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M Braga

Publications and source records attributed to M Braga.

At least 37 records · Page 2Linked to original sources
PubMed2001

Clinical review 129: Oral cholecystographic agents and the thyroid.

Oral cholecystographic agents (OCAs) are known to affect thyroid hormone metabolism by acting as potent inhibitors of type I and type II deiodinases, blocking the conversion of T(4) to T(3) and rT(3) to T(2). In addition, iodine released from the drug blocks thyroid gland secretion of thyroid hormone. These properties make OCAs a potentially useful drug therapy in patients with hyperthyroidism and other thyrotoxic disorders. Short-term treatment with OCAs rapidly reduces serum T(3) levels, with a lesser effect on T(4) levels. OCAs are not useful for long-term treatment, which is usually followed by exacerbation of hyperthyroidism with continued use. The lack of significant side effects makes these drugs an excellent short-term option in situations where a rapid clinical improvement is critical.

Administration, Oral↗
PubMed2001

Efficacy of ultrasound-guided fine-needle aspiration biopsy in the diagnosis of complex thyroid nodules.

Cystic thyroid nodules are considered to be one of the major causes of nondiagnostic and false-negative results on conventional fine-needle aspiration biopsy, thus limiting the potential of this method for the evaluation of complex (solid-cystic) thyroid nodules. Although ultrasound-guided fine-needle aspiration biopsy has emerged as a highly effective diagnostic method for the assessment of nonpalpable and difficult to palpate nodules, its role in complex nodules has not yet been carefully evaluated. In this study, we report the efficacy of ultrasound-guided fine-needle aspiration biopsy in 124 complex nodules in 113 patients. This method proved to be highly effective, yielding a satisfactory specimen for cytological evaluation in 94% of the nodules, suggesting that it is an excellent modality for the evaluation of complex nodules and also for the reevaluation of those nodules with a nondiagnostic result on conventional fine-needle aspiration biopsy.

Adult↗
PubMed2001

The value of an immunoenzymatic test (enzyme-linked immunosorbent assay) for the diagnosis of strongyloidiasis in patients immunosuppressed by hematologic malignancies.

The diagnosis of strongyloidiasis relies upon the identification of the parasite in stool samples. In 1981, a serologic assay was developed, which was useful in the diagnosis of strongyloidiasis in the immunocompetent host. In the present study, we evaluated the enzyme-linked immunosorbent assay (ELISA) in patients with hematologic malignancies. Between April 1995 and December 1998, sera from 164 consecutive patients were tested for the presence of IgG antibody to Strongyloides stercoralis. Patient was considered uninfected after at least three negative stool examinations. The prevalence of strongyloidiasis was 13%. The underlying diseases were acute leukemia in 21% and lymphoma in 52% of the patients. The majority of the patients were receiving chemotherapy (93%) and steroids (76%). The sensitivity, specificity, and positive and negative predictive values were 68%, 89%, 48%, and 95%, respectively. The ELISA may be an excellent assay to rule out the diagnosis of strongyloidiasis in patients with hematologic malignancies.

Adult↗
PubMed2001

The pathogenesis of ALS: implications for treatment strategies.

Besides the free radical hypothesis raised by the identification of Superoxide Dismutase I mutations in a subset of familiar Amyotrophic Lateral Sclerosis (ALS) patients, three etiopathogenic hypotheses for sporadic ALS, namely autoimmune, neurofilament, and glutamate toxicity, have attracted interest in the last few years. The role of autoimmunity in ALS has been seriously questioned. The excitotoxic hypothesis for ALS spurred two clinical trials with riluzole. The results of both studies showed a modest benefit in prolonging survival that was statistically significant. Riluzole was the first drug made available for ALS patients. It began a new era in both basic and clinical research. Various human recombinant neurotrophic molecules (CNTF, BDNF, IGF-I) were administered to ALS patients. IGF-I slowed the progression of functional impairment in patients with ALS with no adverse effects. The recent demonstration of the specific viral echovirus 7 RNA sequences in the spinal cord of ALS patients refocused research on the viral hypothesis of the disease and antiviral drugs are ready to be used in clinical settings. New treatment strategies are today under study: intrathecal infusion with BDNF, intrathecal capsules for neurotrophic factor secretion or in vivo gene therapy using viral vectors. New research findings are, more than for other diseases, immediately transferred to clinical ground for the desperate need of a curative treatment of the patients affected by ALS.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Latex Fractionation by Sedimentation and Colloidal Crystallization: The Case of Poly(styrene-co-acrylamide).

Poly(styrene-co-acrylamide) (PS-AAM) latex was prepared, fractionated by sedimentation under gravity, and characterized by PCS, infrared spectra, secondary and backscattered electron imaging in the scanning electron microscope, and electron spectroscopy imaging in an analytical transmission electron microscope. Three latex fractions were obtained. The lower fraction was opalescent and its particles were the more uniform, concerning size, chemical composition, and topochemical features. This lower fraction was still further fractionated by zonal centrifugation in a density gradient, yielding two fractions with similar macrocrystal-forming abilities but different sizes and chemical compositions. These results confirm those previously obtained for the PS-HEMA latex. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Latex Surface and Bulk Coagulation Induced by Solvent Vapors.

Latex exposure to solvent vapors leads to highly specific changes in latex stability as well as on the morphologies of the particle association products, depending on the latex and solvent used. Examples of solvent vapor-induced aggregation are given: surface films are obtained on two PS latexes; in one case, the film surface is mirror-reflective and very flat, as evidenced by AFM. Another PS latex coagulates under exposure to acetone vapors, and the morphologies of the coagula are highly sensitive to the exposure conditions. This latex yields a highly porous foam-like structure, in which particles are strongly coalesced but form percolating patches around the pores. The same latex but under other conditions produces a coagulum of large numbers of aggregated particles with a raspberry-like morphology. Density centrifugation experiments show that the effect of solvents on different latex fractions is not uniform, and some fractions show larger density changes than others, thus evidencing a variability in their swelling ability. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Altered microperfusion at the rectal stump is predictive for rectal anastomotic leak.

PURPOSE: The aim of this study was to evaluate the reliability of intraoperative laser-Doppler measurements in predicting the occurrence of anastomotic leak in patients with colorectal cancer undergoing stapled straight anastomosis to the rectum. METHODS: A prospective study was undertaken on 55 patients with rectal cancer or distal sigmoid cancer programmed for elective curative surgery. In all patients transmural colonic blood flow was measured by laser-Doppler flowmetry technique before bowel manipulation (baseline measurement) and after vascular ligation and division. Comorbidities at admission, intraoperative events, associated surgical procedures, and clinical outcome were tested for any association with anastomotic leak. RESULTS: Postoperative mortality was 1.8 percent (1/55 patients), and the overall morbidity was 21.3 percent. Anastomotic leak occurred in eight patients (14.5 percent). After colonic division a blood flow reduction at the rectal stump was observed in 42 patients (76.3 percent) as compared with baseline measurement. The mean rectal stump flow reduction was 6.2 percent in patients without anastomotic leak, whereas in patients who developed anastomosis breakdown it was 16 percent (P < 0.001). Mean proximal stump flow reduction was 5.1 percent in the uncomplicated patients, whereas in patients who had an anastomosis breakdown it was 12.9 percent (P < 0.01). A positive linear correlation was found between decrease in blood flow and rate of anastomotic leak. CONCLUSION: Blood flow reduction at the rectal stump is associated with an increased risk of anastomotic leak.

Analysis of Variance↗
PubMed2000

Motor neurones in culture as a model to study ALS.

Defining the basis of the selective cell vulnerability of motor neurones (MN) represents the key issue in amyotrophic lateral sclerosis (ALS), and tissue culture models are the ideal system for the identification of the MN specific features at the single cell level. Neurone-astrocyte metabolic interactions, which have a critical role in MN through glutamatergic toxicity, have been mostly defined in vitro. Ca++ metabolism, which appears to play a critical role in inducing MN loss in ALS, has been successfully studied using in vitro cell models. Furthermore, primary cultures demonstrated that apoptotic or necrotic death of neurones after injury depends upon the cell energetic status. Superoxide dismutase- (SOD-1) mutations were successfully expressed in cultured rodent MNs, providing a critical assay to sequence the molecular processes responsible for MN degeneration due to the identified genetic defect. The recent identification of genes that separate humans from apes further increases the value of the human in vitro models to better understand specific human cellular properties. Purified human MNs and astrocytes can today be obtained from the human embryonic spinal cord anterior horns. Interactions at the single cell level can be dissected using the cDNA amplification techniques. The effects of molecules affecting MN survival, neurite extension, and metabolism can easily be defined in vitro, gaining a critical mass of information of immediate clinical application in the treatment of patients affected by ALS. Understanding the properties of human MNs in vitro represents today a significant and critical tool that can easily be reached after extension of the available knowledge from non-primate to human research. Human MN culture studies can greatly contribute to identifying the primitive critical cellular events responsible for the MN degeneration observed in ALS and to gaining crucial information on new therapeutical agents.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Coupled plasma filtration-adsorption in a rabbit model of endotoxic shock.

OBJECTIVE: To test the hypothesis that nonselective adsorption by a hydrophobic resin of cytokines and other proinflammatory mediators could improve 72-hr survival in a rabbit model of endotoxic shock. DESIGN: Prospective, randomized, controlled animal trial. SETTING: Animal care facility at a research institution. SUBJECTS: A total of 109 New Zealand white male rabbits. INTERVENTIONS: Anesthetized rabbits were cannulated with indwelling femoral arterial and venous lines. Septic shock was induced by a single intravenous injection of Escherichia coli lipopolysaccharide. The dose was experimentally assessed in 40 rabbits receiving 1.0, 0.5, 0.1, and 0.05 mg/kg body weight to determine LD80 at 72 hrs. Extracorporeal circulation consisted of plasma filtration coupled with passage of the plasma filtrate through a hydrophobic sorbent and reinfusion into the venous line. The extracorporeal treatment lasted for 3 hrs. Rabbits injected with endotoxin (0.05 mg/kg) were submitted to plasma filtration with (19 rabbits) or without (20 rabbits) sorbent adsorption. As controls, rabbits injected with vehicle alone were treated with plasma filtration (ten rabbits) or without (ten rabbits) sorbent adsorption. Ten rabbits were monitored under anesthesia to determine basal survival. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of endotoxin, bioactive tumor necrosis factor, resin-adsorbed platelet-activating factor, mean arterial pressure, base excess, and white cell count were assessed and a global severity score was established. At 72 hrs, cumulative survival was significantly (p = .0041) improved in septic rabbits treated with coupled plasma filtration-adsorption. Circulating tumor necrosis factor bioactivity remained similar in control and treated rabbits. Biologically significant amounts of platelet activating factor were eluted from the sorbent during the entire treatment time. The severity score inversely correlated with survival (p < .001). CONCLUSIONS: Coupled plasma filtration-adsorption improved survival in a rabbit model of endotoxic shock. Coupled plasma filtration-adsorption may be an extracorporeal treatment capable of removing structurally different inflammatory mediators associated with sepsis.

Animals↗
PubMed2000

Artificial nutrition after pancreaticoduodenectomy.

Patients undergoing pancreaticoduodenectomy (PD) often require postoperative artificial nutrition. This trial was undertaken to evaluate whether the route of administration and the composition of the postoperative nutritional support could affect the immunometabolic response and outcome. A prospective, randomized trial was carried out in 212 subjects who underwent PD. Patients were randomized to receive a standard enteral formula (standard group, n = 73) or an enteral formula enriched with arginine, omega-3 fatty acids, and RNA (immunonutrition group, n = 71), or total parenteral nutrition (parenteral group, n = 68). Postoperative feeding started 6 hours after surgery. The three regimens were isocaloric and isonitrogenous. Assessed parameters were phagocytosis ability of polymorphonuclear cells, plasma interleukin-2 receptors, C-reactive protein, retinol binding protein, tolerance of enteral feeding, rate of postoperative complications, and length of hospital stay (LOS). Full nutritional goal (25 kcal/kg) was achieved in 87% of enterally fed patients versus 95% in the parenteral group. Subjects receiving immunonutrition had a significantly better recovery of the immunometabolic parameters on postoperative day 8 compared to the other two groups. The rate of postoperative complications was lower in the immunonutrition group (33.8%) than in either the standard (43.8%) or parenteral group (58.8%) (p = 0.005 immunonutrition vs. parenteral). Also, the mean LOS was shorter in the immunonutrition group than in the standard and parenteral groups (15.1 vs. 17.0 vs. 18.8 days, respectively; p < 0.05). Early postoperative enteral feeding may safely and effectively replace parenteral nutrition in patients undergoing PD. Immunonutrition ameliorates the immunometabolic response and improves outcome compared to parenteral feeding.

Adult↗
PubMed2000

Health care resources consumed to treat postoperative infections: cost saving by perioperative immunonutrition.

The objectives of the study were to calculate the costs of postoperative complications and to evaluate whether the use of perioperative enteral immunonutrition, may lead to a saving in health care resources consumed. The economic analysis was based on data from a randomized double-blind trial that include 206 cancer patients who received perioperatively either enteral immunonutrition (treatment group, n = 102) or a standard enteral diet (control group, n = 104). Estimates of costs were based on resource use for treatment of complications, which were valued according to the National List of Sanitary Costs of the Italian Ministry of Health and on the medical Diagnosis-Related-Group (DRG) reimbursement rates. Costs of nutrition were also calculated. Cost comparison and cost effectiveness analyses were then carried out. Intent-to-treat analysis showed that the total costs of 52 postoperative complications were 322,218 euros, with a consumption of the DRG reimbursement rate of 15.4%. The costs of nutrition were 35,437 euros in the treatment group versus 10,768 euros in the control group. The total costs (nutrition plus treating complications) amounted to 113,778 euros in the treatment group versus 254,450 euros in the control group. The mean total costs per patient were 1,115 euros in the treatment group versus 2,447 euros in the control group (P = 0.04). Effectiveness was 83.3% in the treatment group versus 68.3% in the control group (P = 0.009). Cost effectiveness analysis showed a net saving of 2,386 euros per complication-free patient in favor of the treatment group. In conclusion, the perioperative use of immunonutrition appears cost effective due to a substantial saving of resources used to treat postoperative complications.

Aged↗
PubMed2000

Rational base and clinical results of immunonutrition.

The use of enteral formulas supplemented with immunonutrients has been demonstrated to modulate gut function, inflammatory and immune response after trauma in both experimental and clinical settings. Most studies have focused on glutamine, arginine, w-3 fatty acids and nucleotides. Glutamine is an important source of nitrogen and calories and might be particularly useful in depleted patients or in patients affected by small bowel syndrome. Its use in the critical patient remains controversial. Data collected in two different recent metaanalysis consistently confirmed that enteral formulas enriched with, arginine, w-3 fatty acids and nucleotides reduced infectious complications and hospital stay after planned surgery, and decreased infectious complications, hospital stay and ventilator days in the critically ill. Mortality seems not to be affected by enteral administration of immunonutrients.

Arginine↗
PubMed1999

Perioperative immunonutrition in patients undergoing cancer surgery: results of a randomized double-blind phase 3 trial.

HYPOTHESIS: Perioperative administration of a supplemented enteral formula may reduce the rate of postoperative infections. DESIGN: Prospective, randomized, double-blind clinical trial. SETTING: Department of surgery at a university hospital. PATIENTS: Two hundred six patients with neoplasm of colorectum, stomach, or pancreas. INTERVENTION: Patients were randomized to drink 1 L/d of either a control enteral formula (n = 104) or the same formula enriched with arginine, RNA, and omega3 fatty acids (n = 102) for 7 consecutive days before surgery. The 2 diets were isoenergetic and isonitrogenous. Jejunal infusion with the same formulas was started 6 hours after operation and continued until postoperative day 7. MAIN OUTCOME MEASURES: Rate of postoperative infectious complications and length of hospital stay. RESULTS: Both groups were comparable for age, sex, weight loss, Karnofsky scale score, nutritional status, hemoglobin level, duration of surgery, blood loss, and rate of homologous transfusion. Intent-to-treat analysis showed a 14% (14/102) infectious complication rate in the supplemented group vs 30% (31/104) in the control group (P = .009). In the eligible population, the postoperative infection rate was 11% (9/85) in the supplemented group vs. 24% (21/86) in the control group (P = .02). The mean +/- SD length of postoperative stay was 11.1+/-4.4 days in the supplemented group and 12.9+/-4.6 in the control group (P = .01). CONCLUSION: Perioperative administration of a supplemented enteral formula significantly reduced postoperative infections and length of stay in patients undergoing surgery for cancer.

Adolescent↗
PubMed1999

Effect of recombinant human nerve growth factor on cisplatin neurotoxicity in rats.

In this study we evaluated the effect of recombinant human nerve growth factor (rhNGF) on cisplatin (CDDP)-induced sensory neuronopathy in an experimental paradigm in the rat. Young adult female Wistar rats were treated with CDDP (2 mg/kg ip twice weekly for nine times) alone or in combination with rhNGF (1 mg/kg sc on alternate days). The effect of CDDP +/- NGF treatment was evaluated with behavioral (tail-flick test) and neurophysiological (nerve conduction velocity in the tail) methods immediately after treatment and after a follow-up period of 6 weeks. Pathological and morphometrical examinations of the dorsal root ganglia (DRG) and sciatic and saphenous nerves were also performed. rhNGF treatment induced a significant reduction in the CDDP-induced decrease in nerve conduction velocity (P < 0.05), and this was associated with a significant protection against the decrease in somatic (P < 0.05), nuclear (P < 0.05), and nucleolar size (P < 0.01) caused by CDDP treatment. However, for each of the parameters examined the neuroprotection obtained with rhNGF treatment was not complete. At the follow-up examination no differences between the three groups were observed in tail-flick test and nerve conduction velocity. We conclude that rhNGF, administered according to the schedule used in this experiment, exerts a biologically significant neuroprotective effect against CDDP peripheral neurotoxicity.

Animals↗
PubMed1999

Myelinolytic lesions in spinal cord of cobalamin-deficient rats are TNF-alpha-mediated.

Repeated intracerebroventricular (i.c.v.)microinjection of tumor necrosis factor-alpha (TNF-alpha) into normal rats causes intramyelin and interstitial edema in the white matter of the spinal cord (SC). This response is identical to that observed in the SC white matter of rats made cobalamin (Cbl) deficient by total gastrectomy (TG). Immunoblot analysis showed that: 1) the level of the biologically active form of the TNF-alpha protein (17 kDa) is higher in the SC of totally gastrectomized (TGX) rats 2 months after TG, i.e., at the postoperative time when edema is observed; 2) SC levels of TNF-alpha protein (17 kDa) in 2-mo-TGX-, Cbl-treated rats are reduced to control. Repeated i.c.v. microinjections of anti-TNF-alpha antibodies, transforming growth factor-beta1 (TGF-beta1) or interleukin-6 (IL-6) into TGX rats, begun shortly after TG, substantially reduced both intramyelin and interstitial edema in the SC white matter. This study provides the first evidence that the hallmark myelin damage of Cbl-deficient central neuropathy, which is a pure myelinolytic disease, is not caused directly by the withdrawal of the vitamin itself, but reflects enhanced production of the biologically active form of TNF-alpha by SC cells. This study thus supports the view that TGF-beta1 and IL-6 may act as neuroprotective agents in Cbl deficiency central neuropathy.

Animals↗
PubMed1999

Complications of pancreatic surgery and the role of perioperative nutrition.

BACKGROUND: According to international guidelines, artificial nutrition may be indicated after pancreaticoduodenectomy (PD). This clinical study was designed to evaluate whether the route of administration and the composition of the postoperative nutritional support could affect outcome. METHODS: One hundred patients who underwent PD for cancer of the pancreatic head were prospectively studied. Patients were randomized to receive a standard enteral formula (SEN; n = 35) or immunonutrition with an enteral formula enriched with arginine, omega-3 fatty acids, and RNA (IEN group; n = 33), or total parenteral nutrition (TPN; n = 32). Postoperative feeding was started within 12 h after surgery. The three regimens were isoenergetic and isonitrogenous. Tolerance of enteral feeding, rate and severity of postoperative complications, and length of hospital stay (LOS) were evaluated. RESULTS: Full nutritional goal (25 kcal/kg) was achieved in 84% of enterally fed patients versus 96% in the parenteral group (p = NS). The rate of postoperative complications was lower in the IEN group (33%) than in the SEN (40%) and TPN groups (59%). The severity of infectious complications (sepsis score) was lower in the IEN (5.5) than the SEN (7.9) and TPN groups (10.4; p < 0.05). LOS was shorter in the IEN than in the SEN and TPN groups (16.3 vs. 17.8 vs. 19.3 days, respectively; p < 0.05). CONCLUSIONS: In patients undergoing PD the established nutritional goal can be obtained by enteral feeding. Immunonutrition seems to improve outcome.

Adenocarcinoma↗
PubMed1999

A tentative interpretation of electromyographic regional differences in bulbar- and limb-onset ALS.

Electromyography (EMG) could be useful in defining regional motor neuron vulnerability in ALS. We performed EMG in 36 sporadic ALS patients (9 with bulbar-onset and 27 with limb-onset symptoms). Active denervation was more frequent in limb than in corresponding paraspinal muscles, in the thoracic paraspinal, and in the bulbo-cervical muscles in patients with bulbar-onset symptoms. These results are consistent with a regional motor neuron vulnerability along with a nerve length-dependent liability.

Adult↗