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Biomedical subjects

E Moreno

Publications and source records attributed to E Moreno.

At least 145 records · Page 8Linked to original sources
PubMed1995

The low-affinity component of the glucose transport system in Saccharomyces cerevisiae is not due to passive diffusion.

It has been claimed that the low-affinity component of glucose transport in Saccharomyces cerevisiae is due to passive diffusion of the sugar across the plasma membrane. We have investigated this possibility. For this purpose we have measured the permeability coefficient of hexoses in this organism. We have found that this coefficient is at least two to three orders of magnitude lower than required to account for the low-affinity component of glucose transport, and have concluded that this component is not due to passive diffusion.

Biological Transport↗
PubMed1995

Calcitonin and bisphosphonates treatment in bone loss after liver transplantation.

Osteopenia is a major complication of orthotopic liver transplantation (OLT). However, no effective therapy for bone disease has been defined. We have studied vertebral bone mineral density (VMD) and fasting serum markers of bone formation [bone gla protein (BGP), procollagen I carboxyterminal peptide (PICP)] and metabolism (serum Ca, P, intact parathyroid hormone (iPTH), 25OHD3 and 1,25(OH)2D3) in 120 patents after OLT. VMD was measured by dual-energy X-ray absorptiometry (DXA) using a Hologic QDR 1000 densitometer on two occasions, 12 months apart. Patients with OLT had a VBD significantly lower compared with age- and sexed-matched Spanish controls (P < 0.05). Prevalence of osteoporosis (Z score below -2 SD) was 35.8%. Serum BGP (8.6 +/- 0.7 ng/ml) and PICP (222.9 +/- 81.9 ng/dl) were higher than those of controls. However, serum calcium, phosphorus, iPTH, 25OHD3, and 1,25(OH)2D3 were within normal range. Patients with osteoporosis were randomly treated with 40 IU/day of calcitonin i.m. (Diatin, Ferrer Int. Laboratories) (n = 17) or 400 mg p.o., 15 days every 3 months, of sodium ethiodronate (Difosfen, Rubio Laboratories) (n = 23). All patients received 500 mg/12 hours of elemental calcium p.o. After 12 months of treatment, a significant increment of vertebral mineral density (VMD) was observed (6.4% and 8.2%, respectively). Serum BGP and PICP values remained elevated without a difference between the two drugs. Our results indicate that antiresorptive drugs may be of benefit in the high turnover osteoporosis of OLT recipients.

Adult↗
PubMed1995

Liver transplantation in patients with Budd-Chiari syndrome.

Patients with Budd-Chiari syndrome (obstruction of the hepatic veins) and associated hepatic insufficiency may be candidates for orthotopic liver transplantation (OLT). In our series of 405 OLT patients, 3 were transplanted due to Budd-Chiari syndrome (0.7%). The indication for liver transplantation in these patients was severe hepatic insufficiency (chronic in two and acute in the third one). Morphologic study of the obstructions revealed apparently different causes, including thrombi, membranous webs in hepatic veins, and hydatid cyst compression. The surgical technique employed in these transplantations was similar to that for other etiologies. Due to its implications for the future course of OLT, it is important to determine the exact etiology of Budd-Chiari syndrome in the pretransplant period and to treat the patients with early and long-term anticoagulant therapy to avoid syndrome recurrence.

Adolescent↗
PubMed1995

Heterogeneity of Brucella abortus lipopolysaccharides.

This work demonstrates that Brucella lipopolysaccharide (LPS) preparations are a family of related molecules which display heterogeneity not only at the level of the O polysaccharide, but also at the core oligosaccharide and the lipid A. Sodium dodecyl sulphate/polyacrylamide gel electrophoresis and Western blotting showed that LPS from Brucella strains displayed molecular weight and antigenic heterogeneity. Smooth-type LPS (S-LPS) from B. abortus demonstrated three broad high-molecular-weight bands corresponding to S-LPS, and a low-molecular-weight band corresponding to O antigen lacking rough-type LPS (R-LPS). B. abortus R-LPS displayed four bands in increasing proportions as the molecular weight diminished. Immunodetection on high-performance thin-layer chromatography (HPTLC) with monoclonal antibodies (mAb) showed that R-LPS displayed three diffuse bands. HPTLC of O polysaccharide revealed two fast migrating bands recognized by antibodies. Gel chromatography and HPTLC analysis of core oligosaccharides from R-LPS demonstrated molecular weight heterogeneity as well as heterogeneous banding pattern, with no obvious correspondence between the two profiles. Immunodetection of lipid A on HPTLC plates revealed two major and three minor bands. Reactivity with mAbs suggested that regardless of the lipid A heterogeneity the basic structure of lipid A backbone is maintained.

Brucella abortus↗
PubMed1995

Complete disruption of the main pancreatic duct: endoscopic management.

BACKGROUND: Complete disruption of the main pancreatic duct is an unusual event in the course of acute or chronic pancreatitis. Endoscopic management has already proven effective in the treatment of partial ruptures. METHODS: Thirteen patients presented over a 7-year period with acute (9 patients) or chronic (4 patients) pancreatitis complicated by complete disruption of the main pancreatic duct and cyst formation. Endoscopic treatment was attempted in 12. Treatment varied depending on the site of the rupture and accessibility of the pseudocyst and consisted either of transpapillary drainage (3), cystogastrostomy (3), cystoduodenostomy (2), or combined procedures (4) when one of these procedures did not induce significant decrease in collection size. Long-term results were obtained by observing the patients with ultrasound, CT, ERCP, and clinical evaluation. RESULTS: Short-term results were excellent with complete cyst resolution and clinical recovery in all but one patient treated by endoscopy. Two patients had pseudocyst infection successfully treated by drainage and antibiotics. Long-term follow-up was available for 11 patients (mean duration, 30.2 months; range, 12 to 72 months) without relapsing clinical symptoms or pseudocyst. CONCLUSIONS: Endoscopic management is effective and safe for treating patients with complete main pancreatic duct disruption. A double drainage combining transpapillary drainage and cystoenterostomy must be done in selected instances, especially when rupture occurs in the setting of chronic pancreatitis with stricture or stone distal to the rupture.

Acute Disease↗
PubMed1995

Bovine leukaemia-virus infection in Costa Rica.

The geographical distribution of bovine leukaemia-virus (BLV)-infected herds in Costa Rica and the isolation of BLV from cases of enzootic bovine leukosis are presented. It was found that BLV is prevalent throughout the country, affecting mostly dairy cattle (Bos taurus) located in the highlands around the central valley of Costa Rica. By contrast, beef cattle (Bos indicus) raised in the lowlands were affected to a lesser extent. One out of four isolates of BLV obtained from local cattle with lymphosarcomatous tumours was analysed and had similar physical, serological and biological characteristics to a reference strain of BLV isolated in the USA. However, different patterns of recognition of BLV-protein p24 were observed among naturally infected cattle using the western-blotting technique.

Animals↗
PubMed1995

Gingival overgrowth induced by nifedipine and cyclosporin A. Clinical and morphometric study with image analysis.

In this study, we developed a quantitative method with digital image analysis to evaluate the degree of gingival overgrowth (GO), and compared GO in kidney transplant patients treated with cyclosporin A (CsA) (n = 21) or CsA+nifedipine (n = 8) and a group of healthy controls (n = 30). The method was reproducible and reliable. Our findings showed significant differences in papillary and gingival surface between controls and transplant patients treated with GO inducers. Gingival overgrowth index also differed significantly between controls and each patient group (p < 0.01, Kruskal-Wallis test). The administration of the calcium channel blocker nifedipine potentiated the adverse effect of CsA: comparison of the morphometric findings revealed significant differences between patients treated with CsA alone and CsA+nifedipine in papillary area, dental area, and GO index (p < 0.01, Mann-Whitney U-test). We conclude that the method of image analysis we developed is useful in assessing the degree of GO.

Adult↗
PubMed1995

Modification of immune response in mice by ciprofloxacin.

Some studies have suggested that the addition of ciprofloxacin to in vitro cultures of mitogen-stimulated lymphocytes exerts inhibitory effects on cell cycle progression and immunoglobulin (Ig) secretion. We tested the effects of this drug on some immunity parameters in BALB/c mice. Mice treated intraperitoneally with ciprofloxacin (10 mg/kg of body weight per day) for 3 consecutive days and immunized with sheep erythrocytes 24 h after the last injection showed significant suppression of hemolytic IgG-forming cells, whereas the response of IgM-forming cells remained unchanged. When treatment lasted 7 days the response of antibody-forming cells was not modified. When the 3-day treatment was started at 24 h after immunization with sheep erythrocytes, the response of IgM-forming cells was increased, whereas the response of IgG-forming cells was suppressed. Delayed-type hypersensitivity to sheep erythrocytes was significantly suppressed in animals that received the 3-day treatment with ciprofloxacin and were immunized subcutaneously 24 h after the last injection. In vitro proliferation of lymphocytes from ciprofloxacin-treated mice in response to either lipopolysaccharide or concanavalin A was also suppressed. Leukopenia and an increase in the level of granulocyte-macrophage colony-forming cells in bone marrow were also observed in ciprofloxacin-treated mice. These results, together with those from other reports, suggest that modification of the biological responses by ciprofloxacin is a complex phenomenon that may be influenced by several factors.

Animals↗
PubMed1995

The outer membranes of Brucella spp. are resistant to bactericidal cationic peptides.

The actions of polymyxin B, rabbit polymorphonuclear lysosome extracts, 14 polycationic peptides (including defensin NP-2, cecropin P1, lactoferricin B, and active peptides from cationic protein 18 and bactenecin), EDTA, and Tris on Brucella spp. were studied, with other gram-negative bacteria as controls. Brucella spp. were comparatively resistant to all of the agents listed above and bound less polymyxin B, and their outer membranes (OMs) were neither morphologically altered nor permeabilized to lysozyme by polymyxin B concentrations, although both effects were observed for controls. EDTA and peptides increased or accelerated the partition of the hydrophobic probe N-phenyl-naphthylamine into Escherichia coli and Haemophilus influenzae OMs but had no effect on Brucella OMs. Since Brucella and H. influenzae OMs are permeable to hydrophobic compounds (G. Martínez de Tejada and I. Moriyón, J. Bacteriol. 175:5273-5275, 1993), the results show that such unusual permeability is not necessarily related to resistance to polycations. Although rough (R) B. abortus and B. ovis were more resistant than the controls were, there were qualitative and quantitative differences with smooth (S) brucellae; this may explain known host range and virulence differences. Brucella S-lipopolysaccharides (LPSs) had reduced affinities for polycations, and insertion of Brucella and Salmonella montevideo S-LPSs into the OM of a Brucella R-LPS mutant increased and decreased, respectively, its resistance to cationic peptides. The results show that the core lipid A of Brucella LPS plays a major role in polycation resistance and that O-chain density also contributes significantly. It is proposed that the features described above contribute to Brucella resistance to the oxygen-independent systems of phagocytes.

Antimicrobial Cationic Peptides↗
PubMed1995

Histological diagnosis of cytomegalovirus hepatitis in liver allografts.

AIMS--To determine the incidence of histologically documented cytomegalovirus (CMV) hepatitis following orthotopic liver transplantation (OLT) and to assess the effectiveness of immunohistochemistry and in situ hybridisation (ISH) in detecting CMV. To describe the histological pattern most frequently associated with CMV hepatitis in order to select the biopsy group in which these modern techniques are most effective. METHODS--A prospective histological study was carried out on 853 biopsy specimens, obtained from 191 liver allografts (160 patients). Specimens were stained with haematoxylin and eosin and immunohistochemically (avidin-biotin complex) using monoclonal antibodies directed against early and late CMV antigens. A retrospective selection was made of 23 specimens with viral inclusion bodies in cytomegalic cells (group A) to characterise the most frequently associated histological pattern, and of 34 other specimens without viral inclusion bodies (group B) but with the same microscopic features as group A. Re-cuts from both specimen groups were studied using immunohistochemistry and ISH with a CMV specific complementary DNA probe. RESULTS--CMV infection was confirmed in 35 specimens (29 by immunohistochemistry, 23 by presence of inclusion bodies in haematoxylin and eosin stained sections, 16 by ISH) from 27 patients (incidence 16.9%). CMV hepatitis was diagnosed within 46 +/- 19 (range 21-114) days posttransplant. Twenty on (91.3%) of the 23 biopsy specimens with inclusion bodies (group A) displayed heterogeneous inflammatory foci disseminated throughout the hepatic lobule. Nineteen specimens (82.6%) were positive by immunohistochemistry and 14 (60.9%) by ISH. In eight (23.5%) of the 34 group B specimens CMV infection was confirmed by immunohistochemistry (n = 6) or ISH (n = 2). Another 12 (35.3%) of the group B specimens negative on staining with haematoxylin and eosin, immunohistochemistry and ISH came from allografts in which previous or subsequent biopsy specimens were CMV positive. CONCLUSIONS--Demonstration of cytomegalic inclusion bodies in haematoxylin and eosin sections is sufficient for a diagnosis of CMV hepatitis. The routine use of immunohistochemistry in all allograft biopsy specimens in more sensitive than demonstration of inclusion bodies by staining with haematoxylin and eosin but may yield false negative results because of the focal distribution of positive cells. ISH was less sensitive than staining with haematoxylin and eosin and/or immunohistochemistry. A histological picture of "disseminated focal hepatitis" without viral inclusion bodies selects a group of allograft biopsy specimens in which immunohistochemistry and/or ISH may improve detection of CMV.

Biopsy↗
PubMed1995

A clinopathologic review of 8 liver graft primary nonfunctions.

In a group of 276 consecutive liver transplants 8 primary graft nonfunctions were identified (2.9%). Recipients showed a progressive elevation of transferases (mean maximum value ALT: 5000 +/- 1892 U/l) and bilirubin (mean maximum value: 20 +/- 11.8 mg/dl) and a decrease in the percent prothrombin time (mean minimum value 26 +/- 13 min.) in the post-implantation survival time of the 8 grafts (range 1-5 days). No statistically significant differences were observed between mean cold and warm-ischemia times for these 8 donor organs and those of a control group of 92 consecutive grafts. All organs except one were ABO isogroup and all except another one displayed negative lymphocytotoxic crossmatch. Predominantly small-droplet hepatocytic vacuolization with no nuclear displacement was observed in plastic-embedded semithin sections of all post-primary nonfunction liver tissues (severe in 4 grafts, centri-mediozonal in 2, and centrolobular in 2). In 3 cases where fresh liver tissue was available the lipidic nature of the vacuoles was confirmed with electron microscopy and with frozen sections stained with Sudan III. Other microscopic lesions were also observed: spotty monocellular coagulative necroses, variable extension of zonal coagulative necroses and hemorrhages, cholestasis and minor mixed inflammatory infiltrate. Comparative microscopic study of these tissues with the protocol biopsy specimens obtained 2-4 hours after reperfusion demonstrated previous liver cell-vacuolization in only 3 cases. In conclusion, an acute progressive microvascular steatosis developed in this primary nonfunction series. No specific etiopathogenic factors were identified.

Adolescent↗
PubMed1995

[Liver transplantation using grafts from donors over 65].

OBJECTIVE: Donors age 50 years was an exclusion criteria in past decades. The increase of patients in the waiting list has determined the acceptance of older donors (over 65 years old). We analyze our results in liver transplantation using donors over 65 years. PATIENTS: From 1986 to may 1994, we performed 381 OLT. In five cases (1.3%) the OLT was performed using donors over 65 years of age (66, 67, 68, 70 and 71). The selection criteria for donors and recipients were similar to the other transplanted patients. Immunosuppression included cyclosporine or FK-506, prednisone and azathioprine. RESULTS: There were no primary graft failures and preservation damage, biochemical and clinical evolution were not different to the procedures using younger donors. Three grafts presented non-corticoresistant acute rejection. After a follow-up of 11.6 mo (range 4-37 mo) only one graft was lost (Kaposi's sarcoma in the liver). Four grafts and four patients are in excellent biochemical and clinical condition. CONCLUSIONS: Donor age should not be an exclusion criteria. Grafts from older donors (over 65 years old) may be considered safe and will permit to increase the number of OLT.

Adult↗
PubMed1994

Neutralizing interaction between heparins and myotoxin II, a lysine 49 phospholipase A2 from Bothrops asper snake venom. Identification of a heparin-binding and cytolytic toxin region by the use of synthetic peptides and molecular modeling.

Heparin binds to phospholipase A2 myotoxins from Bothrops asper snake venom, inhibiting their toxic activities. This interaction was investigated using purified myotoxin II, a Lys-49 phospholipase A2 of this venom, and a series of heparin variants, fragments, and other glycosaminoglycans. The binding was correlated to toxin neutralization, using endothelial cells as a target. Myotoxin II binds radiolabeled heparin in solution unselectively, and forms macromolecular complexes with an optimum at a heparin:toxin molar ratio of 1:5. Both O-sulfates and N-sulfates play a role in heparin binding, in the order of importance 2-O-sulfates > 6-Osulfates > N-sulfates. The shortest heparin oligosaccharides interacting with myotoxin II are hexasaccharides. The binding of a neutralizing monoclonal antibody (MAb-3) to myotoxin II was not inhibited by heparin, indicating that the two molecules interact with different sites on the toxin. A synthetic peptide (residues 115-129 in the numbering system of Renetseder et al. (Renetseder, R., Brunie, S., Dijkstra, B. W., Drenth, J., and Sigler, P. B. (1985) J. Biol. Chem. 260, 11627-11634) of myotoxin II displays both heparin-binding and cytolytic activities. It is concluded that heparin neutralizes myotoxin II by binding to a strongly cationic site in the region of residues 115-129, a possible contribution of lysines 36 and 38 suggested by molecular modeling studies. As this cationic region appears to be responsible for the cytolytic activity of the toxin, the present report constitutes the first identification of a cytotoxic region on a phospholipase A2 myotoxin.

Amino Acid Sequence↗