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Biomedical subjects

A Valerio

Publications and source records attributed to A Valerio.

At least 19 recordsLinked to original sources
PubMed2005

Comparison of sequential combined spinal-epidural anesthesia and spinal anesthesia for cesarean section.

AIM: The aim of our study was to prove that by using sequential combined spinal-epidural (CSE) anesthesia it is possible to overcome the limits connected to the use of spinal anesthesia (SA) alone for elective cesarean section. METHODS: We examined 100 women submitted to cesarean section; SA was administered to 50 patients and sequential CSE technique to the other 50. In every woman before execution of the anesthesia we infused 500 mL of a plasma expander and a previous administration of 5 mg of ephedrine. The CSE was executed at the L1-L2 intervertebral space, administering in spinal anesthesia 5 mg of levobupivacaine with 5 _g of sufentanil, and in peridural anesthesia 10-12 mL of levobupivacaine 0.25% according to the patient's height. The peridural catheter for postoperative analgesia was then positioned. In the group of women submitted only to SA, 7.5-8 mg of levobupivacaine was injected, according to the patient's height, in the L1-L2 intervertebral space, with 5 _g of sufentanil. We considered the following adverse effects: hypotension; bradycardia; vomiting; intraoperative discomfort and motor block. RESULTS: The results obtained showed that, with a P < or = 0.05, the incidence of motor block (P < 0.001), discomfort (P < 0.001) and hypotension (P = 0.021) in the SA group is greater than in the CSE group. The difference in the incidence of vomiting (P = 0.147) and bradycardia (P = 0.067) between the 2 groups is not statistically significant. CONCLUSIONS: In our opinion sequential CSE can be considered an important step forward in the regional anesthesia used for elective cesarean section.

Anesthesia, Epidural↗
PubMed2004

Altered glucose metabolism and proteolysis in pancreatic cancer cell conditioned myoblasts: searching for a gene expression pattern with a microarray analysis of 5000 skeletal muscle genes.

BACKGROUND AND AIMS: We verified whether conditioned media (CM) from pancreatic cancer cell lines (MIAPaCa2, CAPAN-1, PANC-1, BxPC3) alter glucose metabolism and gene expression profiles (microarray experiment with a platform of 5000 skeletal muscle cDNA) in mice myoblasts. METHODS: Myoblasts were incubated with control or pancreatic cancer CM for 24 and 48 hours. RESULTS: Lactate significantly increased in CM compared with non-conditioned myoblasts. No variations in expression levels of the main genes involved in glycolysis were found in CM myoblasts. Propionyl coenzyme A carboxylase and isocitrate dehydrogenase 3 beta genes, which encode enzymes of the tricarboxylic acid cycle, were overexpressed, while IGFIIR and VAMP5 genes were underexpressed in CM myoblasts. PAFAH1B1 and BCL-2 genes (intracellular signal transduction) and the serine protease cathepsin G (proteolysis), were overexpressed in CM myoblasts. Tyrosine accumulation in CM myoblasts suggested that proteolysis overcomes protein synthesis. Sorcin, actin alpha, troponin T1, and filamin A were underexpressed in CM myoblasts. CONCLUSIONS: Our findings demonstrate that pancreatic cancer cell conditioned media enhanced lactate production and induced proteolysis, possibly by altering expression levels of a large number of genes, not only those involved in protein biosynthesis and degradation or glucose metabolism, but also those involved in the tricarboxylic acid cycle and in vesicle traffic.

Aged↗
PubMed2002

Cytokine imbalance in pregnancies with fetal chromosomal abnormalities.

BACKGROUND: The aim of the present study is to investigate the levels of some of the cytokines which may be involved in the mechanisms leading to the impairment of placental perfusion and to the onset of uterine contractions in pregnancies with fetal genetic abnormalities compared with controls. METHODS: The amniotic fluid and maternal plasma levels of interleukin-6, interleukin-8 and tumour necrosis factor-beta in patients with fetal chromosomal abnormalities were measured, as well as in euploid pregnancies in the seventh week of gestation. RESULTS: An increase of interleukin-6 (P = 0.034) and a decrease of interleukin-8 (P < or =0.0001) in amniotic fluid, and a decrease of interleukin-6 in the maternal plasma (P = 0.026) was shown in pregnancies with fetal chromosomal abnormalities. A positive correlation was observed between amniotic interleukin-8 and serum interleukin-6 in the presence of fetal aneuploidy (P < 0.006). CONCLUSION: Further investigations of cytokine imbalance in pregnancies with poor outcome as a consequence of genetic disorders rather than infection is warranted.

Adult↗
PubMed2001

Alternative splicing of mGlu6 gene generates a truncated glutamate receptor in rat retina.

A novel splice variant of metabotropic glutamate receptor type 6 (mGlu6 receptor) was identified by reverse transcription-polymerase chain reaction amplification and sequence analysis of rat retina cDNA. The new rat receptor isoform (mGlu6b receptor) is characterized by an additional exon of 88 nucleotides containing an inframe stop codon, thus predicting the expression of a truncated protein of 508 amino acids. In situ hybridization reveals mGlu6b receptor mRNA to be predominantly expressed in the outer part of the inner nuclear layer of rat retina, containing ON-bipolar cells. The mGlu6b protein would comprise the extracellular domain of the receptor containing the ligand-binding site, but would lack the transmembrane and intracellular portions, thus possibly acting as a retinal soluble receptor for glutamate.

Alternative Splicing↗
PubMed2001

Identification of novel alternatively-spliced mRNA isoforms of metabotropic glutamate receptor 6 gene in rat and human retina.

Novel splice variants of metabotropic glutamate receptor type 6 (mGlu6 receptor) were identified by reverse transcription-polymerase chain reaction (RT-PCR) amplification and sequence analysis of rat and human retina cDNAs. The new rat mGlu6 receptor mRNA isoform is characterized by an additional exon of 88 nucleotides containing an in frame stop codon, thus predicting the expression of a truncated protein of 508 amino acids. The human retina was found to express two different mGlu6 receptor mRNA variants: one lacking 97 nucleotides from exon 6, the other including five nucleotides of intron 5. These mRNAs would encode truncated receptors of 425 and 405 amino acids, respectively. Both in rats and in humans, the truncated mGlu6 receptor proteins would comprise the extracellular domain but lack the transmembrane and intracellular portion of the receptor, thus possibly acting as retinal soluble receptors for glutamate. Though generated by different patterns of alternative splicing, the inter-species conservation of truncated mGlu receptor molecules strongly suggest their relevance in the regulatory network of glutamatergic neurotransmission.

Alternative Splicing↗
PubMed2001

Serum protein profiles of patients with pancreatic cancer and chronic pancreatitis: searching for a diagnostic protein pattern.

In this study, 13 sera from patients with pancreatic cancer, 9 from chronic pancreatitis and 10 from healthy subjects were analyzed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The MALDI mass spectra revealed the presence of several low molecular weight peptides, among which some were detected only in the sera from both pathological conditions. On the other hand many peptides were observed only in control sera, and were absent in the sera from the two diseases. Therefore, MALDI analysis of the low molecular weight fraction (<10 000 Da) of sera from patients with pancreatic diseases enabled us to identify the presence of some disease-related signals and also some signals characteristic of normal subjects.

Aged↗
PubMed2001

Combination of continuous subcutaneous infusion of insulin and octreotide in Type 1 diabetic patients.

The effect of 7 day continuous subcutaneous infusion of octreotide (200 microg day(-1)) was evaluated in seven insulin-pump treated Type 1 diabetic patients (age 43+/-1.5 year; BMI 25.1+/-0.7 kg m(-2); HbA(1c) 7.4+/-0.3%). A 24-h metabolic and hormonal profile, and a euglycaemic hyperinsulinaemic clamp (0.25, 0.5, 1.0 mg kg(-1) min(-1)), with [3H]glucose infusion and indirect calorimetry, were performed before and after a 7-day octreotide infusion. Mean 24-h plasma glucose was similar before and after octreotide (9.7+/-0.8 vs. 9.1+/-1.0 mmol l(-1)) but insulin requirement dropped by 45% (49+/-4 vs. 27+/-2 U day(-1); P<0.01). Both 24-h plasma hGH and glucagon were suppressed by octreotide (1.85+/-0.35 vs. 0.52+/-0.04 microg l(-1), and 117+/-23 vs. 102+/-14 ng l(-1), respectively). Glucose utilisation increased after octreotide (insulin 0.5 mU kg(-1) min(-1) clamp 3.09+/-0.23 vs. 4.19+/-0.19 mg kg(-1) min(-1); 1 mU kg(-1) min(-1) clamp 5.64+/-0.61 vs. 7.93+/-0.57 mg kg(-1) min(-1); both P<0.05) and endogenous glucose production was similarly suppressed. Glucose oxidation was not affected by octreotide, while the improvement in glucose storage (insulin 1.0 mU kg(-1) min(-1) clamp 3.89+/-0.60 vs. 5.64+/-0.67 mg kg(-1) min(-1), P<0.05) entirely accounted for the increase in glucose disposal. Endogenous glucose production was more effectively suppressed at the two lower insulin infusion rates (P>0.05). Energy expenditure declined after octreotide. Continuous subcutaneous octreotide infusion suppresses counterregulatory hormones, increases insulin-mediated glucose metabolism by enhancing glucose storage, and reduces energy expenditure. These results support a role for counterregulatory hormones in the genesis of insulin resistance and the catabolic state of Type 1 diabetes.

Adult↗
PubMed2000

Neuroprotection by metabotropic glutamate receptor agonists on kainate-induced degeneration of motor neurons in spinal cord slices from adult rat.

Research has provided evidence about the role of excitotoxicity in the pathophysiology of sporadic amyotrophic lateral sclerosis and suggests that AMPA/kainate receptor activation contributes greatly in mediating glutamate injury to motor neurons. The recent finding of variable expression of metabotropic glutamate (mGlu) receptor subtypes in adult rat spinal cord has prompted us to investigate their contribution to the excitotoxic process. We report here that stimulation of mGlu receptors efficiently prevents motor neuron degeneration induced by kainate. The application of kainate to lumbar spinal cord slices from adult rats induced a massive degeneration of motor neurons which became shrunken, dark and TUNEL-positive. On the contrary, no significant neurotoxicity was observed after NMDA application. A blockade of ionotropic non-NMDA receptors by CNQX, and mGlu receptor stimulation, efficiently counteracted kainate-mediated cell death. Among the various agonists for mGlu receptors, we tested 3-hydroxyphenylglycine (3HPG), which selectively stimulates group I mGlu receptors. In addition, we tested 2-(carboxycyclopropyl)glycine (L-CCG-I) and 4-carboxy-3-hydroxyphenylglycine (4C3HPG), two selective agonists for group II receptors, as well as L-amino-4-phosphonobutyrate (L-AP4), a preferential agonist for group III. The results suggest that all three groups of mGlu receptors are involved in inhibiting excitotoxic phenomena mediated by kainate on spinal cord motor neurons. This was despite being localized differently and, possibly, activating different neuroprotective pathways.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2000

A single-institution experience with fistulojejunostomy for external pancreatic fistulas.

External pancreatic fistulas resistant to medical treatment are an indication for surgery. Over the period from May 1986 to March 1999, we operated on 17 patients suffering from a stabilized external pancreatic fistula as a result of surgical treatment for severe acute pancreatitis in 12 cases, chronic pancreatitis in 3, duodenopancreatectomy in 1, and islet cell tumor enucleation in 1. The surgical repair consisted of precise identification of the fistula tract around the drainage tube and its anastomosis with a Roux-en-Y jejunal loop (fistulojejunostomy). The surgical mortality was nil, and the postoperative outcome was uneventful in 12 patients. Four patients experienced surgical complications, all of which were treated conservatively. After a median follow-up of 93 months, 14 patients are still alive and healthy, 1 had died of neoplastic cachexia, and 2 were lost to follow-up. In our experience, fistulojejunostomy appears to be safe, easy to perform, and curative.

Acute Disease↗
PubMed2000

Changes in pancreatic resection for chronic pancreatitis over 28 years in a single institution.

BACKGROUND: Because of advances in knowledge over recent years there is reason to believe that surgical attitudes towards patients with chronic pancreatitis may have changed. METHODS: Some 547 patients were treated surgically for chronic pancreatitis from 1971 to June 1998. Anastomoses were performed in 80 per cent (438 patients) and resections in 20 per cent (109 patients). Indications and type of operation were analysed, as were mortality and morbidity rates and long-term follow-up results, in patients undergoing resection both over the period as a whole and after dividing the series into two subperiods of 14 years. RESULTS: In the second 14-year period, there was a significant reduction in the percentage of resections compared with anastomoses (28 per cent (69 of 244 patients) versus 13 per cent (40 of 303); P < 0.0001), and a significant change in the type of resection with a substantial increase in resections of the head compared with those of the body and tail. Statistically significant reductions occurred in operating times, number of units of blood transfused (mean(s.d.) 4.7(3.6) versus 1.2(1.6) units; P = 0.0001) and mean hospital stay (18 versus 14 days for pylorus-preserving and 12 versus 8 days for left pancreatectomy with splenectomy; P < 0. 01); mortality and morbidity rates also tended to decrease, but not significantly. CONCLUSION: A different pattern has emerged over the years as regards both the type and number of resections performed.

Adolescent↗
PubMed1999

Glucose metabolic alterations in isolated and perfused rat hepatocytes induced by pancreatic cancer conditioned medium: a low molecular weight factor possibly involved.

A serious insulin resistance characterizes pancreatic cancer-associated diabetes mellitus. Elsewhere, we demonstrated that MIA PaCa2 cultured cells secrete a soluble factor responsible for reduced glucose tolerance induced in SCID mice. The intracellular mechanism of insulin resistance was investigated in isolated and perfused rat hepatocytes incubated with MIA PaCa2 conditioned medium. Lactate production was reduced compared to hepatocytes incubated with control medium while 1,2-DAG was increased and PKC was activated in the hepatocytes incubated with MIA PaCa2 conditioned medium. This behavior was not reproduced treating the hepatocytes with the growth factors EGF, interleukin Ibeta, interleukin-6, and TGF-beta1. In an attempt to make a biochemical identification of the hypothesized tumor associated-diabetogenic factors we observed a low molecular weight protein in the conditioned medium, absent in the nonconditioned one, that may be responsible for the described behaviors.

Animals↗
PubMed1999

Restoration of early rise in plasma insulin levels improves the glucose tolerance of type 2 diabetic patients.

The loss of first-phase insulin secretion is a characteristic feature of type 2 diabetic patients. The fast-acting insulin analog lispro provides a therapeutic tool for assessing the metabolic outcome of restoration of an early rise in plasma insulin levels after the ingestion of an oral glucose load. We studied eight type 2 diabetic patients on two different occasions when they received an oral glucose load (50 g) preceded by either human regular insulin or insulin analog lispro (both 0.075 U/kg lean body mass). Tritiated glucose was infused throughout the studies, and the oral glucose was labeled with [13C6]glucose for monitoring systemic and oral glucose kinetics, respectively. Basal plasma glucose (8.2 +/- 0.9 vs. 7.5 +/- 0.8 mmol/l), insulin (224 +/- 21 vs. 203 +/- 21 pmol/l), and endogenous glucose production (10.4 +/- 1.0 vs. 11.1 +/- 1.1 micromol x kg(-1) x min(-1)) were similar on both occasions. In spite of comparable incremental areas under the curve, the time course of plasma insulin concentration was much different. After injection of regular insulin, plasma insulin peaked at 120 min (368 +/- 42 pmol/l), while with lispro, the peak occurred at 60 min (481 +/- 42 pmol/l). Plasma insulin concentration during the last 3 h of the study, however, was lower with lispro compared with regular insulin. The incremental area under the curve of plasma C-peptide was lower with lispro (0.05 +/- 0.01 vs. 0.13 +/- 0.04 micromol/300 min; P < 0.01). After the ingestion of the oral glucose load, plasma glucose concentration increased by 78% at 80-100 min with regular insulin and by 62% with lispro (P < 0.05) and remained lower for the ensuing 3 h. The incremental area under the curve was 46% lower with lispro (715 +/- 109 vs. 389 +/- 109 pmol/300 min; P < 0.01). There was no difference in the two studies in the rate of appearance of the ingested glucose and in the overall rate of glucose disposal. During the initial 90 min, however, the rate of endogenous glucose production was suppressed in a prompter and more profound manner when lispro was administered (1.39 +/- 0.10 vs. 5.00 +/- 1.22 micromol x kg(-1) x min(-1); P < 0.05), while there was no difference in the late prandial phase. These results show that an early rise in plasma insulin levels after the ingestion of a glucose load is associated with a significant improvement in glucose tolerance due to a prompter, though short-lived, suppression of endogenous glucose production. This amelioration in plasma glucose profile prevents late hyperglycemia and hyperinsulinemia. Therefore, restoration of a more physiologic profile of prandial plasma insulin profile represents a rational approach for treatment of type 2 diabetic patients.

Blood Glucose↗
PubMed1998

Opposing regulation of tau protein levels by ionotropic and metabotropic glutamate receptors in human NT2 neurons.

Human NT2-N neurons derived from retinoic acid treatment of the NTera 2 cell line were used to determine the consequences of ionotropic glutamate receptor (iGluR) hyperstimulation and possible modulatory role(s) exerted by metabotropic glutamate receptor (mGluR) activation. We found that NT2-N neurons express the NR1 subunit of N-methyl-D-aspartate (NMDA) iGluRs and mRNA encoding the 1a isoform of mGluRs. A 15 min pulse with 100 microM NMDA induced an increase in the levels of tau proteins in NT2-N cells. This effect was prevented by incubating NT2-N neurons in the presence of the mGluR agonist (1 S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD). This phenomenon was related, in terms of doses and time, with the observed 1S,3R-ACPD-mediated protection against NMDA-induced NT2-N cell death. Our findings suggest that iGluRs and mGluRs might participate in the control of human neuron viability by differentially affecting the expression of tau proteins.

Cell Death↗