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Biomedical subjects

S López

Publications and source records attributed to S López.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Autoimmune hepatitis in children. Initial presentation as fulminant hepatic failure].

UNLABELLED: There are few cases reported of autoimmune hepatitis (AIH) type 2 presenting as fulminant hepatic failure (FHF) in children. The purpose of this study was to report three girls with AIH type 2 that presented as FHF. METHODS: Over a period of 12 years, 123 patients with AIH diagnosed based on international criteria, 9 (7%) were type 2.3 of them presented as FHF. Other etiologies (viral, metabolic and toxic) were ruled out. The treatment was started with prednisone (2 mg-kg-day) and azathioprine (2 mg-kg-day). EVOLUTION: Patients 1 and 3 died while waiting for liver transplant (LT) at 72 and 48 hours after initiating medical treatment. Patient 2 underwent LT3 days after starting treatment, with excellent evolution at 3 years and 7 months of follow up. CONCLUSIONS: 1--AIH type 2 was very infrequent in our group. 2--33% of cases had initial presentation as FHF. 3--The course of the disease was aggressive, not responding to immunosuppressive therapy. The evolution was unfavorable in all patients. 4--LT is an alternative treatment for this severe disease.

Adolescent↗
PubMed1999

Entry of rotaviruses is a multistep process.

The infection of epithelial cells by some animal rotavirus strains requires the presence of sialic acid (SA) on the cell surface. Recently, we isolated rhesus rotavirus variants, named nar, whose infectivity, like that of human rotaviruses, is not dependent on SA. In this work, we have determined the binding properties of these SA-dependent and -independent rotavirus strains to MA104 cells. The half-time of attachment of the SA-dependent porcine rotavirus YM and reassortant virus DS1xRRV was found to be about 10 times longer in neuraminidase-treated cells than in untreated cells. On the other hand, human rotaviruses Wa and DS1, and the variant nar3, bound to cells two to three times more rapidly in the absence of SA. To investigate whether the SA-independent cellular structure recognized by the variant and human rotaviruses was the same, we used an infection assay designed to detect competition for cell surface molecules at both attachment and post-attachment steps. In this assay, human rotavirus Wa efficiently competed the infectivity of YM in untreated cells and that of the variant nar3 in untreated, as well as neuraminidase-treated, cells. This competition was nonreciprocal, since YM and nar3 did not compete, but rather increased three- to fivefold the infectivity of Wa. In contrast, a two-direction competition between the variant nar3 and DS1xRRV was found. Similar results were obtained when psoralen-inactivated viruses were used as competitors, indicating that the competition observed was during the early stages of infection. Altogether, these results suggest the existence of multiple interactions between rotaviruses and the cell surface and revealed the existence of common steps during the entry of human and animal rotavirus strains.

Adsorption↗
PubMed1999

Parasitized female guppies do not prefer showy males.

In many species male sexual characteristics are known to be affected negatively by parasites, which render their hosts unattractive to females, but how parasites affect the mating decisions of their female hosts has received little attention. The monogenean parasite Gyrodactylus turnbulli reduces the sexual display and colour intensity of male guppies, Poecilia reticulata, which makes them less attractive to females. Here, I examine how these parasites affect the mate choice behaviour of their female hosts. Virgin females were experimentally exposed to G. turnbulli and allowed to choose between an attractive and an unattractive male in a simultaneous choice test. Infected females were significantly less discriminatory than healthy ones and their level of activity during choice trials was reduced with increasing parasite load, suggesting an energetic constraint imposed by the parasites. This result implies that sexual selection pressure for male showiness is diminished, which is consistent with recent theoretical models. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Characterization of von Willebrand factor in primary pulmonary hypertension.

The aim of this study was to determine the value of von Willebrand factor (vWF), a well-characterized endothelial cell protein secretion, as a marker for prognosis in patients with primary pulmonary hypertension (PPH). Venous and arterial blood samples were obtained from 18 clinically diagnosed PPH patients and 12 case controls matched for age and sex. Plasma vWF antigen was determined by enzyme-linked immunosorbent assay (ELISA). The patients' multimeric vWF pattern was analyzed by sodium dodecylsulfate (SDS)-agarose-acrylamide electrophoresis, Western blot, and densitometric analysis. vWF sialic acid content was determined by a lectin-based ELISA. The PPH patients showed a higher content of vWF antigen in venous (P = 0.0026) and arterial (P = 0.0094) blood samples than controls. The mean vWF sialic acid content of the PPH patients corresponded to 37.7% of the mean value for the control group. On the basis of the hemodynamic response to vasodilator trial, the PPH patients were grouped as responders or nonresponders. The latter group showed a significantly higher plasma vWF antigen antecubital vein/radial artery ratio, an increased number of unusually large vWF multimers, and a diminished content of vWF sialic acid in comparison with the first group. We believe that our results establish the nature of vWF alterations that are related to endothelial cell damage in patients with primary pulmonary hypertension and that this could be of value when establishing the prognosis in this group of patients.

Adrenergic beta-Agonists↗
PubMed1999

Expression of E-selectin, P-selectin, and intercellular adhesion molecule-1 during experimental murine listeriosis.

The expression of adhesion molecules E-selectin, P-selectin, and intercellular adhesion molecule-1 (ICAM-1) was immunohistochemically investigated during the course of experimental murine listeriosis. Infection was monitored by microbiological count of blood, liver, and spleen. After an early generalized expression of P-selectin and ICAM-1, a later regulation occurred specifically to areas of inflammation. Expression of E-selectin was faint and inconstantly detected in all of the studied organs. In the liver, typical lesions of murine listeriosis were related to the expression of ICAM-1 on sinusoidal endothelial cells and the biliary system and to the de novo expression of P-selectin in hepatic portal vessels. Inflammation in the spleen was related to the expression of ICAM-1 on red pulp sinusoidal cells, especially in the marginal sinus. High endothelial venules of inflamed lymph nodes also expressed P-selectin and ICAM-1. Lesions in the central nervous system appeared on day 3 after infection as a pyogranulomatous leptomeningitis associated with an intense expression of P-selectin and ICAM-1 in meningeal vessels, especially those in the hippocampal sulcus, suggesting a way through which inflammation initially reach the central nervous system during experimental murine listeriosis. Leptomeningitis was followed by the presence of ventriculitis, which was related to the up-regulation of ICAM-1 on choroid plexus epithelial cells, periventricular vessels and ependymal cells. Up-regulation of P-selectin and ICAM-1 during experimental murine listeriosis could play an important role in the recruitment of leukocytes, especially to the liver, lymphoid organs, and central nervous system.

Animals↗
PubMed1999

[The publication of cardiology books in Spain. A bibliometric approach].

INTRODUCTION AND OBJECTIVES: We analyze Spanish production of cardiology books published in Spain and put together in the database ISBN between 1988 and 1997. MATERIAL AND METHODS: For every book various things are considered: author, year of publication, ISBN classification, language, place published and publishers were analyzed. RESULTS: There are 565 books analyzed which are classified in the database under 27 different classes. The principal class is "General pathology. Clinical Medicine. Therapeutics", with 346 books. The places in which most books were published was Barcelona (46.90%) and Madrid (38.41%). The publishing houses were the ones which published more books (64.07%). 79.46 per cent of the books were originally written in Spanish, with at 20.54 per cent which were translated into by other languages. The ones that were translated were principally English (78.45%) and German (14.66%). CONCLUSIONS: These results confirm the tendency observed in other projects and indicate the increase of Spanish publications on cardiology, this is observed over the years. Although, in the years 1996 and 1997 we observe a slight decrease, that we will have to continue analysing with posterior studies to this one; to see if it is an isolated fact or a tendency to the diminution of the production of books published in our country, as a consequence of the evolution of works in other type of supports.

Bibliometrics↗
PubMed1999

Repeated oral dosing with Listeria monocytogenes in mice as a model of central nervous system listeriosis in man.

Human listeriosis is a food-borne disease of immunosuppressed or previously healthy adults. The repeated oral administration of a sublethal dose (5x10(9)colony-forming units) of Listeria monocytogenes for 7 or 10 consecutive days led to the development of severe central nervous system (CNS) lesions in 25% of experimental mice. Histopathological examination of the brain revealed rhombencephalitis and ventriculitis as two distinct inflammatory patterns, resembling those seen in human listeriosis. This model would seem to be potentially useful for research on pathogenesis, predisposing factors and therapy in CNS listeriosis in man. 1999 W.B. Saunders and Company Ltd.

Administration, Oral↗
PubMed1999

Integrated maternal and infant health care in the postpartum period in a poor neighborhood in Santiago, Chile.

An integrated postpartum health-care program was established by the Consultorio San Luis de Huechuraba (CSLH), a nongovernmental organization in a neighborhood of extreme poverty in Santiago, Chile. The main components were education, maternal and infant health care, support for the mothers, and active participation of women from the community served. The program was evaluated through indicators of contraceptive use, breastfeeding performance, infant growth and health, and a qualitative assessment of women's satisfaction. Controls were women of similar characteristics attending the nearby public clinic. Acceptability of contraceptive methods was similar but contraceptive options differed between clinics. The total number of pregnancies and of respondents lost to follow-up was significantly higher for the public clinic than for the CSLH. Breastfeeding duration was significantly longer and infant growth and health were found to be significantly better at the CSLH than at the public clinic. Women valued being treated with respect, receiving education and support, and being offered timesaving services and wider contraceptive choices at the CSLH. This study demonstrates that such interventions are possible for poor communities, providing significant advantages for women and children.

Adult↗
PubMed1999

Correcting the calculation of extent of degradation to account for particulate matter loss at zero time when applying the polyester bag method.

The established calculation of ruminal extent of degradation using the polyester bag method overestimates extent. The wash fraction, at least in part, is subject to losses from the rumen due to passage. Four formulae are proposed to minimize this risk of overestimation. Four options are considered: 1) passage losses for particulate matter escaping from the bag at zero time are according to the particulate fractional passage rate, 2) the liquid rate, and 3) the average of the two, and additionally 4) there is no instantly degradable fraction. The established and proposed formulae were examined using polyester bag data for six forages: grass silage, fresh ryegrass, fresh white clover, alfalfa hay, mixed grasses hay, and hay from a permanent mountain meadow. The established formula gave appreciably higher estimates of extent of degradation in all cases. Overestimation was at least 6.9, 4.9, 2.9, 2.1, 2.4, and 4.5%, respectively, for the six forages.

Animal Feed↗
PubMed1999

Comparison of mathematical models to describe disappearance curves obtained using the polyester bag technique for incubating feeds in the rumen.

Different nonlinear models were evaluated as candidates to describe ruminal degradation kinetics of forages from data obtained by the incubation of the feeds in the rumen using polyester bags. Nine models were used: segmented model with three straight lines (Mod0); simple Mitscherlich or exponential (Mod1); inverse polynomial (Mod2); compartmental model with two exponential terms (Mod3); generalized Mitscherlich (Mod4); generalized Michaelis-Menten (Mod5); logistic (Mod6); Gompertz (Mod7); and generalized Von Bertalanffy (Mod8). All these models can be represented in the general form D = W + S0 x phi(t), where D is in situ disappearance at incubation time t, W and S0 are positive scalars, and phi is a positive monotonically increasing function unique to each of the models studied. Based on first principles, a general formula for calculating the extent of degradation of feeds in the rumen has been derived that is applicable to all the models. The disappearance curves of different feed components (DM, N, and NDF) of 87 Mediterranean forages (i.e., a total of 261 curves) were fitted to all the models. A comparative study was carried out based on the mathematical, statistical, and biological characteristics of the models. Flexible models that can accommodate both diminishing returns and sigmoidal behavior were more appropriate in describing the curves. A discrete-lag parameter was introduced into Mod0, Mod1, and Mod2 to describe the initial stage of the disappearance curve, and this parameter considerably improved the fit of experimental data. Based on statistical criteria, models Mod1, Mod4, Mod5, and Mod8 were better than the others for most statistical tests and disappearance curves, but differences among these four models were not consistent. The estimates of degradation parameters to quantify the rate (half-life, fractional degradation rate), and extent (undegradable fraction, effective degradability) of ruminal degradation of feeds were also used as a means to discriminate between models, although in most cases all of the models gave similar values of the degradation parameters. In particular, when the extent of degradation was calculated for each forage and feed component, differences between the estimates obtained with the different models were of little nutritional significance for the animal.

Animal Feed↗
PubMed1999

Influence of sodium fumarate addition on rumen fermentation in vitro.

The influence of sodium fumarate on rumen fermentation was investigated in vitro using batch and semi-continuous cultures of mixed rumen micro-organisms taken from three sheep receiving a basal diet of hay, barley, molasses, fish meal and a mineral-vitamin supplement (500, 299.5, 100, 91 and 9.5 g/kg DM respectively). Batch cultures consisted of 10 ml strained rumen fluid in 40 ml anaerobic buffer containing 200 mg of the same feed given to the sheep. Sodium fumarate was added to achieve a final concentration of 0, 5 or 10 mmol/l, as a result of the addition of 0, 250 or 500 mumol, equivalent to 0, 200 and 400 g/kg feed. CH4 production at 24 h (360 mumol in the control cultures) fell (P < 0.05) by 18 and 22 mumol respectively (SED 7.5). Total gas production was increased by the addition of fumarate without significant accumulation of H2. Substantial increases in acetate production (92 and 194 mumol; SED 26.7, P < 0.01) were accompanied by increases in propionate formation (212 and 396 mumol; SED 13.0, P < 0.001). Longer-term effects of fumarate supplementation on ruminal fermentation and CH4 production were investigated using the rumen simulation technique (Rusitec). Eight vessels were given 20 g basal diet/d, and half of them received a supplement of fumarate (disodium salt) over a period of 19 d. The response to the daily addition of 6.25 mmol sodium fumarate was a decrease in CH4 production of 1.2 mmol (SED 0.39, P < 0.05), equivalent to the consumption of 4.8 mmol H2, and an increase in propionate production of 4.9 mmol (from 10.4 to 15.3 (SED 1.05) mmol/d, P < 0.01). The inhibition of CH4 production did not decline during the period of time that fumarate was added to the vessels. Thus, the decrease in CH4 corresponded well to the fraction of the fumarate that was converted to propionate. Fumarate had no significant (P > 0.05) effect on total bacterial numbers or on the number of methanogenic archaea, but numbers of cellulolytic bacteria were increased (8.8 v. 23.9 (SED 2.49) x 10(5) per ml, P < 0.01). Fumarate also increased DM digestibility of the basal diet after 48 h incubation (0.476 v. 0.508 (SED 0.0123), P < 0.05). Thus, it was concluded that sodium fumarate may be a useful dietary additive for ruminants, because it diverts some H2 from CH4 production and because it is able to stimulate proliferation of cellulolytic bacteria and digestion of fibre.

Acetates↗
PubMed1999

[Administration of propofol. Addition of lidocaine eases the pain].

This article corresponds to the final paper accepted as passing as a requirement to accede to the level of 500 hours in the "IDER" Masters program "Methodology of Research and Investigation in Healthcare" as part of a correspondence course designed by the University of Alcalá with backing from the University of Antioquía in Colombia. The pain which occurs as a response to an intravenous injection of Propofol is one of the main obstacles to its use as an anesthetic. The wide range of uses of propofol increases the desire to minimize this inconvenience. This study compares the occurrences of pain and the injection of propofol in three groups: the first group was administered propofol without any additives; the second group was administered propofol along with 20 mg of lidocaine; the third group had 40 mg of lidocaine added to the calculated doses of propofol. This study concluded that the addition of lidocaine significantly reduced the pain felt in the circulatory tract selected for the injection of propofol. Administering 20 or 40 mg of lidocaine did not produce any differences in the analgesic effect of this anesthetic.

Adolescent↗
PubMed1998

S100alpha and S100beta proteins in human cutaneous sensory corpuscles: effects of nerve and spinal cord injury.

S100 protein in the vertebrate peripheral nervous system consists of homo- or heterodimers of S100alpha and S100beta proteins, the first predominating in neurons and the second in glial cells. Recently, however, occurrence of S100beta protein in neurons has been reported. The expression of S100 protein by Schwann cells, as well as their derivatives in sensory corpuscles, depends on the sensory axon (i.e., the Schwann cell-axon contact). The present study analyzed the distribution of S100alpha and S100beta proteins in human cutaneous sensory corpuscles and the effects of peripheral or central sensory axon severance in the expression of these proteins. Simple or double immunohistochemistry was carried out using a panel of antibodies against S100alpha, S100beta or S100alpha+beta proteins, and the sections were examined by light or laser confocal scanning microscopy. Skin samples were obtained from normal subjects and patients with spinal cord injury, nerve entrapment, and nerve sections plus graft. The lamellar cells of Meissner corpuscles as well as the inner-core lamellae of the Pacinian corpuscles displayed strong immunoreactivity (IR) for all antigens examined, the most intense labeling being obtained for S100beta protein. The pattern of immunostaining was unchanged after spinal cord injury, whereas the number of stained corpuscles as well as the intensity of IR for each antigen decreased in cutaneous sensory corpuscles after nerve injury, both entrapment and section plus graft. No evidence was found of axonal labeling. The present results provide evidence that Schwann-related cells in human cutaneous sensory corpuscles contain both S100alpha and S100beta and that the expression of these proteins is dependent on the functional and structural integrity of sensory fibers.

Adult↗
PubMed1998

Efficacy of PdB in preventing intraoperative risk of infectious diseases.

The objectives of this study were to (1) determine the number of punctures surgeons and assistants suffer during operations involving a laparotomy during the intraabdominal and closure phases; and (2) determine if the number of puncture injuries during wound closure can be reduced using a new surgical instrument (PdB) that protects the surgeon's hands and the patient's viscera against needlesticks. For the first objective, all laparotomies performed during 1 month (n = 52) were controlled, collecting the gloves used and determining the number of perforations. For the second objective, a randomized prospective controlled study, involving two series of 100 medial laparotomies, was carried out. The incidence of perforations was 29% during the intraabdominal phase and 16% during the wound closure phase. The glove perforation rate while closing medial laparotomies was 31.5% if the PdB was not used and 3% if the PdB was used (p < 0.0001). The glove perforation rate during laparotomy is significant, but with the use of the PdB this incidence can be significantly reduced.

Abdominal Muscles↗
PubMed1998

In vivo interactions among rotavirus nonstructural proteins.

The rotavirus genome encodes six nonstructural (NS) proteins, five of which (NSP1, NSP2, NSP3, NSP5, and NSP6) have been suggested to be involved in a variety of events, such as genome replication, regulation of gene expression, and gene assortment. These NS proteins have been found to be associated with replication complexes that are precursors of the viral core, however, little information is available about the intermolecular interactions that may exist among them. Using the yeast two-hybrid system, which allows the detection of protein-protein interactions in vivo, all possible combinations among the rotavirus NS proteins were tested, and several interactions were observed. NSP1 interacted with the other four proteins tested; NSP3 associated with itself; and NSP5 was found to form homodimers and to interact with NSP6. Co-immunoprecipitation of proteins from rotavirus-infected cells, using hyperimmune sera monospecific for the NS proteins, showed the same interactions for NSP1 as those observed in yeast. Immunofluorescence co-localization analysis of virus-infected epithelial cells revealed that the intracellular distribution of proteins that were seen to interact in yeast had patterns of distribution that would allow such intermolecular interactions to occur. These findings should contribute to the understanding of the role these proteins play in different aspects of the virus replication cycle.

Chromosome Mapping↗
PubMed1998

[Descriptive study of complications caused by mediastinoscopy].

To analyze the surgical and non surgical complications of mediastinoscopy in a series of 200 consecutive patients. Retrospective study of all surgical patients between 1 January 1994 and 1 May 1997. Any complication presenting between time of surgery and patient release is analyzed. Complications were seen in 8 out of 200 cases (4%). In three cases, there were lesions in neighboring structures (recurrent nerve, bronchial artery and innominate artery). The rest were non surgical complications (3 cases of arrhythmia, 2 of prolonged mechanical ventilation). One male patient (0.5%) died from cerebral infarction, probably as a result of arterial occlusion needed to suture damage to the innominate artery. Superior win cava syndrome affected 20% (1 in 5) and morbidity was 60% (3 in 5). Morbidity involving both medical and surgical complications in this series is higher than that reported elsewhere in the literature, in series for which non surgical complications go unreported.

Aged↗