Charge-fluctuation contribution to the Raman response in superconducting cuprates

We calculate the Raman response contribution due to soft collective modes, finding a strong dependence on the photon polarizations and on the characteristic wave vectors of the modes. We compare our results with recent Raman spectroscopy experiments in underdoped cuprates, La2-xSrxCuO4 and (Y1.97Ca0.3)Ba2CuO6.05, where anomalous low-energy peaks are observed, which soften upon lowering the temperature. We show that the specific dependence on doping and on photon polarizations of these peaks can naturally arise from charge collective excitations at finite wavelength.

Electron-phonon interaction close to a Mott transition

The effect of Holstein electron-phonon interaction on a Hubbard model close to a Mott-Hubbard transition at half filling is investigated by means of dynamical mean-field theory. We observe a reduction of the effective mass that we interpret in terms of a reduced effective repulsion. When the repulsion is rescaled to take into account this effect, the quasiparticle low-energy features are unaffected by the electron-phonon interaction. Phonon features are only observed within the high-energy Hubbard bands. The lack of electron-phonon fingerprints in the quasiparticle physics can be explained interpreting the quasiparticle motion in terms of rare fast processes.

Phase separation close to the density-driven Mott transition in the Hubbard-Holstein model

The density-driven Mott transition is studied by means of dynamical mean-field theory in the Hubbard-Holstein model, where the Hubbard term leading to the Mott transition is supplemented by an electron-phonon (e-ph) term. We show that an intermediate e-ph coupling leads to a first-order transition at T=0, which is accompanied by a phase separation between a metal and an insulator. The compressibility in the metallic phase is substantially enhanced. At quite larger values of the coupling, a polaronic phase emerges coexisting with a nonpolaronic metal.

Immune system alterations in lung cancer patients

The immune system plays an important role in the defense against neoplastic disease and immune responses show temporal changes related to circadian variations of antibodies, total lymphocytes in the peripheral blood and cell mediated immune responses. In this study we evaluate. lymphocyte subpopulations and interleukin-2 (IL-2) serum levels in peripheral blood samples collected at four-hour intervals for 24-hours starting at 06.00 h from ten healthy subjects aged 65-79 years (mean age +/- s.e. 67.28 +/- 3.11) and from ten subjects suffering from untreated non small cell lung cancer aged 65-78 years (mean age +/- s.e. 68.57 +/- 1.81). Areas under the curve, mean diurnal levels (mean of 06.00-10.00-14.00 h) and mean nocturnal levels (mean of 18.00-22.00-02.00 h) were calculated, and the presence of circadian rhythmicity was evaluate. When we compared AUC values there was a decrease in CD8bright (T suppressor subset) and an increase in CD16 (natural killer cells) and of IL-2 serum levels in cancer patients. When we compared mean diurnal levels, CD8 (T suppressor/cytotoxic subset) and CD8bright levels were lower, and CD16 levels were higher in cancer patients. When we compared mean nocturnal levels, CD16 and CD25 (T and B activated lymphocytes with expression of the a chain of IL-2 receptor) levels were higher, while CD8, CD8bright, CD20 (total B-cells), TcRd1 (epitope of the constant domain of d chain of T-cell receptor 1) and dTcS1 (epitope of the variable domain of d chain of T-cell receptor1) levels were lower in cancer patients. A clear circadian rhythm was validated for the time-qualified changes in CD4, CD20, HLA-DR with acrophase at night, and CD8, CD8 bright, CD8 dim, CD16, TcRd1 and dTcS1 with acrophase in the morning in the control group. A clear circadian rhythm was validated for the time-qualified changes in CD4 with acrophase at night, in the group of cancer patients. Results obtained in our study show that lung cancer is associated with anomalies of proportion and circadian variations of lymphocyte subsets that must be considered when adoptive immunotherapy has to be planned.

[Case report: Acro-necrosis of the upper limbs caused by gemcitabine therapy]

INTRODUCTION

Even if infrequent, a digital necrosis after chemotherapy can occur in cancer patients. The gemcitabine is generally well tolerate; the cutaneous toxic ulcerations only in 0.3% of the cases induces the suspension of the treatment.

CLINICAL CASE

A 70 year old patient, female, with a bladder cancer, after a trans-urethral resection, is submitted to adjuvant chemotherapy with Gemcitabine 1700 mg (total dose/die), with administration in the days 1st and 8th, while in the 15th day was not effected because, to distance of 3-4 days from the second administration, appear paresthesies of the fingers of the hands, together with Raynaud type phenomenon, 38-39 degrees C intermittent fever, digital necrosis and fingertips gangrene. Laboratory: (Normal): RF; AutoAb: AMA, ASMA, APCA, anti-DNA; ENA; lupus anti-coagulant; Ab-anti-cardiolipin; C3-C4, CIC; homocysteine, anti-thrombin, protein C, protein S, mutation of the factor V of Leiden, plasminogen, alfa 2-antiplasmin. (Altered): Auto-antibody: ANA (on Hep-2): positive (title 1/160, speckled pattern), cryoglobulin positive, ESR 29; Instrumental examinations: Superior Limbs Angiograpy: Occlusion of the digital arteries proper of 2nd, 3rd and 4th finger of the hands. Electromyography Inferior Arts: normal. Superior Arts: bilateral suffering of the median nerve at the carpal tunnel. Biopsy of the hand cutis: Hyperkeratosis, acanthosis and papillomatosis of the skin. Arterial vases with signs of endothelioangiitis and aspecific inflammation.

CONCLUSIONS

Even if acronecrosis of the superior limbs is a rare effect of the gemcitabine, we would recommend particular caution in the administration of this drug in patient with known autoimmune disorders.

Screening for silent myocardial ischaemia in type 2 diabetic patients with additional atherogenic risk factors: applicability and accuracy of the exercise stress test

OBJECTIVE

Coronary artery disease (CAD), a major cause of mortality in patients with type 2 diabetes (T2D), is often diagnosed late because of silent myocardial ischaemia (SMI). Exercise electrocardiogram testing (ECG) stress is the most utilized screening test for SMI. Its applicability and accuracy, which have never been reported in asymptomatic high-risk T2D patients, have been investigated in this study.

DESIGN

A cross-sectional study with coronary angiography as the gold standard for detecting CAD was used.

METHODS

Two hundred and six consecutive T2D patients, without symptoms and resting ECG signs of ischaemia but with peripheral vascular disease (PVD) and/or > or = two atherogenic factors, were studied. Ischaemia at ECG stress was indicated by horizontal or downsloping ST segment depression > or =1 mm at 0.08 s after the J point. CAD was defined by stenosis > or =70%.

RESULTS

Only 141/206 (68%) patients had a diagnostic test: 27 (19%) tested positive and 114 (81%) tested negative. Coronary angiography in 71 patients (the 27 who tested positive and 44 randomly selected patients who tested negative) indicated a CAD prevalence of 29% and the ECG stress accuracy was 79%. 'False negative' patients (18%) had a higher prevalence (P<0.01) of long duration of diabetes and PVD.

CONCLUSIONS

This is the first study which provides insights into the applicability and accuracy of ECG stress in screening SMI in high-risk patients with T2D. Due to the high prevalence of CAD, alternative screening tests in patients unable to perform the test and in those with a high chance of being 'false negative' should be looked for and validated.

Anomalous optical absorption in the normal state of overdoped cuprates near the charge-ordering instability

We argue that the hump observed in the optical conductivity at or below a few hundreds of cm(-1), in overdoped cuprates such as the electron-doped Nd(2-x)Ce(x)CuO(4-y) at x > or approximately equal to 0.15 and the hole-doped Bi2Sr2CuO6 and La2-xSrxCuO4, cannot be accounted for within a single-fluid description. We propose instead an interpretation based on the direct excitation of charge collective modes, which become nearly critical in the proximity to a charge-ordering instability. Their critical character entails a peculiar temperature dependence and a pseudoscaling form of the optical spectra, which agree with the experimental data.

First-order pairing transition and single-particle spectral function in the attractive hubbard model

A dynamical mean-field theory analysis of the attractive Hubbard model in the normal phase is carried out upon restricting to solutions where superconducting order is not allowed. A clear first-order pairing transition as a function of the coupling takes place at all the electron densities out of half filling between a Fermi liquid, stable for U<U(c), and an insulating bound pairs phase for U>U(c), and it is accompanied by phase separation. The spectral function in the metallic phase is constituted by a low-energy structure around the Fermi level, which disappears discontinuously at U = U(c), and two high-energy features (Hubbard bands), which persist in the insulating phase.

Anomalous isotopic effect near the charge-ordering quantum criticality

Within the Hubbard-Holstein model, we evaluate the crossover lines marking the opening of pseudogaps in the cuprates, which, in our scenario, are ruled by the proximity to a charge-ordering quantum criticality (stripe formation). We find that their isotopic dependence, due to critical fluctuations, implies a substantial positive shift of the pseudogap-formation temperature T(*). We infer that the isotopic shift of the superconducting T(c) is nearly absent in the optimally and overdoped regimes and is negative and increasing upon underdoping. The dynamical nature of the charge-ordering transition may explain the spread of the experimental values of T(*).

Early-onset amyloid deposition and cognitive deficits in transgenic mice expressing a double mutant form of amyloid precursor protein 695

We have created early-onset transgenic (Tg) models by exploiting the synergistic effects of familial Alzheimer's disease mutations on amyloid beta-peptide (Abeta) biogenesis. TgCRND8 mice encode a double mutant form of amyloid precursor protein 695 (KM670/671NL+V717F) under the control of the PrP gene promoter. Thioflavine S-positive Abeta amyloid deposits are present at 3 months, with dense-cored plaques and neuritic pathology evident from 5 months of age. TgCRND8 mice exhibit 3,200-4,600 pmol of Abeta42 per g brain at age 6 months, with an excess of Abeta42 over Abeta40. High level production of the pathogenic Abeta42 form of Abeta peptide was associated with an early impairment in TgCRND8 mice in acquisition and learning reversal in the reference memory version of the Morris water maze, present by 3 months of age. Notably, learning impairment in young mice was offset by immunization against Abeta42 (Janus, C., Pearson, J., McLaurin, J., Mathews, P. M., Jiang, Y., Schmidt, S. D., Chishti, M. A., Horne, P., Heslin, D., French, J., Mount, H. T. J., Nixon, R. A., Mercken, M., Bergeron, C., Fraser, P. E., St. George-Hyslop, P., and Westaway, D. (2000) Nature 408, 979-982). Amyloid deposition in TgCRND8 mice was enhanced by the expression of presenilin 1 transgenes including familial Alzheimer's disease mutations; for mice also expressing a M146L+L286V presenilin 1 transgene, amyloid deposits were apparent by 1 month of age. The Tg mice described here suggest a potential to investigate aspects of Alzheimer's disease pathogenesis, prophylaxis, and therapy within short time frames.

Induction of p53 in the glutamate-induced cell death program

Fifteen minute exposure of primary cultures of cerebellar granule cells to micromolar concentrations of glutamate results in apoptotic cell death. Among the intracellular events triggered by glutamate, we identified two transcriptional factors, i.e. the p50 member of the NF-kappaB family and the tumor suppressor phosphoprotein p53, that are apparently linked by a sequential trascriptional program. We found that pretreatment of the cultures with aspirin (ASA), which inhibits NF-kappaB activation, resulted in a complete prevention of glutamate-induced p53 immunoreactivity. The same results were obtained pretreating the cells with a specific p53 antisense oligonucleotide. Both ASA and p53 antisense abolished glutamate-induced apoptosis. We also found that two other proteins, the cyclin dependent kinase inhibitor p21 and DNA mismatches repair MSH2, whose encoding genes are well known target of p53, were upregulated by glutamate. On these bases, we propose NF-kappaB, p53, p21 and MSH2 as relevant contributors of the glutamate-induced pro-apoptotic pathway.

Presenilin-1 regulates the neuronal threshold to excitotoxicity both physiologically and pathologically

A direct pathophysiological role of Familial Alzheimer's Disease (FAD)-associated Presenilin 1 (PS1) mutations in neuronal vulnerability remains a controversial matter. We evaluated the relationship between PS1 and excitotoxicity in four different experimental models of neurotoxicity by using primary neurons from (i) transgenic (tg) mice overexpressing a human FAD-linked PS1 variant (L286V mutation), (ii) tg mice overexpressing human wild-type (wt) PS1, (iii) PS1 knockout mice, and (iv) wt mice in which PS1 gene expression was knocked down by antisense treatment. We found that primary neurons overexpressing mutated PS1 showed an increased vulnerability to both excitotoxic and hypoxic-hypoglycemic damage when compared with neurons obtained from either mice overexpressing human wt PS1 or in wt mice. In addition, reduced excitotoxic damage was obtained in neurons in which PS1 expression was absent or diminished. Data obtained in in vivo experimental models of excitotoxicity partially supported the in vitro observations. Accelerated neuronal death was demonstrated in the hippocampus of mice overexpressing mutated PS1 after peripheral administration of kainic acid in comparison with wt animals. However, measurement of the infarct volume after middle cerebral artery occlusion did not show significant difference between the two animal groups. The results altogether suggest that expression of FAD-linked PS1 variants increases the vulnerability of neurons to a specific type of damage in which excitotoxicity plays a relevant role. In addition, they support the view that reduction of endogenous PS1 expression results in neuroprotection.

Interleukin-10 modulates neuronal threshold of vulnerability to ischaemic damage

Interleukin-10 (IL-10) is a powerful suppressor of cellular immune responses, with a postulated role in brain inflammation. First, we have evaluated the role of this cytokine in ischaemic brain damage using IL-10 knockout (IL-10-/-) mice. The middle cerebral artery (MCA) was occluded in either IL-10-/- or wild-type animals of corresponding strain (C57Bl/6) and age. Infarct volume was assessed 24 h later in serial brain sections. Brain infarct produced by MCA occlusion was 30% larger in the IL-10-/- than in wild-type mice (21. 8 +/- 1.2 vs. 16.9 +/- 1.0 mm3, respectively; P < 0.01; Student's t-test). To further characterize these findings, studies were extended to in vitro models. Primary neuronal cortical cultures derived from IL-10-/- animals were more susceptible to both excitotoxicity and combined oxygen-glucose deprivation compared with cell cultures from wild-type mice. Moreover, when added to the culture medium, recombinant murine IL-10 (0.1-100 ng/mL) exerted a concentration-dependent prevention of neuronal damage induced by excitotoxicity in both cortical and cerebellar granule cell cultures taken from either strain. The accordance of in vivo and in vitro data allows us to suggest a potential neuroprotective role of IL-10 against cerebral ischaemia when administered exogenously or made available from endogenous sources.

Contribution of NF-kappaB and p53 in the glutamate-induced apoptosis

Exposure of primary cultures of cerebellar granule cells for 15 min to micromolar concentrations of glutamate results in cell death of both necrotic and apoptotic types. Among the intracellular events triggered by glutamate, we identified two transcriptional factors: the p50 member of the NF-kappaB family and the tumor suppressor phosphoprotein p53. Pretreatment of the cultures with aspirin, which inhibits NF-kappaB activation, or with specific p53 antisense oligonucleotide, which inhibits p53 transcription, resulted in a complete prevention of glutamate-induced p53 induction and apoptosis. These findings suggest the existence of a transcriptional program activated by glutamate receptor stimulation in which p50 and p53 play a relevant role. Then, we studied the expression of two p53 downstream genes that could participate in the glutamate-induced pro-apoptotic pathway: p21, which codes for an inhibitor of different cyclin dependent kinases, and MSH2, which codes for a protein involved in the recognition and repair of DNA mismatches. We found that primary cerebellar neurons expressed p21 and MSH2 at very low levels in basal conditions. However, very soon after a brief exposure of the cells to glutamate, the expression of both proteins was dramatically enhanced.On these bases, we propose NF-kappaB, p53, p21 and MSH2 as relevant contributors of the glutamate-induced pro-apoptotic pathway. Understanding this cascade of nuclear events may unravel specific targets for pharmacological intervention for those neurological diseases in which excitatory amino acid-induced apoptosis plays a relevant role.

Stripe formation in electron-doped cuprates

We investigate the formation of charge domain walls in an electron-doped extended Hubbard model for the superconducting cuprates. Within an unrestricted Hartree-Fock approach, extended by slave bosons to obtain a better treatment of strong correlations, we demonstrate the occurrence of stripes in the (1,1) and (1,-1) directions having one doped electron per stripe site. The different filling, direction, and width of these electron-doped stripes with respect to those obtained in the hole-doped systems have interesting observable consequences.

Possible role of NF-kappaB and p53 in the glutamate-induced pro-apoptotic neuronal pathway

Apoptosis is now recognized as an important component in many progressive and acute neurodegenerative diseases. Extracellular signals and intracellular mechanisms triggering and regulating apoptosis in neuronal cells are still a matter of investigation. Here we review data from our and other laboratories with the aim to elucidate the nature of some proteins which are known to be involved in cell cycle regulation as well as in promoting degeneration and apoptosis of neurons. The following molecules will be taken into consideration: NF-kappaB, p53, p21 and MSH2. These proteins are activated by neurotoxic experimental conditions which involve the stimulation of selective receptors for the excitatory aminoacid glutamate. Thus, we hypothesize their contribution to an intracellular pathway responsible for the glutamate-induced neuronal death. Identification of such mechanisms could be relevant for understanding the apoptosis associated with various neurodegenerative diseases as well as for developing novel strategies of pharmacological intervention.

Nuclear factor-kappaB/Rel proteins: a point of convergence of signalling pathways relevant in neuronal function and dysfunction

Nuclear factor-kappaB (NF-kappaB)/Rel designates a family of transcription factors participating in the activation of a wide range of genes crucially involved in immune and inflammatory function. NF-kappaB/Rel proteins have been demonstrated recently in primary neurons and in several brain areas. Functional significance of these proteins is still not understood completely, but since certain subsets of neurons appear to contain constitutively active DNA-binding activity, it seems likely that they may participate in normal brain function. A growing body of evidence is accumulating for a specific activation of NF-kappaB/Rel proteins in the CNS, and in particular in neuronal cells, during neurodegenerative processes associated to etiologically unrelated conditions. Whether NF-kappaB activation is part of the neurodegenerative process or of protective mechanisms is a matter of debate. This issue will be reviewed here with particular attention to the available reports on the activity of NF-kappaB/Rel proteins in both experimental paradigms of neurodegeneration and post-mortem brain tissue of patients affected by various neurological diseases. We hypothesize that NF-kappaB/Rel proteins may represent the point of convergence of several signalling pathways relevant for initiating or accelerating the process of neuronal dysfunction and degeneration in many neurological diseases, including Parkinson's disease, Alzheimer's disease, CNS viral infections, and possibly others. If NF-kappaB/Rel proteins represent an integrating point of several pathways potentially contributing to neuronal degeneration, molecules that finely modulate their activity could represent a novel pharmacological approach to several neurological diseases.

Metoclopramide and domperidone block the antihypertensive effect of bromocriptine in hypertensive patients

This study was conducted in normotensive and hypertensive subjects at the Vargas Hospital of Caracas. Normotensive subjects received, in a cross-over fashion, placebo, metoclopramide (MTC), or domperidone (DOMP), 40 mg of each drug, daily for 1 week. The first group of patients under placebo for 1 week received a single 2.5-mg oral dose of bromocriptine (Br). The second group of patients received 30 mg MTC daily (divided into three doses) for 1 week. At the end of the period a single dose of 2.5 mg Br was administered to each patient. The third group of eight hypertensive patients received DOMP for 1 week at 30 mg/d and then a single 2.5-mg Br dose. Cardiovascular and biochemical parameters including arterial pressure, heart rate, plasma renin activity, and plasma aldosterone were evaluated during the 6-hour period before and after the administration of Br. Neither DOMP nor MTC significantly modified blood pressure and heart rate in normotensive patients. Br reduced both systolic and diastolic arterial pressure in hypertensive subjects. The peak of the antihypertensive effect appeared 3 hours after drug administration, but reduction of arterial pressure lasted approximately 6 hours. At the same time, Br reduced plasma aldosterone levels and plasma renin activity. MTC and DOMP reversed the antihypertensive effect of Br and its effect on aldosterone levels and plasma renin activity. We conclude from these findings that Br acts as an antihypertensive agent at peripheral and central levels by stimulating dopamine-2 receptors, which are involved in the aldosterone and renin secretion.

Induction of tumour-suppressor phosphoprotein p53 in the apoptosis of cultured rat cerebellar neurones triggered by excitatory amino acids

We found that primary cultures of rat cerebellar granule cells, although definitely postmitotic and terminally differentiated, express the tumour-suppressor phosphoprotein p53. In particular, granule cells both expressed significant levels of p53 mRNA and positively reacted to an anti-p53 antibody, from the first day of culturing. During neurone differentiation, p53 mRNA content did not significantly change, at least up to 12 days in vitro, while p53 immunoreactivity increased gradually. p53 expression appeared to be further modulable being upregulated after stimulation of glutamate ionotropic receptors by glutamate or kainate. Although qualitatively similar, p53 induction by glutamate and kainate differed in terms of intensity and time-course. The glutamate increase of p53 immunoreactivity appeared within 30 min after the treatment and lasted for at least 2 h. Kainate-induced increase of p53 immunoreactivity was delayed, becoming apparent within 2 h and lasting for at least 8 h. Both kainate- and glutamate-induced increases of p53 immunoreactivity were prevented by the non-competitive NMDA receptor antagonist MK 801. As shown by the electrophoretic mobility shift analysis, both glutamate and kainate induced increases of p53 DNA binding activity. Blockade of p53 induction by a specific p53 antisense oligonucleotide resulted in a partial reduction of excitotoxicity with a complete inhibition of the excitatory amino acids induced apoptosis. Our data suggest that stimulation of ionotropic glutamate receptors in neurones results in a p53-dependent apoptosis.

Priming of cultured neurons with sabeluzole results in long-lasting inhibition of neurotoxin-induced tau expression and cell death

Sabeluzole was described to have antiischemic, antiepileptic, and cognitive-enhancing properties, and is currently under development for Alzheimer's disease. Recently, it was reported that repeated treatments with sabeluzole protect cultured rat hippocampal neurons against NMDA- and glutamate-induced neurotoxicity. We evaluated the possibility that sabeluzole elicits neuroprotection by acting, either directly or indirectly, on tau proteins. We found that repeated treatments during development of primary cultures of cerebellar granule cells with nanomolar concentrations of sabeluzole resulted in mature cells that were resistant to the excitotoxicity induced by glutamate. Also, sabeluzole treatment specifically prevented the glutamate-induced increase of tau expression without modifying the basal pattern of expression of tau proteins, as shown by measurement of mRNA and protein levels. In human neuroblastoma cell line SH-SY5Y, differentiated by treatment with retinoic acid, doxorubicin increased tau immunoreactivity, and later induced cell death. Both effects were prevented by sabeluzole. Our data indicate that increased tau expression is a common response to different types of cells to neurotoxic agents, and that sabeluzole-induced neuroprotection is functionally associated with the prevention of the injury-mediated increase of tau expression.

Regulation of mouse neuropeptide Y Y1 receptor gene transcription: a potential role for nuclear factor-kappa B/Rel proteins

We previously isolated a 1.3-kb genomic fragment in the 5'-flanking region of the murine neuropeptide Y (NPY) Y1 receptor gene, which is able to drive the expression of LacZ reporter gene in neuronal cells. We determined the ability of deletion mutants of this region to modulate transcription of the heterologous luciferase gene in the Y1 receptor-expressing neuroblastoma/ glioma NG108-15 cells and the Y1 receptor-deficient 293 cells. Results suggest the presence of a cell type-specific core promoter (-399 to -218 from the initiator ATG) and, upstream, of two positive and two negative regulatory elements. Sequence analysis of the Y1 receptor promoter identified two decameric sequences corresponding to consensus binding sites for nuclear factor-kappa B/Rel proteins. Gel shift analysis indicated that a 29-bp oligonucleotide comprising the two putative kappa B sites, which we refer to as Y1-kappa B sequence, specifically binds kappa B-related complexes in nuclear extracts from rat brain areas, NG108-15 cells, and the murine T cell clone A.E7. In nuclear extracts from A.E7 and NG108-15 cells, the Y1-kappa B sequence specifically binds an additional complex whose molecular nature remains to be elucidated. Through transient transfection studies, we also demonstrated that the Y1-kappa B sequence acts as an enhancer element, inferring its potential role in regulation of the Y1 receptor gene expression.

Neuroprotection by aspirin and sodium salicylate through blockade of NF-kappaB activation

Aspirin (acetylsalicylic acid) is a commonly prescribed drug with a wide pharmacological spectrum. At concentrations compatible with amounts in plasma during chronic anti-inflammatory therapy, acetylsalicylic acid and its metabolite sodium salicylate were found to be protective against neurotoxicity elicited by the excitatory amino acid glutamate in rat primary neuronal cultures and hippocampal slices. The site of action of the drugs appeared to be downstream of glutamate receptors and to involve specific inhibition of glutamate-mediated induction of nuclear factor kappa B. These results may contribute to the emerging theme of anti-inflammatory drugs and neurodegeneration.

Interleukin-1beta and glutamate activate the NF-kappaB/Rel binding site from the regulatory region of the amyloid precursor protein gene in primary neuronal cultures

We originally reported that members of the family of transcription factors NF-kappaB/Rel can specifically recognize two identical sequences, referred to as APPkappaB sites, which are present in the 5'-regulatory region of the APP gene. Here we show that the APPkappaB sites interact specifically with a complex which contains one of the subunits of the family, defined as p50 protein, and that they act as positive modulators of gene transcription in cells of neural origin. Additionally, the nuclear complex specifically binding to the APPkappaB sites is constitutively expressed in primary neurons from rat cerebellum and it is up-regulated in response to both the inflammatory cytokine interleukin-1beta (IL-1beta) and the excitatory amino acid glutamate. Since IL-1, whose levels are known to be induced in brain of individuals affected by Alzheimer's disease, and glutamate, are stimuli which have been regarded as major actors on the stage of neurodegenerative processes, we believe our evidence as potentially relevant for understanding the neuropathology associated with Alzheimer's disease.

Plasma lipoprotein(a) levels in subjects attending a metabolic ward. Discrimination between individuals with and without a history of ischemic stroke

In this cross-sectional study we compared the abilities of lipoprotein(a) [Lp(a)], plasminogen activator inhibitor-1 (PAI-1), and tissue plasminogen activator (TPA) to discriminate between individuals with and without a history of stroke from among subjects in a metabolic ward. A total of 210 subjects (108 men and 102 women; mean age, 63.8 years; range, 31 to 86 years) provided plasma and DNA samples for the study. Of these, 51 men and 50 women had a history of ischemic stroke. The 109 subjects without a history of stroke were compared with those with such a history for major risk factors for ischemic events. Mean plasma TPA and PAI-1 levels significantly (P < .001) discriminated among subjects younger than 70 years with a history of stroke. The mean plasma Lp(a) level of stroke subjects (21.9 mg/dL) did not differ significantly from that of control subjects (15.2 mg/dL). However, among individuals < 70 years old, Lp(a) plasma levels > 50 mg/dL were more common among stroke patients (8 with versus 1 without, P < .01 by chi 2 test). A molecular variation in the 5' flanking region of the apo(a) gene that has been related to elevated Lp(a) plasma levels (G/A-914) was not strongly correlated with circulating levels of Lp(a), nor did Lp(a) levels correlate with a polymorphism of the apo(a) gene (G/A-21), which is strongly linked (P < .001) to the G/A-914 variation. In this setting, the relation between Lp(a) and cerebral ischemia appears to be limited to individuals below 70 years with elevated (> 50 mg/dL) plasma levels of the lipoprotein.

Identification and characterization of a kappa B/Rel binding site in the regulatory region of the amyloid precursor protein gene

Several observations support the hypothesis that pathogenetic mechanisms of beta amyloid formation in Alzheimer's disease may involve alterations in amyloid precursor protein (APP) gene expression. In this regard, molecular dissection of the APP gene transcriptional regulation is of primary importance. We report evidence that members of the family of transcription factors NF kappa B/Rel can specifically recognize two identical sequences located in the 5'-regulatory region of APP. These sequences, which we refer to as APP kappa B sites, interact preferentially with p50-containing members of the family. In particular, p50 homodimers and p50/p65 and p50/c-Rel heterodimers act as transcriptional activators at the APP kappa B site. Finally, the nuclear complex specifically binding to the APP kappa B sites proves to be an integral part of neurons and lymphocytes.

Metoclopramide blocks bromocriptine induced antihypertensive effect in hypertensive patients

Two groups of patients with essential hypertension were studied at the Vargas Hospital of Caracas. The first group of 9 patients under placebo treatment for 1 week received a single 2.5 mg oral dose of bromocriptine. Cardiovascular and biochemical parameters including arterial pressure, heart rate, plasma renin activity, and plasma aldosterone levels were evaluated during the 6-hour period before and after the administration of drugs. The second experimental design was as follows: 9 patients received 30 mg metoclopramide daily (divided in 3 doses) for 1 week. At the end of the period a single oral dose of 2.5 mg of bromocriptine was given to each patient. The cardiovascular and biochemical parameters were also determined. Bromocriptine reduced both systolic and diastolic arterial pressure. The peak antihypertensive effect was shown 3 hours after administration of the drug, but the reduction of arterial pressure lasted approximately 6 hours. At the same time bromocriptine reduced plasma aldosterone levels and plasma renin activity. This reduction persisted 6 hours after its administration. Metoclopramide reversed the antihypertensive effect of bromocriptine and its effect on aldosterone secretion and plasma renin activity. We conclude from these findings that bromocriptine acts as an antihypertensive agent by stimulating DA2 dopaminergic receptor, the dopaminergic receptor involved in aldosterone and renin secretion is possibly DA2.

Opposing regulation of amyloid precursor protein by ionotropic and metabotropic glutamate receptors

The effects of the ionotropic glutamate receptor (iGluR) selective agonist N-methyl-D-aspartate (NMDA) on amyloid precursor protein (APP) levels were investigated in primary cultures of rat cerebellar granule cells. Both immunocytochemistry and immunoblotting techniques showed increased APP levels 4 h after a 15 min pulse with NMDA. This effect was completely prevented by incubating the neurones in the presence of the selective metabotropic GluR (mGluR) agonist 1S,3R-ACPD. This phenomenon was related, in terms of doses and time, with the observed 1S,3R-ACPD-mediated protection on NMDA-induced granule cell death. Our findings indicate that APP metabolism is differentially regulated by the stimulation of various GluR subtypes. The GluR-mediated changes in APP content might participate in the control of neuronal viability.

Raised plasma fibrinogen concentrations in subjects attending a metabolic ward--relation to family history and vascular risk factors

We have evaluated plasma fibrinogen levels in 171 subjects attending a metabolic ward. As in the general population, a significant difference in plasma fibrinogen concentrations (p < 0.05) was found between subjects with diabetes mellitus or hypertension and those without. However, fibrinogen was also abnormally high (p < 0.05) when evaluated according to the presence of a family history of ischemic complications of atherosclerosis (p < 0.05). In this setting, fibrinogen correlated with diabetes mellitus or hypertension as well as with familial risk, and the latter interacted with hypertension (p < 0.05) in accounting for plasma fibrinogen. The relationships between certain fibrinogen genotypes and familial risk have then been evaluated. Analysis of a locus (1.3 kb, HAE III digestion) of the promoter region of the B beta fibrinogen gene, identified a polymorphic cutting site. The allele with the alternative restriction site (H1) was associated with mean fibrinogen levels which were 0.1-0.3 g/l lower than those associated with the other allele (H2). This difference was not statistically significant. No obvious association was found between the familial risk and the presence of the H2 allele. We conclude that in a group of subjects from a metabolic ward, a positive family history for ischemic complications of atherosclerosis is consistently associated with high plasma fibrinogen levels. Interaction with hypertension significantly strengthens the association.

Abnormally high circulation levels of tissue plasminogen activator and plasminogen activator inhibitor-1 in patients with a history of ischemic stroke

We evaluated 106 subjects with and 109 subjects without a history of ischemic stroke. All were attending a metabolic ward. The two groups were compared for major risk factors for ischemic events. A positive family history for ischemic complications of atherosclerosis was more common in subjects with a history of stroke than in those without; moreover, plasma levels of plasminogen activator inhibitor-1 (PAI-1) and tissue-type plasminogen activator (TPA) were higher in patients with documented previous events. A strong positive significant correlation was found between TPA and PAI-1 levels, and an interaction between age and TPA was observed when the sample was stratified according to ages being above or below 70 years. When the patient population was analyzed according to the number of ischemic events, it was found that 62 of the 106 subjects with a history of stroke had experienced more than one ischemic event. Under these conditions, the levels of TPA and PAI-1 still correlated with the occurrence of previous ischemic episodes. As in the whole patient sample, TPA was the strongest discriminator. We conclude that in subjects attending a metabolic ward, TPA and PAI-1 levels consistently help identify subjects with a history of cerebral ischemic episodes and that TPA is the strongest discriminator.

[Acute viral myocarditis with transient concentric pseudohypertrophy of the left ventricle complicated by cardiogenic shock]

The authors report the case of a 38-year-old woman with acute influenza myocarditis, cardiogenic shock and multiorgan injuries. The echocardiogram showed symmetric thickening and severe hypokinesis of the ventricular wall, with a concomitant reduction of the left ventricular cavity due to myocardial edema and cellular infiltration. The myocardial thickening gradually decreased and the ejection fraction improved, as shown by serial echocardiographic evaluations. Blood levels of cardiospecific enzymes were slightly elevated and ECG showed little change. The myocarditis resolved without sequelae. The hemodynamic implications of this transient myocardial thickening and its relationship to steroid therapy are discussed.

Tumor necrosis factor alpha mediates a T cell receptor-independent induction of the gene regulatory factor NF-kappa B in T lymphocytes

We investigated the molecular basis of the ability of DCEK experimental antigen-presenting cells (APCs) to induce the nuclear form of the transcription factor NF-kappa B in T lymphocytes without engagement of the T cell receptor. We found that NF-kappa B induction did not require contact between the APCs and T lymphocytes and could be achieved by medium conditioned by the APCs. The APCs were found to express low levels of mRNA for TNF alpha. The addition of antibody against TNF alpha blocked the ability of APCs to induce NF-kappa B. These observations were extended by the finding that NF-kappa B was also induced in T lymphocytes separated by a membrane from a mixture of T lymphocytes, splenic APCs and antigen by a TNF alpha-dependent mechanism. Together, these findings suggest that induction of NF-kappa B in antigenically stimulated or 'bystander' T cells may take place through stimulation by TNF alpha as well as in response to T cell receptor occupancy.

NF-kappa B subunit regulation in nontransformed CD4+ T lymphocytes

Regulation of interleukin-2 (IL-2) gene expression by the p50 and p65 subunits of the DNA binding protein NF-kappa B was studied in nontransformed CD4+ T lymphocyte clones. A homodimeric complex of the NF-kappa B p50 subunit was found in resting T cells. The amount of p50-p50 complex decreased after full antigenic stimulation, whereas the amount of the NF-kappa B p50-p65 heterodimer was increased. Increased expression of the IL-2 gene and activity of the IL-2 kappa B DNA binding site correlated with a decrease in the p50-p50 complex. Overexpression of p50 repressed IL-2 promoter expression. The switch from p50-p50 to p50-p65 complexes depended on a protein that caused sequestration of the p50-p50 complex in the nucleus.