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Biomedical subjects

M Palestini

Publications and source records attributed to M Palestini.

At least 19 recordsLinked to original sources
PubMed2005

Interference of chronically ingested copper in long-term potentiation (LTP) of rat hippocampus.

The objective of our study was to find the evidence of copper interaction in LTP, motivated by copper involvement in neurodegenerative illness, like Parkinson, Alzheimer and Amyotrophic Lateral Sclerosis, and we initiated the study of this element in the LTP. For this purpose we used hippocampus slices of rats chronically consuming copper dissolved in water (CuDR; n=26) and non-copper-consuming rats (CR; n=20). The CuDR rats received 8--10 mg/day during 20--25 days. Electrophysiological tests showed absence of LTP in CuDR slices, contrary to CR slices. The stimulus-response test applied before and after LTP showed significant increases of synaptic potential in the CR group. This did not occur in the CuDR group, except for the initial values, which probably seem associated to an early action of copper. The paired-pulse (PP) test, applied to CR and CuDR prior to tetanic stimulation, showed a significant reduction in PP, for the 20-, 30- and 50-ms intervals in CuDR. At the end of the experiments, copper concentration was 54.2 times higher in CuDR slices, compared to the concentration present in CR slices. Our results show that copper reduces synaptic sensibility and also the facilitation capability. These effects represent a significant disturbance in the plasticity phenomenon associated with learning and memory.

Animals↗
PubMed2003

Copper interaction on the long-term potentiation.

The role of copper on the CA1 piramidal neurons and their sinaptic connections to the Schaffer's collateral was investigated using the field excitatory post-sinaptic potential (fEPSP). The same fEPSP was used to study copper effects on Long-term potentiation (LTP). We have found that copper 10 microM has an inhibitory action on the fEPSP. Similar effects were demonstrated with 10 microM of GABA. Moreover, copper showed a strong inhibitory action on the consolidated LTP. However, copper washout left a significant and persistent excitatory response. In our opinion, copper shows a dual sinaptic effect depending on the sinaptic experience.

Animals↗
PubMed2000

Copper sensitivity in dorsal hippocampus slices.

The action of copper on the pyramidal neurons in CA1 of the hippocampus is little understood. Our main aim was to study the possible interaction of copper on the synaptic network in CA1 pyramidal neurons. We used Wistar rats hippocampus slices in a recording chamber. The population response ("population of spikes") collected by an extracellular micropipette under baseline conditions served as control. Copper, GABA, bicuculline and picrotoxin were delivered in different experimental conditions to the slice. One, 10 and 100 microM of copper concentration decreased significantly the amplitude and duration of the population spikes in relation to the control response. This effect did not show concentration dependency. Copper in bicuculline medium decreased significantly the duration response in relation to the control response and in relation to copper effect in a free bicuculline medium. This phenomenon emphasizes the copper action on the GABA (B) and (C) receptors. Copper in a picrotoxin medium increased significantly the excitability of the response. This new effect suggests that copper acts on non-GABA receptors, an effect that could be detected when the GABA receptors were inactivated. As a result of these findings it appears that, under our experimental conditions, copper generated transient sensitivity changes in pyramidal neurons of CA1 dorsal hippocampus.

Action Potentials↗
PubMed2000

Donor and recipient postoperative complications in living related kidney transplantation. A multicentric study.

BACKGROUND: Living related kidney transplantation is considered a gold standard of renal transplantation in order to overcome end-stage renal disease within the same family members. Living donation, albeit decreasing cadaveric donor shortage, exposes donors to the risk of surgical complications. METHODS: In order to assess the postoperative complication rate in donors and recipients, we reviewed retrospectively 90 consecutive living related kidney transplants in a multicentric study. All nephrectomies were performed extraperitoneally through a left flank incision. RESULTS: Major perioperative complications (first 3 weeks after surgery) occurred in 12 subjects: these included bleeding (2.2%), symptomatic pneumothorax (1.1%), iliac thrombophlebitis (3.3%), iliac artery dissection (1.1%), laparotomic dehiscence (2.2%), perirenal hematoma (1.1%), renal artery stenosis (1.1%), urinary fistula (1.1%). Minor perioperative complications took place in 8 cases. One recipient died. Donor postoperative major complications occurred in 2 subjects. CONCLUSIONS: On the basis of these results we conclude that living related kidney transplantation is an important treatment of end stage renal disease, due to the associated low major complication rate and the high feasibility of this methodology.

Adolescent↗
PubMed1997

Growth factors and myointimal hyperplasia in experimental aortic allografts.

OBJECTIVES: To analyse the role of growth factors (platelet derived growth factor, PDGF; basic fibroblast growth factor, bFGF; interleukin 1, IL-1) in the genesis of myointimal hyperplasia in arterial allografts. MATERIALS: Two groups of experiments were performed: isografts and allografts. The isograft group consisted of 15 inbred Lewis rats in which a 1 cm long segment of aorta was inserted as an abdominal aortic interposition graft. The aortic segments were obtained from syngenic Lewis rats. The allograft group consisted of 15 inbred Lewis rats, in which a 1 cm long segment of aorta was interposed at the abdominal aorta level. The aortic segments were obtained from allogenic Brown-Norway rats. CHIEF OUTCOME MEASURES: The animals were killed 4 weeks after surgery and were analysed by morphometric analysis (n = 3 for each group). In addition, production of PDGF, bFGF and IL-1 by aortic segments (n = 12 for each group) in organ culture was assessed. MAIN RESULTS: Allografts had more myointimal hyperplasia, than isografts (p < 0.05). PDGF and bFGF production, generally considered to be the cause of myointimal hyperplasia, was not increased in allografts. IL-1 production was higher in allografts (p < 0.001). MAIN CONCLUSIONS: Myointimal hyperplasia in aortic allografts is dependent on growth factors produced by the graft itself. These growth factors are different from PDGF and bFGF that generally have been implicated in the genesis of naturally occurring myointimal hyperplasia and atherosclerosis. IL-1 may have a principal role in the genesis of myointimal hyperplasia in arterial allografts.

3T3 Cells↗
PubMed1997

Upregulation of Calbindin-D-28k immunoreactivity by excitatory amino acids.

Excessive or prolonged exposure to excitatory amino acids (EAA) are thought to be neurotoxic by altering calcium homeostasis. A protective role of Calbindin-D-28 k (Calbindin) has been postulated due to its capacity to buffer calcium. Calbindin is highly expressed in the Purkinje cells (PCs), of the cerebellar cortex. Changes of the Calbindin immunoreactivity (IR) by the EAA has been here investigated in cerebellar slices maintained in vitro. It was found that at low temperature, PCs are very slightly immunoreactive and therefore the experiments were done at 22 degrees C. The results show that Calbindin-IR increases in PCs exposed to the neurotoxic agonists, Kainic acid (KA) and AMPA as well as to glutamate (Glu), the endogenous EAA. The increase is very rapid and slowly reversible; is induced by excitatory and excitotoxic concentrations of the agonists; is independent of the calcium influx. While KA- and AMPA-induced Calbindin-IR is blocked by CNQX, the KA/AMPA receptor antagonist, Glu-induced Calbindin-IR is only slightly decreased by CNQX and AP5, the NMDA receptor antagonist. It is concluded that Calbindin-containing neurons can increase their calcium buffering capacity in response to EAA binding to specific receptors, the response being independent of, but concomitant to calcium influx.

Animals↗
PubMed1996

Neuronal changes induced by chronic toluene exposure in the cat.

Chronic toluene inhalation provokes significant deleterious neurological effects in young glue sniffers and exposed workers. We have developed a chronic toluene inhalation model in the cat to address this issue. Neuronal changes using Loyez and acid fuchsinegallocianine stainings were studied at prefrontal cortex, cerebellun and hippocampus. All this structures showed varying degrees of neuronal degeneration to necrosis. Even if injury signs were widespread, the neuronal layers weren't equally affected and there were clear differences in injury severity. In the prefrontal cortex, injured neurons were observed in layers II, III and V/VI extending over several gyri. Lesions were time related, as was more clearly observed in Purkinje cells. In dorsal hippocampus alterations were particulary severe in CA1 and CA3. In ventral hippocampus damaged neurons were scarce and located mainly in CA2. The possible relation of this findings with behavioral changes observed during chronic toluene inhalation are noted.

Administration, Inhalation↗
PubMed1993

Glutamate, GABA, calbindin-D28k and parvalbumin immunoreactivity in the pulvinar-lateralis posterior complex of the cat: relation to the projection to the Clare-Bishop area.

Neurons of the pulvinar-lateralis posterior complex (Pul-LP) containing glutamate (Glu) and GABA, as presumed neurotransmitters, and calbindin- D28k (calbindin) and parvalbumin (PV), as Ca-binding proteins, were identified in the cat by using immunohistochemical methods. In vibratome sections, neurons immunoreactive (IR) to each of the four antibodies were observed throughout the Pul-LP. In semithin sections, GABA-IR neurons were also PV-IR but not calbindin-IR and some of them also co-localized Glu. The Glu-IR neurons which were negative for GABA co-localized calbindin but not PV. The neurons of the Pul-LP projecting to the Clare-Bishop area (CB) in the suprasylvian gyrus were identified with a retrogradely transported tracer and the sections were then immunostained for Glu, GABA, calbindin and PV. Only Glu- and calbindin-IR neurons were retrogradely labeled. These results show that, if calbindin and PV have a Ca-binding role, the presumably excitatory Glu-IR neurons projecting to the CB are use calbindin whereas the presumably inhibitory GABA-IR neurons are intrinsic and use PV. This relationship implies that these proteins probably have other roles specifically related to the kind of agonist to be released at the neuron.

Animals↗
PubMed1993

Cytoplasmic calcium buffer, calbindin-D28k, is regulated by excitatory amino acids.

Excessive intracellular calcium in neurones is thought to underlie the pathophysiology of several neurodegenerative diseases. An extensively studied animal model is the neurotoxic increases in intracellular Ca2+ induced by excitatory amino acid. We report here that the calcium-binding protein, calbindin-D28k, increases rapidly in Purkinje cells of rat cerebellar slices superfused with excitatory and excitotoxic concentrations of glutamate or its analogue, kainic acid. The increase is reversible and reproducible, is blocked by CNQX and is independent of Ca2+ influx. These results indicate that calbindin containing neurones can regulate their Ca2+ buffering capacity in response to a specific agonist and this regulation is not mediated by cytosolic calcium increases.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1993

[The parenteral administration of essential amino acids in patients on periodic hemodialysis treatment. A pilot study].

In an attempt to improve the nutritional status of seven hemodialysed patients, 500 ml of a 5.5% nephrological essential amino acid solution (EAA) were administered during each dialysis session for 2 months. At the end of this treatment, a significant increase in albuminemia was found (p < 0.05). These results are an encouragement to continue this therapy, especially if it is kept in mind that the half-life of albumin is much shorter than the period of EAA administration.

Adolescent↗
PubMed1993

[Radiographic examination of the pelvis in patients under periodic hemodialysis for terminal uremia].

Significant signs of uremic osteodystrophy were found at Rx examination of the pelvis in 29 out of 72 uremic patients (40%) undergoing maintenance hemodialysis. It is therefore thought that Rx of the pelvis, although it is more significant for some signs (brown tumors, alterations of the trabecular structure, enlargement of Ward's triangle) than for others, such as subperiosteal resorption, should not be neglected in these patients.

Adolescent↗
PubMed1991

The immunocytochemical distribution of calbindin-D28k and parvalbumin in identified neurons of the pulvinar-lateralis posterior complex of the cat.

The calbindin-D28k and parvalbumin immunoreactivities of the neurons of the pulvinar-lateral posterior complex (Pul-LP) were studied in the cat. The neurons of the Pul-LP projecting to the cerebral cortex were identified by a retrogradely transported tracer injected in the suprasylvian gyrus. Two populations of cells were found, a calbindin-D28k-immunoreactive, large-diameter population and a parvalbumin-immunoreactive, small-diameter group. The two kinds of cells are closely intermingled. The former includes the neurons retrogradely marked, and therefore projecting to the suprasylvian gyrus. The latter includes neurons which were not retrogradely marked, and therefore presumably intrinsic elements.

Animals↗
PubMed1991

Recovery cycle of the cerebral neocortex: preliminary observations in epileptic patients.

The recovery cycle of the amplitude of the potential evoked in the cerebral neocortex by paired electrical stimuli of the underlying white matter was studied in 5 epileptic patients with intracerebral electrodes chronically implanted stereotactically. A reproducible pattern was apparent for the late components of the potential (i.e., the peak-to-peak amplitude between the second and the third peak, with an average peak latency of 14 and 35 ms, respectively). There was an early period of facilitation (5-10 ms interstimulus interval) followed by a period of relative or absolute depression (20-100 ms) with recovery at an interstimulus interval of about 150 ms. The recovery function of the early components of the potential (i.e., the peak-to-peak amplitude between the first and the second peak, with an average peak latency of 6 and 14 ms, respectively) was variable; recovery was reached at about 150 ms. The responsiveness seemed less in the most epileptogenic cortical areas.

Afferent Pathways↗
PubMed1990

[Brief treatment with thymopentin as adjuvant in vaccination for hepatitis B: controlled study in patients on periodic hemodialysis].

Eleven hemodialysis patients (9 M, 2 F, aged 65 +/- 20 yrs) (Group A) were treated with thymopentin (TP-5) 50 mg as adjuvant therapy to HB vaccination, with 3 weekly administrations, the week before and the two following the first dose of Pasteur vaccine, 5 micrograms. The percentage of patients developing a sufficient antibody titer (20 mUI/ml) after 4 vaccine doses was not statistically different from that obtained among control groups B and C. The age- and sex- matched controls received the same vaccine schedule without adjuvant. The percentages were as follows: Group A 54.5%, Group B 63.6%, Group C 60%. No local or systemic side effects were encountered after the TP-5 administration. The authors suggest that a short TP-5 treatment as an adjuvant therapy to HB vaccination is not effective in patients maintained on hemodialysis.

Adjuvants, Immunologic↗