sources of heterogeneity in the parameter estimates. Methods. A search of the epidemiological literature from 1966 to 1998 was performed using several bibliographic databases. Meta-regression models were fitted to evaluate non-linear effects of alcohol intake on the relative risk. The effects of some characteristics of the studies, including an index of their quality, were considered as putative sources of heterogeneity of the estimates. Publication bias was also investigated. Findings. Among the 196 initially reviewed articles, 51 were selected. Since qualitative characteristics of the studies were significant sources of heterogeneity, the pooled dose-response functions were based on the 28 cohort studies with higher quality. Risk decreased from 0 to 20 g/day (RR = 0.80; 95% CI: 0.78, 0.83); there was evidence of a protective effect up to 72 g/day (RR = 0.96; 95% CI: 0.92, 1.00) and increased risk above ≥ 89 g/day (RR = 1.05; 95% CI: 1.00, 1.11). Lower protective effects and harmful effects were found in women, in men living in countries outside the Mediterranean area and in studies where fatal events were used as the outcome. Evidence of publication bias for moderate intakes and of heterogeneity of the estimates across studies for higher intakes were found. Conclusions. The degree of protection from moderate doses of alcohol should be reconsidered. Further research investigating the effect of drinking patterns on the risk of coronary heart disease should be performed. Caution in making general recommendations is needed.

Transcriptional repression by AtMYB4 controls production of UV-protecting sunscreens in Arabidopsis.

Abstract: An Arabidopsis thaliana line that is mutant for the R2R3 MYB gene, AtMYB4, shows enhanced levels of sinapate esters in its leaves. The mutant line is more tolerant of UV-B irradiation than wild type. The increase in sinapate ester accumulation in the mutant is associated with an enhanced expression of the gene encoding cinnamate 4-hydroxylase, which appears to be the principal target of AtMYB4 and an effective rate limiting step in the synthesis of sinapate ester sunscreens. AtMYB4 expression is downregulated by exposure to UV-B light, indicating that derepression is an important mechanism for acclimation to UV-B in A.thaliana. The response of target genes to AtMYB4 repression is dose dependent, a feature that operates under physiological conditions to reinforce the silencing effect of AtMYB4 at high activity. AtMYB4 works as a repressor of target gene expression and includes a repression domain. It belongs to a novel group of plant R2R3 MYB proteins involved in transcriptional silencing. The balance between MYB activators and repressors on common target promoters may provide extra flexibility in transcriptional control.

Regulation of apoptosis at cell division by p34cdc2 phosphorylation of survivin.

Abstract: The interface between apoptosis (programmed cell death) and the cell cycle is essential to preserve homeostasis and genomic integrity. Here, we show that survivin, an inhibitor of apoptosis over-expressed in cancer, physically associates with the cyclin-dependent kinase p34(cdc2) on the mitotic apparatus, and is phosphorylated on Thr(34) by p34(cdc2)-cyclin B1, in vitro and in vivo. Loss of phosphorylation on Thr(34) resulted in dissociation of a survivin-caspase-9 complex on the mitotic apparatus, and caspase-9-dependent apoptosis of cells traversing mitosis. These data identify survivin as a mitotic substrate of p34(cdc2)-cyclin B1 and suggest that survivin phosphorylation on Thr(34) may be required to preserve cell viability at cell division. Manipulation of this pathway may facilitate the elimination of cancer cells at mitosis.

Dominant phenotypes produced by the HD mutation in STHdhQ111 striatal cells

Abstract: Lengthening a glutamine tract in huntingtin confers a dominant attribute that initiates degeneration of striatal neurons in Huntington's disease (HD) To identify pathways that are candidates for the mutant protein's abnormal function, we compared striatal cell lines established from wild-type and Hdh(Q111) knock-in embryos Alternate versions of full-length huntingtin, distinguished by epitope accessibility, were localized to different sets of nuclear and perinuclear organelles involved in RNA biogenesis and membrane trafficking However, mutant STHdh(Q111) cells also exhibited additional forms of the full-length mutant protein and displayed dominant phenotypes that did not mirror phenotypes caused by either huntingtin deficiency or excess These phenotypes indicate a disruption of striatal cell homeostasis by the mutant protein, via a mechanism that is separate from its normal activity They also support specific stress pathways, including elevated p53, endoplasmic reticulum stress response and hypoxia, as potential players in HD

Vitamin D3 Affects Differentiation, Maturation, and Function of Human Monocyte-Derived Dendritic Cells

Abstract: We studied the effects of 1alpha,25-dihydroxyvitamin D3 (1alpha, 25-(OH)2D3) on differentiation, maturation, and functions of dendritic cells (DC) differentiated from human monocytes in vitro in the presence of GM-CSF and IL-4 for 7 days. Recovery and morphology were not affected by 1alpha,25-(OH)2D3 up to 100 nM. DC differentiated in the presence of 10 nM 1alpha,25-(OH)2D3 (D3-DC) showed a marked decrease in the expression of CD1a, while CD14 remained elevated. Mannose receptor and CD32 were significantly increased, and this correlated with an enhancement of endocytic activity. Costimulatory molecules such as CD40 and CD86 were slightly decreased or nonsignificantly affected (CD80 and MHC II). However, after induction of DC maturation with LPS or incubation with CD40 ligand-transfected cells, D3-DC showed marginal increases in MHC I, MHC II, CD80, CD86, CD40, and CD83. The accessory cell function of D3-DC in classical MLR was also inhibited. Moreover, allogeneic T cells stimulated with D3-DC were poor responders in a second MLR to untreated DC from the same or an unrelated donor, thus indicating the onset of a nonspecific hyporesponsivity. In conclusion, our data suggest that 1alpha,25-(OH)2D3 may modulate the immune system, acting at the very first step of the immune response through the inhibition of DC differentiation and maturation into potent APC.

Role of Adenine Nucleotide Translocator 1 in mtDNA Maintenance

Abstract: Autosomal dominant progressive external ophthalmoplegia is a rare human disease that shows a Mendelian inheritance pattern, but is characterized by large-scale mitochondrial DNA (mtDNA) deletions. We have identified two heterozygous missense mutations in the nuclear gene encoding the heart/skeletal muscle isoform of the adenine nucleotide translocator (ANT1) in five families and one sporadic patient. The familial mutation substitutes a proline for a highly conserved alanine at position 114 in the ANT1 protein. The analogous mutation in yeast caused a respiratory defect. These results indicate that ANT has a role in mtDNA maintenance and that a mitochondrial disease can be caused by a dominant mechanism.

Insights into the reasons for discontinuation of the first highly active antiretroviral therapy (HAART) regimen in a cohort of antiretroviral naïve patients.

Abstract: Objective: To evaluate the frequency of discontinuation of the first highly active antiretroviral regimen (HAART) and the factors predictive of discontinuing for toxicity and failure in a population-based cohort of HIV-positive individuals in Italy, naive from antiretrovirals at enrolmentMethods: The study population consisted of individuals who initiated HAART and had at least one follow-up visit The primary end-points were discontinuation of any component of HAART for drug toxicity and discontinuation for failure Survival analyses were performed to identify predictive factors for reaching the two end pointsResults: Eight hundred and sixty-two individuals initialed HAART; in 727 of them (843%) this consisted of two nucleoside reverse transcriptase inhibitors (NRTI) and one protease inhibitor (PI) Over a median follow-up of 45 weeks, 312 patients (362%) discontinued therapy: 182 (211%) discontinued due to toxicity, 44 (51%) due to failure The probability of discontinuing HAART at 1 year was 255% [95% confidence interval (Cl), 219-289] due to toxicity and 76% (95% Cl, 49-103) due to failure Independent factors associated with discontinuation for toxicity were: gender [relative hazard (RH) = 051; 95% Cl, 032-080 for men versus women], type of treatment (indinavir-containing regimens, RH = 194; 95% Cl, 110-341 and ritonavir-containing regimens, RH = 383; 95% Cl, 209-703 versus hard-gell saquinavir) and time spent on treatment (RH = 089; 95% Cl, 080-098 for each additional month) Discontinuation due to failure was independently associated with the most recent HIV-RNA (RH = 320; 959/0 Cl, 174-588 for log(10) copies/ml higher), and with type of treatment (indinavir-containing regimens, RH = 021; 95% Cl, 006-078 and ritonavir-containing regimens, RH = 023; 95% Cl, 004-126 Versus hard-gell saquinavir)Conclusions: If the current HAART regimen caused no toxicity, less than 10% of naive patients discontinue their first HAART regimen because of failure after 1 year from starting therapy (C) 2000 Lippincatt Williams & Wilkins

Correlation between Molecular Packing and Optical Properties in Different Crystalline Polymorphs and Amorphous Thin Films of mer-Tris(8-hydroxyquinoline)aluminum(III)

Abstract: Since 1987, high-luminance low-voltage driven devices based on tris(8-hydroxyquinoline)aluminum(III) (Alq3) opened the route to design low-cost large area displays and illuminators. Despite the large number of studies devoted to this material, very little is known about its basic structural and optical properties in the solid state. Therefore, we have investigated the structure(s) and the correlation between intermolecular interactions and optical properties in various Alq3 systems, including solution, amorphous thin films, and different crystalline forms. Two novel unsolvated polymorphs of Alq3, namely, α-Alq3 and β-Alq3, have been synthesized and their crystalline structures determined from X-ray diffraction data on powders (α) and single crystals (β). Crystals of α-Alq3 are triclinic, space group P-1, a = 6.2586(8) A, b = 12.914(2) A; c = 14.743(2) A, α = 109.66(1)°; β = 89.66(1)°, and γ = 97.68(1)°; crystals of β-Alq3 are triclinic, space group P-1, a = 8.4433(6) A, b = 10.2522(8) A; c = 13.1711(10) A...

The Minimal Entropy Martingale Measure and the Valuation Problem in Incomplete Markets

Abstract: Let χ be a family of stochastic processes on a given filtered probability space (Ω, F, (Ft)t∈T, P) with T⊆R+. Under the assumption that the set Me of equivalent martingale measures for χ is not empty, we give sufficient conditions for the existence of a unique equivalent martingale measure that minimizes the relative entropy, with respect to P, in the class of martingale measures. We then provide the characterization of the density of the minimal entropy martingale measure, which suggests the equivalence between the maximization of expected exponential utility and the minimization of the relative entropy.

A cultural effect on brain function.

Abstract: We present behavioral and anatomical evidence for a multi-component reading system in which different components are differentially weighted depending on culture-specific demands of orthography Italian orthography is consistent, enabling reliable conversion of graphemes to phonemes to yield correct pronunciation of the word English orthography is inconsistent, complicating mapping of letters to word sounds In behavioral studies, Italian students showed faster word and non-word reading than English students In two PET studies, Italians showed greater activation in left superior temporal regions associated with phoneme processing In contrast, English readers showed greater activations, particularly for non-words, in left posterior inferior temporal gyrus and anterior inferior frontal gyrus, areas associated with word retrieval during both reading and naming tasks

Chromosomal aberrations in lymphocytes predict human cancer independently of exposure to carcinogens

Abstract: An increased risk of cancer in healthy individuals with high levels of chromosomal aberrations (CAs) in peripheral blood lymphocytes has been described in recent epidemiological studies. This association did not appear to be modified by sex, age, country, or time since CA test, whereas the role played by exposure to carcinogens is still uncertain because of the requisite information concerning occupation and lifestyle was lacking. We evaluated in the present study whether CAs predicted cancer because they were the result of past exposure to carcinogens or because they were an intermediate end point in the pathway leading to disease. A nested case-control study was performed on 93 incident cancer cases and 62 deceased cancer cases coming from two prospective cohort studies performed in Nordic countries (Denmark, Finland, Norway, and Sweden) and Italy. For each case, four controls matched by country, sex, year of birth, and year of CA test were randomly selected. Occupational exposure and smoking habit were assessed by a collaborative group of occupational hygienists. Logistic regression models indicated a statistically significant increase in risk for subjects with a high level of CAs compared to those with a low level in the Nordic cohort (odds ratio, 2.35; 95% confidence interval, 1.31-4.23) and in the Italian cohort (odds ratio, 2.66; 95% confidence interval, 1.26-5.62). These estimates were not affected by the inclusion of occupational exposure level and smoking habit in the regression model. The risk for high versus low levels of CAs was similar in subjects heavily exposed to carcinogens and in those who had never, to their knowledge, been exposed to any major carcinogenic agent during their lifetime, supporting the idea that chromosome damage itself is involved in the pathway to cancer. The results have important ramifications for the understanding of the role played by sporadic chromosome damage for the origin of neoplasia-associated CAs.

How to measure baroreflex sensitivity: from the cardiovascular laboratory to daily life.

Abstract: Arterial baroreflex function in humans is commonly assessed through a number of laboratory tests based on quantification of the reflex responses in heart rate or blood pressure to external stimuli applied to the cardiovascular system. Evidence is available that these laboratory estimates of baroreflex sensitivity have both pathophysiological and clinical relevance. Indeed, a number of studies have shown that the sensitivity of the baroreceptor-heart rate reflex may have a prognostic value in myocardial infarction, heart failure and diabetic patients, where mortality seems to be inversely related to the sensitivity of cardiac baroreflex modulation. A deeper insight into the features of daily-life baroreflex cardiovascular control has been offered more recently by techniques based on computer analysis of spontaneous blood pressure and heart rate fluctuations. This innovative approach allows spontaneous baroreflex sensitivity to be assessed in real life conditions, with no need for external stimulation of the patient as required by the older laboratory techniques. This review will briefly survey the methods most widely used to assess baroreflex function in humans, in the laboratory and in daily life.

Gene therapy of experimental brain tumors using neural progenitor cells

Abstract: Glioblastomas, the most frequent and malignant of primary brain tumors, have a very poor prognosis. Gene therapy of glioblastomas is limited by the short survival of viral vectors and by their difficulty in reaching glioblastoma cells infiltrating the brain parenchyma. Neural stem/progenitor cells can be engineered to produce therapeutic molecules and have the potential to overcome these limitations because they may travel along the white matter, like neoplastic cells, and engraft stably into the brain. Retrovirus-mediated transfer of the gene for interleukin-4 is an effective treatment for rat brain glioblastomas. Here, we transferred the gene for interleukin-4 into C57BL6J mouse primary neural progenitor cells and injected those cells into established syngeneic brain glioblastomas. This led to the survival of most tumor-bearing mice. We obtained similar results by implanting immortalized neural progenitor cells derived from Sprague-Dawley rats into C6 glioblastomas. We also documented by magnetic resonance imaging the progressive disappearance of large tumors, and detected 5-bromodeoxyuridine-labeled progenitor cells several weeks after the injection. These findings support a new approach for gene therapy of brain tumors, based on the grafting of neural stem cells producing therapeutic molecules.

Wild-Type Huntingtin Protects from Apoptosis Upstream of Caspase-3

Abstract: Expansion of a polyglutamine sequence in the N terminus of huntingtin is the gain-of-function event that causes Huntington's disease. This mutation affects primarily the medium-size spiny neurons of the striatum. Huntingtin is expressed in many neuronal and non-neuronal cell types, implying a more general function for the wild-type protein. Here we report that wild-type huntingtin acts by protecting CNS cells from a variety of apoptotic stimuli, including serum withdrawal, death receptors, and pro-apoptotic Bcl-2 homologs. This protection may take place at the level of caspase-9 activation. The full-length protein also modulates the toxicity of the poly-Q expansion. Cells expressing full-length mutant protein are susceptible to fewer death stimuli than cells expressing truncated mutant huntingtin.

A test of crystal structure prediction of small organic molecules

Abstract: A collaborative workshop was held in May 1999 at the Cambridge Crystallographic Data Centre to test how well currently available methods of crystal structure prediction perform when given only the atomic connectivity for an organic compound. A blind test was conducted on a selection of four compounds and a wide range of methodologies representing the principal computer programs currently available were used. There were 11 participants who were allowed to propose at most three structures for each compound. No program gave consistently reliable results. However, seven proposed structures were close to an experimental one and were classified as `correct'. One compound occurred in two polymorphs, but only one form was predicted correctly among the calculated structures. The basic problem with lattice energy based methods of crystal structure prediction is that many structures are found within a few kJ mol−1 of the global minimum. The fine detail of the force-field methodology and parametrization influences the energy ranking within each method. Nevertheless, present methods may be useful in providing a set of structures as possible polymorphs for a given molecular structure.

Acetylene cyclotrimerization on supported size-selected Pd-n clusters (1 <= n <= 30): one atom is enough!

Abstract: We studied the cyclotrimerization of acetylene on size-selected Pdn clusters (1 ≤ n ≤ 30) supported on thin MgO(100) films by thermal desorption and Fourier transform infrared spectroscopy. Surprisingly, the production of benzene is already observed on a single palladium atom at low temperature (300 K). Using density functional theory (DFT) calculations we show that free inert Pd atoms are activated by charge transfer from defect sites of the MgO substrate upon deposition. For larger clusters (7 ≤ n ≤ 30) benzene is additionally produced at a temperature of 430 K and our results suggest the existence of a critical ensemble of seven palladium atoms for this high-temperature reaction mechanism.

Sox2 regulatory sequences direct expression of a (beta)-geo transgene to telencephalic neural stem cells and precursors of the mouse embryo, revealing regionalization of gene expression in CNS stem cells.

Abstract: Sox2 is one of the earliest known transcription factors expressed in the developing neural tube. Although it is expressed throughout the early neuroepithelium, we show that its later expression must depend on the activity of more than one regionally restricted enhancer element. Thus, by using transgenic assays and by homologous recombination-mediated deletion, we identify a region upstream of Sox2 (−5.7 to −3.3 kb) which can not only drive expression of a (beta)-geo transgene to the developing dorsal telencephalon, but which is required to do so in the context of the endogenous gene. The critical enhancer can be further delimited to an 800 bp fragment of DNA surrounding a nuclease hypersensitive site within this region, as this is sufficient to confer telencephalic expression to a 3.3 kb fragment including the Sox2 promoter, which is otherwise inactive in the CNS. Expression of the 5.7 kb Sox2(beta)-geo transgene localizes to the neural plate and later to the telencephalic ventricular zone. We show, by in vitro clonogenic assays, that transgene-expressing (and thus G418-resistant) ventricular zone cells include cells displaying functional properties of stem cells, i.e. self-renewal and multipotentiality. We further show that the majority of telencephalic stem cells express the transgene, and this expression is largely maintained over two months in culture (more than 40 cell divisions) in the absence of G418 selective pressure. In contrast, stem cells grown in parallel from the spinal cord never express the transgene, and die in G418. Expression of endogenous telencephalic genes was similarly observed in long-term cultures derived from the dorsal telencephalon, but not in spinal cord-derived cultures. Thus, neural stem cells of the midgestation embryo are endowed with region-specific gene expression (at least with respect to some networks of transcription factors, such as that driving telencephalic expression of the Sox2 transgene), which can be inherited through multiple divisions outside the embryonic environment.

Promoter Methylation and Silencing of the Retinoic Acid Receptor-β Gene in Lung Carcinomas

Abstract: Background: Retinoic acid plays an important role in lung development and differentiation, acting primarily via nuclear receptors encoded by the retinoic acid receptor-β (RARβ) gene. Because receptor isoforms RARβ2 and RARβ4 are repressed in human lung cancers, we investigated whether methylation of their promoter, P2, might lead to silencing of the RARβ gene in human lung tumors and cell lines. Methods: Methylation of the P2 promoter from small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) cell lines and tumor samples was analyzed by the methylation-specific polymerase chain reaction (PCR). Expression of RARβ2 and RARβ4 was analyzed by reverse transcription-PCR. Loss of heterozygosity (LOH) was analyzed by PCR amplification followed by electrophoretic separation of PCR products. Statistical differences were analyzed by Fisher's exact test with continuity correction. Results: The P2 promoter was methylated in 72% (63 of 87) of SCLC and in 41% (52 of 127) of NSCLC tumors and cell lines, and the difference was statistically significant (two-sided P<.001). By contrast, in 57 of 58 control samples, we observed only the unmethylated form of the gene. Four tumor cell lines with unmethylated promoter regions expressed both RARβ2 and RARβ4. Four tumor lines with methylated promoter regions lacked expression of these isoforms, but demethylation by exposure to 5-aza-2'-deoxycytidine restored their expression. LOH at chromosome 3p24 was observed in 100% (13 of 13) of SCLC lines and 67 % (12 of 18) of NSCLC cell lines, and the difference was statistically significant (two-sided P = .028). Conclusions: Methylation of the RARβ P2 promoter is one mechanism that silences RARβ2 and RARβ4 expression in many lung cancers, particularly SCLC. Chemical demethylation is a potential approach to lung cancer therapy.

Differential viral protein expression in Kaposi's sarcoma-associated herpesvirus-infected diseases: Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease.

Abstract: Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is linked to KS, primary effusion lymphomas (PEL), and a subset of multicentric Castleman's disease (MCD). Transcript mapping studies using PEL cell lines have allowed preliminary classification of viral gene expression into constitutive (class I) and inducible (class II/III) categories. To determine whether viral gene expression differs in vivo, we examined tissue sections of KSHV-infected disorders, using specific antibodies against proteins that are representative of the different expression classes of KSHV genes. ORF73/LANA appears to be a surrogate marker for KSHV infection because it is constitutively expressed in vitro and in vivo in all KSHV-infected cells. Expression of vIRF1, vIL6, and PF-8 proteins in the infected B cells of MCD lymph nodes reproduces the expression pattern observed in TPA-stimulated KSHV-infected B-cell lines. In contrast, the protein expression of the inducible viral genes that we tested in KS and PEL biopsies is restricted to PF-8 and vIL6, respectively. The tightly restricted expression of KSHV proteins in vivo differs from the dysregulated expression of inducible KSHV genes in vitro and suggests that viral gene expression in KSHV-infected cell lines does not accurately reflect what occurs in diseased tissues. These differences may be related to either cell-specific or immune restriction of viral replication.

Multiple gestation pregnancy

Abstract: The ESHRE Capri Workshop Group* rates in most circumstances. Embryo reduction involves extremely difficult decisions for infertile couples and should Correspondence should be addressed to Professor P.G. Crosignani, be used only as a last resort. Assisted reproductive treatClinica Ostetrica e Ginecologica I, Facolta de Medicina e Chirurgia, Universita Degli Studi di Milano, Via Commenda, ment centres and registries should express cycle results as 12-20122 Milano, Italy. E-mail: piergiorgio.crosignani@unimi.it the proportion of singleton live births; twin and triplet rates should be reported separately as complications of the Multiple gestation pregnancy rates are high in assisted procedures. Reducing the multiple gestation pregnancy reproductive treatment cycles because of the perceived need rate should be a high priority for assisted reproductive to stimulate excess follicles and transfer excess embryos in treatment programmes, despite the pressure from some order to achieve reasonable pregnancy rates. Perinatal patients to transfer more embryos in order to improve mortality rates are, however, 4-fold higher for twins and success. If nothing is done, public concern may lead 6-fold higher for triplets than for singletons. Since the goal to legislation in many countries, a step that would be of infertility therapy is a healthy child, and multiple unnecessary if assisted reproductive treatment programmes gestation puts that goal at risk, multiple pregnancy must be and registries took suitable steps to reduce multiple pregregarded as a serious complication of assisted reproductive nancy rates. treatment cycles. The 1999 ESHRE Capri Workshop