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Biomedical subjects

M Rivero

Publications and source records attributed to M Rivero.

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

Dendroaspis natriuretic peptide in hepatic cirrhosis.

OBJECTIVES: Dendroaspis natriuretic peptide (DNP) is a novel peptide that is structurally similar to atrial, brain, and C-type natriuretic peptides. Many natriuretic peptides are increased in hepatic cirrhosis, but the role of DNP in cirrhosis is unknown at present. The aim of the study was to investigate plasma levels of dendroaspis natriuretic-like immunoreactivity in cirrhosis. METHODS: We measured plasma concentrations of DNP by radioimmunoassay methods in 12 cirrhotic patients without ascites and 44 cirrhotic patients with ascites, and compared these values with 20 age-matched healthy subjects. Renal function, plasma cGMP concentration, plasma renin activity, and plasma endothelin concentration were measured in each patient. RESULTS: Patients without ascites had circulating levels of DNP similar to those of healthy subjects. By contrast, patients with ascites had increased circulating DNP levels compared to both patients without ascites and healthy subjects. In addition, circulating levels of DNP increased in relation to the severity of cirrhosis. Significant positive correlations were also found between DNP levels, endothelin concentrations, and plasma renin activity. CONCLUSIONS: The results of this study indicate that plasma DNP is increased in cirrhotic patients with ascites.

Adult↗
PubMed2000

Computed tomography of normal cranioencephalic structures in two horses.

The purpose of this investigation was to define the anatomy of the cranioencephalic structures in horses using computed tomography (CT). Transverse images of two isolated equine cadaver heads were obtained using a Toshiba 600 HQ (third-generation equipment TCT). CT images were compared to corresponding frozen cross-sections of the cadaver head. Relevant anatomical structures were identified and labelled at each level. The resulting images provided excellent anatomic detail of the structures of the central nervous system and associated formations. Annotated CT images from this study are intended as a reference for clinical CT imaging studies of the equine head.

Animals↗
PubMed2000

Use and misuse of antimicrobial agents in a general hospital in the AIDS era.

A prevalence study was carried out to ascertain the pattern of antimicrobial use, costs and relevance in a general hospital during the AIDS era. All patients receiving antimicrobials were studied. Antimicrobials were divided into antibacterial drugs and others and the costs evaluated in US dollars. Of 1526 patients surveyed, 455 (29.8%) were receiving 664 courses of antimicrobials: 109 (7.2%) as prophylaxis and 346 (22.6%) as treatment. Fifteen percent of courses involved non-antibacterial drugs. In 188 patients (40.9% of those treated) treatment was inadequate, usually because of incorrect drug choice. Daily cost of antimicrobials was $14953. AIDS accounted for 3% of all patients, 9% of those receiving antimicrobials, 19.7% of antimicrobial usage and 9.6% of the antimicrobial expenditure. Misuse occurred in 43% of non-HIV patients and 17% of those with HIV. Thus, despite a disproportionate contribution of patients with AIDS, adequacy of use of antimicrobials was better in this population.

AIDS-Related Opportunistic Infections↗
PubMed2000

Involvement of the fas system in hepatitis C virus recurrence after liver transplantation.

To date, there have been no reports of the involvement of the Fas system in recurrent hepatitis C virus (HCV) infection after orthotopic liver transplantation (OLT). In 25 patients who underwent OLT for HCV-related liver cirrhosis, we evaluated the expression of the Fas antigen (FasAg) on hepatocytes, apoptic hepatocytes, and serum levels of soluble Fas (sFas). The level of HCV viremia and HCV genotype were determined by polymerase chain reaction. Serum sFas levels were determined by an enzyme immunoassay procedure. DNA fragmentation was determined by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) technique on deparaffinized liver samples. FasAg expression was evaluated by an immunoperoxidase method. Sixteen patients had evidence of recurrent HCV disease. The number of hepatocytes expressing FasAg and the percentage of apoptotic hepatocytes was greater among patients who developed recurrent hepatitis than among those who did not (P <.01 and P <.0001, respectively). There was a correlation between hepatic expression of FasAg, intensity of lobular inflammation (P =.007), and TUNEL index (P <.001). The levels of sFas were greater among the patients with recurrent HCV hepatitis than those without recurrent hepatitis (P <.04). We conclude that (1) Fas expression is up-regulated in recurrent HCV after OLT and is related to the grading of liver disease; likewise, levels of sFas were greater in the patients with recurrent HCV hepatitis; and (2) the demonstration of hepatocytes with FasAg expression and the labeling of the nuclei by TUNEL assay suggest that hepatic apoptosis mediated by the Fas system may have a role in the pathogenesis of recurrent HCV hepatitis after OLT.

Adult↗
PubMed2000

[1,3-Bis(diphenylphosphino)propane]trichlorooxorhenium(V).

Trichlorooxo[1,3-propanediylbis(diphenylphosphine)-P,P ']rhenium(V), [ReCl(3)O(C(27)H(26)P(2))], crystallizes with four formula units per unit cell. The crystal structure consists of neutral complexes of [ReOCl(3)(dppp)] [dppp is 1,3-bis(diphenylphosphino)propane] packed by H.pi-ring interactions. The Re atom is octahedrally coordinated to the oxo anion, three Cl atoms and two P atoms from the dppp ligand. The six-membered ring formed by the bidentate dppp ligand and the rhenium metal centre is in a chair conformation. The title compound is an intermediate in the synthesis of bis(dppp) complexes of rhenium.

Crystallography, X-Ray↗
PubMed2000

[Soluble Fas in acute rejection in patients with liver transplantation. Response to treatment].

UNLABELLED: It has been suggested that in the cellular rejection of hepatic graft, the lesion provoked by cytotoxic T-lymphocytes might be mediated by the Fas antigen/Fas ligand system, producing cell death by apoptosis. AIM: To determine whether soluble Fas (sFas) is increased during treatment and to evaluate response to treatment. MATERIAL AND METHODS: Fourteen patients with orthotopic liver transplantation who presented an episode of acute cellular rejection were studied. Serum levels of sFas were detected by enzyme-immunoanalysis at diagnosis and again 5 days after treatment was completed. As control groups, sFas was analyzed in 12 patients with liver transplantation without rejection and in 10 healthy subjects. RESULTS: sFas levels were found to be significantly higher in patients with rejection than in those without rejection and in healthy subjects (24.2 +/- 39.1 vs. 2.8 +/- 4.0 vs. 0.6 +/- 1.5 UI/ml; p = 0.03). In patients with acute cellular rejection, immunosuppressive treatment significantly decreased sFas levels compared with basal values (24.2 +/- 39.1 vs. 9.9 +/- 30.2 UI/ml; p = 0.005). A clear correlation between the serum levels of sFas, glutamate oxaloacetate transaminase (GOT), glutamate-pyruvate transaminase/glutamic-pyruvic transaminase (GPT) and gamma-glutamyl transferase (GGT). CONCLUSIONS: a) The increase of sFas during rejection and the decrease in patients with a good evolution suggests that the Fas system may play an important role in the hepatocyte lesion produced by an apoptosis mechanism in these patients. b) Monitoring sFas could be useful in diagnosing rejection and in evaluating response to treatment.

Acute Disease↗
PubMed1999

Severe clinical course of de novo hepatitis B infection after liver transplantation.

The aim of this study is to determine the origin, clinical outcome, allograft histological characteristics, and virological outcome of de novo hepatitis B virus (HBV) infection after orthotopic liver transplantation (OLT). We studied 136 hepatitis B surface antigen (HBsAg)-negative liver transplant recipients. HBV DNA was detected by dot-blot hybridization and polymerase chain reaction (PCR). The S gene was sequenced. Hepatitis C virus (HCV) RNA was assessed by PCR. The long-term clinical and histological outcome was determined. Six of 136 HBsAg-negative patients (4.4%) became HBsAg positive after transplantation. The source of HBV infection was reactivation of latent HBV infection in 2 patients and was not identified in 4 patients. Two donors had isolated core antibody. Two of these 6 patients developed acute liver failure related to hepatitis B. The 4 other patients had severe chronic hepatitis related to hepatitis B. All patients had high-level HBV replication. No significant mutations in the S gene were found. These data suggest that de novo hepatitis B infection is not a mild disease and might represent a significant cause of graft dysfunction. This is the first report of fulminant hepatitis caused by de novo hepatitis B infection after OLT.

Female↗
PubMed1999

Variceal ligation compared with endoscopic sclerotherapy for variceal hemorrhage: prospective randomized trial.

BACKGROUND: To evaluate the safety and efficiency of variceal ligation compared with endoscopic sclerotherapy, 88 patients with cirrhosis with recent variceal bleeding were randomized to undergo either treatment. METHODS: Sclerotherapy was performed using ethanolamine and polidocanol injection at 1, 2, and 3 weeks and every 3 weeks thereafter. The Stiegmann-Goff device was used for variceal ligation at the same intervals. RESULTS: The rate of variceal eradication was the same for both groups, but eradication was accomplished sooner in patients undergoing variceal ligation (5.3+/-1.6 vs. 6.6+/-2.4 endoscopic sessions, p < 0.05) and with fewer complications (19 vs. 6, p < 0.005). The rate of recurrent bleeding was lower in patients treated by ligation (31% vs. 50%, p < 0.05). After eradication, variceal recurrence was more frequent in patients treated by variceal ligation at 1 and 3 years (47% and 92% vs. 23% and 55%, p < 0.01). Portal hypertensive gastropathy was significantly worse in the patients who had variceal ligation (17 patients vs. 6, p < 0.01). Survival and treatment failure were similar in both groups. CONCLUSIONS: Variceal ligation was superior to sclerotherapy in terms of the rate of recurrent bleeding and the occurrence of complications but worse with respect to recurrence of varices and the evolution of portal hypertensive gastropathy. Long-term follow-up studies are required to find out whether there are deleterious effects of variceal ligation.

Esophageal and Gastric Varices↗
PubMed1999

Granulocyte elastase in cirrhotic patients with spontaneous bacterial peritonitis.

Granulocyte elastase (GE) is a powerful proteolytic enzyme that is released by PMNs when degranulated in infectious processes. The aim of this study was to measure GE in ascites and plasma of cirrhotic patients with spontaneous bacterial peritonitis (SBP). We studied 29 cirrhotic patients, 17 of them having SBP (group A). Twelve patients with noninfected ascites formed the control group (group B). At the time of diagnosis of SBP, GE levels in ascites (183.17 +/- 86.11 microg/liter) and plasma (114.6 +/- 35.99 microg/liter) were higher in group A than in group B (27.41 +/- 11.54 microg/liter, P < 0.00001 and 82.54 +/- 20.52 microg/liter, P = 0.01, respectively). Levels of GE in ascites had a high value for discriminating between patients with and without SBP. In the patients who responded to the initial antibiotic treatment, these values significantly decreased in ascites (67.69 +/- 54.22 microg/liter, P = 0.003) and plasma (67 +/- 22.39 microg/liter, P = 0.01) 48 hr after therapy was started, in parallel with the decrease of PMN in ascites. In patients who did not respond, the production of GE remained elevated. Patients who developed renal insufficiency following SBP had more marked elevation of GE in plasma (144.8 +/- 33.43 microg/liter) than those with normal renal function (99.5 +/- 27.53 microg/liter, P = 0.02). These results suggest that the measurement of GE may be helpful for the diagnosis of SBP in patients with cirrhosis and for assessing the efficacy of therapy. In addition, the release of GE into plasma may contribute to the impairment of renal function that follows SBP in some patients.

Ascites↗
PubMed1999

Ability of a cocoa product to correct chronic Mg deficiency in rats.

Epidemiological studies have reported that Western diets are often deficient in Mg. We investigated the ability of a cocoa-derived product, used in some European countries as a dietary complement added to milk, to aid recovery from chronic Mg deficiency in rats. The animals were divided into three groups, each of which received a different amount of dietary Mg. Rats in the Mg-deficient (D) group received an Mg-deficient diet (0.225 g Mg/kg food) during 8 weeks. In the cocoa-supplement group (D + CC), the rats consumed the Mg-deficient diet for 5 weeks, and were then switched for 3 further weeks to the same diet supplemented with 3% (wt/wt) cocoa product, so that the Mg content of the diet was 0.27 g/kg food. Rats in the control group (C) were given the same diet as in group D, except that the amount of Mg was 0.56 g Mg/kg food. We measured the concentration of Mg, Ca and P from ten rats in plasma, whole blood, skeletal muscle, heart, kidney and femur in rats that were fed the diets for 35, 42, 49 or 56 days. In animal fed the cocoa-supplemented diet (D + CC) significant improvements were found between days 35 and 56 in the alterations in Mg, Ca and P caused by Mg deficiency in all tissues studied. On day 56, kidney and bone concentrations of Mg and Ca had returned to normal. Our findings show that the habitual use of the cocoa product as a dietary supplement favors correction of the negative effects of long-term feeding with a diet moderately deficient in Mg.

Animals↗
PubMed1999

Hepatitis G virus infection as a possible causative agent of community-acquired hepatitis and associated aplastic anaemia.

Aplastic anaemia complicating hepatitis is a rare but well-documented phenomenon; however in many patients the cause remains unknown. We present a 24-year-old man with a well-defined community-acquired hepatitis, probably due to hepatitis G virus (HGV), who developed severe aplastic anaemia. In this case, the absence of other agents likely to cause the clinical manifestations, and the detection of HGV RNA at the time of illness, clearly point to this agent as being responsible for both the hepatitis and the aplastic anaemia. Further studies in serial serum samples and meticulous evaluation of the disorders associated with the infection will be needed to prove or dispute a causal association of HGV and aplastic anaemia.

Adult↗
PubMed1999

Cleaning and disinfection of gastrointestinal endoscopes. Comparative analysis of two disinfectants.

UNLABELLED: Gastrointestinal endoscopy can lead to infectious complications, and endoscopes must be disinfected to prevent them. AIM: to evaluate three methods of disinfection: 1) usual cleaning technique and immersion in glutaraldehyde phenolate (GP); 2) meticulous cleaning and immersion in GP, and 3) meticulous cleaning and immersion in hydrogen peroxide. METHOD: thirty endoscopes (15 gastroscopes and 15 colonoscopes) were disinfected with each method. Samples were taken following endoscopic exploration, after cleaning and after disinfection, and were cultured. The number of positive culture (cfu/ml > 1) was counted. RESULTS: the rate of contamination of endoscopes did not decrease significantly after cleaning with method 1 (66 vs 60%), but did decrease with method 2 (38 vs 16%) and method 3 (53 vs 17%). The contamination rate after cleaning was significantly lower with methods 2 and 3 (p < 0.005). This rate was also lower after disinfection (p < 0.025). Method 3 achieved 0% contamination following disinfection. CONCLUSIONS: the greatest decrease in contamination rate was achieved with conscientious cleaning followed by disinfection. Both disinfectants yielded similar results, although hydrogen peroxide produced a higher level of disinfection.

Anti-Infective Agents, Local↗
PubMed1998

Evaluation of carnitine nutritional status in full-term newborn infants.

Carnitine supplements may be advisable not only in premature but also in artificially-fed full-term babies. The acyl-carnitine/free carnitine (AC/FC) and FC/total carnitine (FC/TC) ratios have been considered markers of "carnitine insufficiency" and "carnitine deficiency", respectively. Values of AC/FC>0.40 are considered abnormal and mean that FC has a low bioavailability to the cells and so reflects a "carnitine insufficiency". Values of FC/TC<0.7 indicate "carnitine deficiency". We analyze the validity of such ratios and the limits for them in three groups of full-term neonates (n=66): 22 breast-fed (BF), 22 with formula (F); and 22 fed with carnitine-supplemented formula. Several studies have shown the need to give supplements of carnitine to the neonate because of its "essentiality", but no one has demonstrated the adequate dosages. We therefore propose to establish new limit levels for these ratios to control carnitine nutritional status in neonates, based on the control of percentile ranges for normal BF infants (in this study: 97th percentile of AC/FC>0.83; 3rd percentile of FC/TC<0.54) and on evaluating the needs of neonates and dosages required to supplement F. The supplement of 2.2 mg of L-carnitine/100 ml in the cow's milk formula used in the present study produces a similar biochemical pattern of plasma carnitine and ACs to that observed in BF infants, together with a lower risk of developing "carnitine deficiency" or "carnitine insufficiency" than those babies fed with nonenriched F. Considering that human milk is the best source of nutrition for full-term infants, the limit established for AC/FC and FC/TC ratios at other ages of life seems to be "inadequate" for neonates.

Carnitine↗