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Biomedical subjects

F Galli

Publications and source records attributed to F Galli.

At least 37 records · Page 2Linked to original sources
PubMed2000

Charge-density-wave transitions in the local-moment magnet Er5Ir4Si10

We report the observation of a new type of charge-density wave (CDW) in the large magnetic-moment rare-earth intermetallic compound, Er5Ir4Si10, which then orders magnetically at low temperatures. Single crystal x-ray diffraction shows the development of a 1D incommensurate CDW at 155 K, which then locks into a purely commensurate state below 55 K. The well-localized Er3+ moments are antiferromagnetically ordered below 2.8 K. We observe very sharp anomalies in the specific heat at 145 and 2.8 K, signifying the bulk nature of these transitions. Our data suggest the coexistence of strongly coupled CDW with local-moment antiferromagnetism in Er5Ir4Si10.

Journal Article↗
PubMed2000

H2O2-induced block of glycolysis as an active ADP-ribosylation reaction protecting cells from apoptosis.

H2O2 treatment on U937 cells leads to the block of glycolytic flux and the inactivation of glyceraldehyde-3-phosphate-dehydrogenase by a posttranslational modification (possibly ADP-ribosylation). Glycolysis spontaneously reactivates after 2 h of recovery from oxidative stress; thereafter cells begin to undergo apoptosis. The specific ADP-ribosylation inhibitor 3-aminobenzamide inhibits the stress-induced inactivation of glyceraldehyde-3-phosphate-dehydrogenase and the block of glycolysis; concomitantly, it anticipates and increases apoptosis. Exogenous block of glycolysis (i.e., by culture in glucose-free medium or with glucose analogs or after NAD depletion), turns the transient block into a stable one: this results in protection from apoptosis, even when downstream cell metabolism is kept active by the addition of pyruvate. All this evidence indicates that the stress-induced block of glycolysis is not the result of a passive oxidative damage, but rather an active cell reaction programmed via ADP-ribosylation for cell self-defense.

Apoptosis↗
PubMed2000

"From 0 to 18": what happens to the child and his headache?

Prospective and retrospective studies showed that headaches (migraine and tension-type) with childhood or adolescent onset have age-related characteristics and change over time, with high rate of type changing, remission or improvement. The reasons are unknown. On the other hand, several studies focused on factors that may be precursors of childhood headaches. All these factors may allow a developmental arc to be outlined, defining the natural history of headache from birth to adulthood. Familial (genetic?) influence, hyperreactivity, periodic syndromes and anxiety in childhood are factors that may predict headache onset, against the background of developmental modulation of pain. Biological and psychological factors are probably reciprocally involved, although the link is unclear. The identification of prognostic factors could allow a better framing of headaches and, from an integrated perspective, have important implications as regards clarifying the "nature" of headache.

Adolescent↗
PubMed1999

Biological effects of oxidant stress in haemodialysis: the possible roles of vitamin E.

Oxidative stress has been proposed to play a role in many disease states, including cardiovascular and infectious diseases, cancer, diabetes and neurodegenerative pathologies. The fact that these diseases have an increased incidence in uremia, and particularly in dialysis patients, suggests an increased exposure to oxidative stress in this condition. In haemodialysis (HD), the absence of a complete correction of the uremic toxicity together with the untoward effects of the dialysis, malnutrition and the progressive worsening of the clinical condition, can lead to a high susceptibility to oxidative stress by an abnormal production of oxidants - including reactive oxygen species (ROS) and uremic toxins with prooxidant function - and defective antioxidant protection. One of the most investigated biological effects of the oxidative stress in the HD patients is lipid peroxidation in plasma and blood cell membranes. Moreover, we have recently described how abnormal apoptosis in peripheral blood leukocytes is associated with cell oxidative stress (intracellular thiol depletion). Vitamin E, in both in vitro and in vivo conditions, has been proposed to partially correct these effects. In this review we evaluated some features of two new dialysis strategies using an antioxidant approach to the protection against the oxidant stress in HD. Their rationale is based on the emerging role of vitamin E in counteracting some biological effects associated with oxidant stress namely lipid peroxidation and apoptosis. These techniques use: 1) the recirculation of the dialysate through a suspension of vitamin E-enriched liposomes combined with the supplementation by the dialysate with ascorbic acid, this method has been called hemolipodialysis; 2) the coating of the dialysis membrane with vitamin E (vitamin E- modified dialysis membranes). These unconventional approaches to the antioxidant therapy in HD open a widely unexplored and promising field in the evolution of the biomaterials and dialysis quality.

Animals↗
PubMed1999

Sleep hygiene and migraine in children and adolescents.

Although sleep problems are a common complaint in migraine patients, the role of sleep habits and hygiene as triggering factors of head pain attacks has been poorly analyzed. The aim of this study was to evaluate the effect of modifying bad sleep habits across several headache parameters. Based on our previous study, we selected 70/164 migraineurs (42.7%) with poor sleep hygiene and randomly assigned them to two groups: group A migraineurs, who were instructed to follow directions to improve sleep hygiene; and group B migraineurs who were not given instructions on improving sleep hygiene. Mean duration and frequency of migraine attacks were significantly reduced at follow-up in group A, while group B showed only an insignificant initial reduction. No differences were found in the severity of migraine attacks that seemed related to a higher prevalence of nocturnal symptoms such as bedtime struggles, hypnic jerks, nightmares, and restless sleep. Our study is an alternative approach to the treatment of migraine, i.e. treatment through a simple modification of sleep behavior without recurring to pharmacological treatment.

Adolescent↗
PubMed1999

Overexpression of erythrocyte glutathione S-transferase in uremia and dialysis.

BACKGROUND: Overexpression of glutathione S-transferase (GST; EC 2.5. 1.18) has been documented in the erythrocytes of patients with chronic renal failure, and this event may well be of relevance from a clinical standpoint. In fact, it could serve as a marker of uremic toxicity overall, which can contribute to impair the function and survival of the erythrocytes. However, the biochemical details of this phenomenon are poorly understood. METHODS: In this study, we characterized the expression of GST in erythrocytes of 118 uremic patients under different clinical conditions. The mechanisms responsible for the regulation of protein expression and enzyme activity were investigated in light of different dialysis approaches, oxidative stress, uremic toxins, erythrocyte age, and erythropoietin (EPO) supplementation. RESULTS: Mean GST activity in uremic patients was highly overexpressed with respect to controls, and this phenomenon was exclusively attributable to an increased expression of GST. Overexpression of GST did not appear to be dependent on oxidative stress and was not influenced by vitamin E supplementation. In the same manner, both erythrocyte age and EPO supplementation apparently did not interfere with the GST concentrations, which were the same in controls and patients. Preliminary experiments suggested that high-molecular weight or protein-bound toxins could play some role in the overexpression of GST. CONCLUSIONS: GST expression may be a useful marker for the individual accumulation of uremic toxins as well as of the efficiency of new dialysis strategies in removing them.

Biomarkers↗
PubMed1998

S-nitrosylation of glyceraldehyde-3-phosphate dehydrogenase decreases the enzyme affinity to the erythrocyte membrane.

The effects of nitric oxide (NO) or related molecules on the binding of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to the red blood cell (RBC) membrane were investigated. It was demonstrated that submillimolar concentrations of the NO donor sodium nitroprusside (SNP) not only strongly inactivated GAPDH by S-nitrosylation of the enzyme thiols but also decreased the binding affinity of GAPDH for the RBC membrane. In fact, the incubation with SNP for 60 min at 30 degrees C and at a concentration > 50 microM induced the dissociation of the native GAPDH from the white unsealed membranes (standard ghosts) in a concentration-dependent manner with a partial recovery of the enzyme activity and thiols when SNP concentrations higher of 1 mM were used. Binding experiments under saturating conditions indicate a Ka value for the nitrosylated GAPDH of 3.5 +/- 0.8 x 10(6) M-1, which was more than 50% less than the Ka value of 7.6 +/- 0.6 x 10(6) M-1 observed for the native enzyme. These data were also confirmed in reassociation experiments under nonsaturating conditions. Dithiothreitol (DTT), which at concentrations of less than 1 mM catalyzed the S-nitrosylation of GAPDH and the consequent modification of the binding properties described above, the concentrations higher than 5 mM restored both the enzyme activity and the binding properties. Furthermore, the enzyme-membrane association induced before the incubation step afforded at least partial protection from the loss of titrable thiols and from the inactivation induced either spontaneously or by SNP. Taken together, these data not only confirm the key role of the active site cysteine residues in the catalytic function of GAPDH but also suggest that they may be involved in the NO-dependent regulation of GAPDH binding to the RBC membrane.

Animals↗
PubMed1998

Evolution of headache in childhood and adolescence: an 8-year follow-up.

OBJECTIVE: Headache is a notable problem in clinical practice and a frequent symptom in childhood and adolescence. The main aim of the present study is to analyze the evolution of migraine and tension headache (TH) using an 8-year follow-up. METHOD: 100 subjects (F60, M40; mean age 17.9; SD 2.6; range 12-26), randomly selected among all patients first seen in 1988 at the Headache Center, were directly contacted. We employed IHS criteria both in 1988 (the data were taken by the clinical charts) and 1996. We took into account changes in headache types and improvement, unchanging, worsening or remission of headache. This analysis was made with regard to gender differences and age at onset of headache, too. The chi-squared test is employed. FINDINGS: High tendency to remit (34%) or improve (45%) was recorded. A worsening situation was seen in 6% and an unchanging situation in 15%. In 1988, we had 57% migraine without aura (MwoA), 7% migraine with aura, 28% episodic tension-type headache (ETTH), and 8% chronic TH (CTTH). In 1996, we saw 30% MwoA, 2% MwA, 31% ETTH, and 3% CTH. Migraine shows a lower tendency to remit than TH (28.1% vs 44.4%). MwoA persists in the same form in 43.8% and becomes ETH in 26.3%. ETTH persists in the same form in 26.3% and changes in MwoA in 10.7%. Of headache-free subjects, we recorded a high tendency to remit (34%) and improve (95%); 13 were females (21.7%) and 21 were males (52.5%). The course of headache is not related to age at onset. CONCLUSION: Headache with juvenile onset changes its characteristics over time, with a high tendency to remit (mostly in males) or improve. The implications for pathophysiology and the role of hormonal factors are called into question.

Adolescent↗
PubMed1998

Headache and psychiatric comorbidity: clinical aspects and outcome in an 8-year follow-up study.

UNLABELLED: Migraine with juvenile onset changes over time. The existence of prognostic factors is a point of focus. A strict relationship between migraine or tension-type headache (TTH) and psychiatric factors has been suggested, but the exact role and the influence on evolution of headache is unknown. OBJECTIVE: To analyze the evolution of migraine and TTH and psychiatric comorbidity (P-Co) from 1988 to 1996. MATERIAL AND METHOD: 100 subjects (40M, 60F; mean age 17.9 years; SD 2.7 years; range 12-26 years) were examined at our Center. The International Headache Society (IHS) criteria were employed. Psychometric tests and clinical interviews aided psychiatric diagnosis (DSM-III-R). SCID (Structured Clinical Interview for DSM-III-R) was employed in 1996. Chi square and logistic regression are used for statistical analysis. FINDINGS: Migraine and TTH change their clinical characteristics, with a high tendency to remission (mostly in males). The presence of P-Co in 1988 is related to a worsening or unchanging situation in 1996. Headache-free subjects did not present any psychiatric disorders in 1996. Anxiety disorders in 1988 are related to enduring of headache. Migraine shows comorbidity with anxiety disorders and depression. CONCLUSION: P-Co is a notable problem in clinical practice. Diagnostic, prognostic, and treatment implications require a systematic assessment of P-Co.

Adolescent↗
PubMed1998

Bioreactivity and biocompatibility of a vitamin E-modified multi-layer hemodialysis filter.

BACKGROUND: The present study was designed to test the biocompatibility of a new vitamin E-modified multi-layer membrane (CL-E filter), as well as its ability to protect against oxygen free radicals during hemodialysis (HD). METHODS: We investigated, both in vitro and in vivo, the bioreactivity of the filter with respect to the blood antioxidants and its ability to prevent lipoperoxidation. The effects on the leukocyte respiratory burst were also studied. Cuprammonium rayon was used as a comparison material (CL-S filter). RESULTS: The in vitro results demonstrated that, under controlled conditions, CL-E is able to preserve blood antioxidants, and particularly vitamin E, from the spontaneous consumption observed in the incubation with CL-S filters and in control incubations. In accordance with this observation, the rate of the oxidative demolition of lipids either in plasma and red blood cells (RBC) or from rat brain homogenate decreased after the exposure to CL-E filters in comparison with the CL-S filter. Moreover, in the absence of any significant cytotoxic effects due to both the types of material studied, the production of oxygen free radicals and nitric oxide (NO) by leukocytes was higher after their in vitro exposure to CL-S, but was quite similar to that of the control leukocytes after exposure to CL-E. In vivo, a one-month treatment with the CL-E filter increased plasma vitamin E by 84.3% with respect to treatment with CL-S; this gain slightly decreased to 68.9% when CL-E treatment was prolonged to three months. In the RBC, vitamin E was found to have increased by 76.7% and 113.4% at one and three months, respectively. Plasma glutathione (GSH) levels determined at three months were significantly increased from 0.10 +/- 0.02 to 0.33 +/- 0.12 mumol/ml, while the erythrocyte GSH was only slightly increased. The leukocyte function estimated as responsiveness to soluble chemical stimuli in CL-S-treated patients was significantly improved both qualitatively and quantitatively after CL-E treatment. The presence of an increased number of mononuclear cells undergoing programmed cell death (apoptosis) in CL-S-treated patients (18.8 +/- 1.7% vs. a control value of 6.5 +/- 2.3%) as well as the apoptogenic effect of their plasma in vitro on U937 cells was significantly corrected after CL-E treatment (mean decrease in apoptotic mononuclear cells at 24 hours of culture, 25.5% and 27.1% at 1 and 3 months, respectively). The anti-apoptogenic effect of CL-E treatment showed a close dependence on the increase in vitamin E in the blood cell compartment. CONCLUSIONS: This study suggests that this vitamin E-modified membrane can be considered a highly biocompatible material, the antioxidant properties of which can exert a site-specific and timely scavenging function against oxygen free radicals in synergy with a hypostimulatory action on the PMN respiratory burst.

Aged↗
PubMed1998

Dialysis hypersensitivity: a fading problem?

Allergic-type reactions experienced by patients on chronic hemodialysis are frequently reported in the literature, often related to compounds released during the hemodialysis sessions, in particular ethylene oxide (ETO). In these studies, dialysis patients seem to have higher values of IgE than those observed in a reference population. The aim of our work was to investigate IgE-related parameters of 126 dialysis patients in comparison with two control groups composed of healthy subjects and predialysis patients. IgE values were not significantly different in nonallergic dialysis patients, with a geometric mean (X) of 27.5 kU/l, when compared to healthy controls (X = 38 kU/l) and predialysis subjects (X = 40.7 kU/l). Higher values of IgE (X = 74.1 kU/l) were detected in allergic dialysis patients. However, only 3 patients, all without detectable antibodies against ETO, complained of anaphylactic symptoms during dialysis sessions in a 4-year surveillance period. At variance, 6 symptom-free patients carried IgE antibodies against ETO (range 0.7-15 kU/l), usually with high total IgE. Our results suggest a reduced frequency of hypersensitivity reactions during dialysis sessions. Furthermore, uremia does not alter IgE reactivity in the predialysis period or after long-term maintenance dialysis treatment.

Adult↗