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Biomedical subjects

S Sanz

Publications and source records attributed to S Sanz.

At least 19 recordsLinked to original sources
PubMed2005

Expression of insulin-like growth factor I by activated hepatic stellate cells reduces fibrogenesis and enhances regeneration after liver injury.

BACKGROUND/AIM: Hepatic stellate cells (HSCs) express alpha-smooth muscle actin (alphaSMA) and acquire a profibrogenic phenotype upon activation by noxious stimuli. Insulin-like growth I (IGF-I) has been shown to stimulate HSCs proliferation in vitro, but it has been reported to reduce liver damage and fibrogenesis when given to cirrhotic rats. METHODS: The authors used transgenic mice (SMP8-IGF-I) expressing IGF-I under control of alphaSMA promoter to study the influence of IGF-I synthesised by activated HSCs on the recovery from liver injury. RESULTS: The transgene was expressed by HSCs from SMP8-IGF-I mice upon activation in culture and in the livers of these animals after CCl4 challenge. Twenty four hours after administration of CCl4 both transgenic and wild type mice showed similar extensive necrosis and increased levels of serum transaminases. However at 72 hours SMP8-IGF-I mice exhibited lower serum transaminases, reduced hepatic expression of alphaSMA, and improved liver morphology compared with wild type littermates. Remarkably, at this time all eight CCl4 treated wild type mice manifested histological signs of liver necrosis that was severe in six of them, while six out of eight transgenic animals had virtually no necrosis. In SMP8-IGF-I mice robust DNA synthesis occurred earlier than in wild type animals and this was associated with enhanced production of HGF and lower TGFbeta1 mRNA expression in the SMP8-IGF-I group. Moreover, Colalpha1(I) mRNA abundance at 72 hours was reduced in SMP8-IGF-I mice compared with wild type controls. CONCLUSIONS: Targeted overexpression of IGF-I by activated HSCs restricts their activation, attenuates fibrogenesis, and accelerates liver regeneration. These effects appear to be mediated in part by upregulation of HGF and downregulation of TGFbeta1. The data indicate that IGF-I can modulate the cytokine response to liver injury facilitating regeneration and reducing fibrosis.

Actins↗
PubMed2002

Effectiveness of chlorine washing disinfection and effects on the appearance of artichoke and borage.

AIM: Optimal conditions for chlorine application to obtain a reasonable decrease in the microbial counts without damaging the appearance of artichoke and borage have been established. METHODS AND RESULTS: The influence of chlorine concentration (0-200 mg l(-1)), pH, addition of organic acids, contact time and presence of protective structures on the microflora and vegetal appearance were studied. When pH was not controlled the effect of chlorine depended on its concentration until the pH increase caused by addition of chlorine reached 8.8. Any further increase in chlorine concentration was nullified by the pH increase. When pH was adjusted to 4.5 with acetic acid, the effectiveness increased with concentration. However, the use of citric acid to control pH caused a sharp decrease in effectiveness at concentration about 250 mg l(-1). The higher effectiveness of chlorine on homogenized plant extracts compared with the whole plant showed the impact of the vegetal structures on the resistance of the microorganisms. For artichoke, a relationship between the effectiveness of chlorine disinfection and its structures was also found. Extended washing times did not affect the total counts. However, in both vegetables, the appearance was affected by the extended contact times. CONCLUSIONS: The solutions rendering the highest microbial reduction with minimum damages were: 50 mg l(-1) free chlorine without pH control for artichoke and 100 mg l(-1) free chlorine at pH 7.0 for borage. SIGNIFICANCE AND IMPACT OF THE STUDY: Specific conditions for chlorine disinfection of artichoke and borage were determined to reduce the microorganisms in minimally processed artichoke and borage without damaging their appearance.

Acetic Acid↗
PubMed2002

Effect of ursodeoxycholic acid on methionine adenosyltransferase activity and hepatic glutathione metabolism in rats.

BACKGROUND AND AIMS: Both bile salts and glutathione participate in the generation of canalicular bile flow. In this work, we have investigated the effect of different bile salts on hepatic glutathione metabolism. METHODS: Using the isolated and perfused rat liver, we studied hepatic glutathione content, and metabolism and catabolism of this compound in livers perfused with taurocholate, ursodeoxycholate, or deoxycholate. RESULTS: We found that in livers perfused with ursodeoxycholate, levels of glutathione and the activity of methionine adenosyltransferase (an enzyme involved in glutathione biosynthesis) were significantly higher than in livers perfused with other bile salts. In ursodeoxycholate perfused livers, methionine adenosyltransferase showed a predominant tetrameric conformation which is the isoform with highest activity at physiological concentrations of substrate. In contrast, the dimeric form prevailed in livers perfused with taurocholate or deoxycholate. The hepatic activities of gamma-glutamylcysteine synthetase and gamma-glutamyltranspeptidase, enzymes involved, respectively, in biosynthetic and catabolic pathways of glutathione, were not modified by bile salts. CONCLUSIONS: Ursodeoxycholate specifically enhanced methionine adenosyltransferase activity and hepatic glutathione levels. As glutathione is a defensive substance against oxidative cell damage, our observations provide an additional explanation for the known hepatoprotective effects of ursodeoxycholate.

Animals↗
PubMed2001

Behaviour of Listeria monocytogenes in packaged fresh mushrooms (Agaricus bisporus).

AIMS: The aim of this study was to evaluate the potential of Listeria monocytogenes to grow in mushrooms packaged in two different types of PVC films when stored at 4 degrees C and 10 degrees C. METHODS AND RESULTS: Mushrooms were packed in two polymeric films (perforated and nonperforated PVC) and stored at 4 degrees C and 10 degrees C. The carbon dioxide and oxygen content inside the packages, aerobic mesophiles, psychrotrophs, Pseudomonas spp., Listeria monocytogenes, faecal coliforms, Escherichia coli, anaerobic spores and major sensory factors were determined. The mushrooms packaged in nonperforated film and stored at 4 degrees C had the most desirable quality parameters (texture, development stage and absence of moulds). Listeria monocytogenes was able to grow at 4 degrees C and 10 degrees C in inoculated mushrooms packaged in perforated and nonperforated films between 1 and 2 log units during the first 48 h. After 10 d of storage, the populations of L. monocytogenes were higher in mushrooms packaged in nonperforated film and stored at 10 degrees C. CONCLUSIONS: MAP followed by storage at 4 degrees C or 10 degrees C extends the shelf life by maintaining an acceptable appearance, but allows the growth and survival of L. monocytogenes. SIGNIFICANCE AND IMPACT OF THE STUDY: According to this study additional hurdles must be studied in order to prevent the growth of L. monocytogenes.

Agaricus↗
PubMed2000

The effect of a commercial starter culture addition on the ripening of an artisanal goat's cheese (Cameros cheese).

The evolution of physicochemical parameters, and the most important microbial groups, were determined for the following three batches of 'Cameros' goat's milk cheese during ripening: Batch R elaborated with raw milk, Batch RS elaborated with raw milk and with the addition of a starter culture, and Batch PS elaborated with pasteurized milk and with the addition of the same culture. No differences in total solids (TS) or in the content of NaCl, fat and total nitrogen (expressed as percentages of TS) were found during the ripening. The pH, fat acidity and non-protein nitrogen (NPN, expressed as a percentage of TN) showed significant differences between the batches. The inoculated batches showed the fastest drop in pH at the beginning of the ripening period, but the cheeses of Batch R showed a higher degree of lipolysis and proteolysis. The addition of a starter influenced the microbiological quality of the cheeses. Differences in the counts of Enterobacteriaceae and faecal coliforms were found between Batches R and RS after 15 days. Staphylococcus aureus increased in number during the early period of ripening and attained a population above 6 log cfu g-1 in Batch R in the period from 5 to 10 days. However, enterotoxins were not detected in this Batch. Batch R showed lower values of lactic acid bacteria at the beginning of the ripening period, but no significant differences were found between batches in the period from 5 to 15 days of ripening. At the beginning of the ripening, Lactococcus was the main lactic acid bacteria, with L. lactis lactis being predominant. After 15 days, the lactic acid bacteria counts decreased in the three batches, especially in the cheeses of Batch PS (only 2.2 log cfu g-1 was found at 60 days), as lactococci (the only lactic acid bacteria present in Batch PS) are incapable of growing under the conditions found in cheeses at the end of their ripening period. At this time, Lactobacillus was the predominant genus in Batches R and RS, with L. plantarum predominant. No lactococci were found from day 30 in Batch R and from day 40 in Batch RS. The cheeses of Batch RS received the most favourable scores from the tasting panel for all attributes judged: cut appearance, colour, aroma, taste, texture and general acceptance.

Animals↗
PubMed2000

Effect of packaging conditions on the growth of micro-organisms and the quality characteristics of fresh mushrooms (Agaricus bisporus) stored at inadequate temperatures.

Mushrooms were packed in two polymeric films (perforated and non-perforated PVC) and stored at 17 degrees C and 25 degrees C. The carbon dioxide and oxygen content inside the packages, aerobic mesophiles, Pseudomonas spp., faecal coliforms, Escherichia coli, anaerobic spores and major sensory factors (colour, texture, development stage and presence of moulds) were determined. The non-perforated packages had the highest contents of CO2 (6-7%), the lowest contents of O2 (0.013-0.17%) and the most desirable quality parameters (texture, development stage and absence of moulds). Pseudomonas spp. counts were around 1 logarithmic unit lower in mushrooms packaged in non-perforated film as the O2 concentrations were lower than in perforated film. The mushrooms themselves were inoculated with an enterotoxin A-producing strain of Staphylococcus aureus, packaged in overwrapped trays and stored at 17 and 25 degrees C. Staphylococcus aureus did not grow in the samples stored at 17 degrees C. Only slight growth was observed in mushrooms packaged with non-perforated film after 1 day at 25 degrees C. No enterotoxin was detected in any package. Faecal coliform counts were <2 log cfu g(-1). Escherichia coli was not isolated in any of the samples. At 25 degrees C, counts of anaerobic spores of around 2 log cfu g(-1) were detected in those mushrooms packaged in non-perforated film.

Agaricus↗
PubMed1999

In vitro and in vivo study of glutamate dehydrogenase encapsulated into mouse erythrocytes by a hypotonic dialysis procedure.

Glutamate dehydrogenase (GDH) has been encapsulated into mouse erythrocytes by a hypotonic dialysis/isotonic resealing method. Although a low GDH entrapment yield was achieved (3.8%), this percentage appeared sufficient enough to metabolize high quantities of ammonia. Carrier cell recovery yield was 56%. Due to the decrease in cell volume and haemoglobin content, constant mean cell haemoglobin concentration (MCHC) values were obtained. The osmotic fragility curves (OFC) indicated that dialyzed/resealed-RBCs are more resistant to hypotonic haemolysis than native-RBCs. The successful in vitro ammonia degradation by GDH-RBCs was reflected in its total disappearance from the incubation medium at around 48 h. In contrast, initial ammonia levels were not affected during the incubation in the presence of native-RBCs and remained constant. Two different methods were used for the preparation of hyperammonaemic mice model. Since the intraperitoneal (i.p.) administration of ammonium acetate produced high ammonia levels that lasted only a few minutes, the i.p. administration of urease was chosen, given that it generated elevated ammonia levels for longer periods of time. Hyperammonaemic mice quickly removed high levels of circulating ammonia in the presence of GDH-RBCs, whereas in the presence of native-RBCs ammonia was slowly metabolized. These results suggest that loaded GDH-erythrocytes can be used as a potential carrier systems for the in vivo removal of high levels of ammonia from blood.

Ammonia↗
PubMed1998

In vitro study of alcohol dehydrogenase and acetaldehyde dehydrogenase encapsulated into human erythrocytes by an electroporation procedure.

The optimal conditions for electroporated/resealed loading of alcohol dehydrogenase (ADH) and/or acetaldehyde dehydrogenase (ALDH) into human erythrocytes were established prior to the study, with the following characteristics: 300 V, 1 ms pulse time, eight pulses every 15 min and 1 h resealing at 37 degreesC. High encapsulation yield and carrier cell recoveries were achieved. Cell volumes increase while hemoglobin contents decrease; in consequence a decrease in cell hemoglobin concentration was observed. A lower hypotonic resistance of loading erythrocytes (throughout osmotic fragility curves) and unaltered oxygen transport capability (as given by oxygen equilibrium curves) were observed. The stability against time (up to 168 h-7 days) of encapsulated individual enzymes, either ADH- or ALDH-red blood cells (RBCs), was studied at 4 degreesC and 37 degreesC, in comparison with that of free enzyme solutions. Both enzymes were released from carrier RBCs to the incubation medium. The stability of carrier RBCs was studied under similar conditions. Non-significant variations in hematological parameters were observed. However, the hemoglobin derivative forms showed modifications. The continuous degradation of ethanol by ADH-RBCs and coencapsulated ADH- and ALDH-RBCs, as a function of time (up to 70 h) suggests the use of these carrier RBCs as agents for complete metabolization of ethanol. The mentioned properties bare the possibility of using ADH and ALDH as carrier systems in in vivo situations.

Alcohol Dehydrogenase↗
PubMed1998

Identification and characterization of a new gene from human chromosome 21 between markers D21S343 and D21S268 encoding a leucine-rich protein.

We initiated the present work as part of an effort to identify and characterize genes from the EST2-HMG14 region from human chromosome 21 potentially responsible for some of the Down syndrome (DS) features. Genomic sample sequencing with cosmid clone A1047 located in the ETS2-HMG14 region of chromosome 21 has led to the identification and sequencing of a novel 1080-bp cDNA. This cDNA contains a potential ORF of 867 bp predicting a 288-amino-acid protein rich in leucine with a molecular weight of 32.8 kD. Northern blot analysis and RT-PRC indicate that the expression of this novel gene is high in testis and in the human leukemic T cell line Jurkat and lower in other tissues including all fetal tissues studied. We have called to this novel gene c21-LRP (chromosome 21 leucine-rich protein) and, because of its location in the DS-2 region, it could be a candidate for some of the DS anomalies. Mapping experiments have narrowed the location of the c21-LRP gene between markers D21S343 and D21S268 from chromosome 21. Analysis of the c21-LRP protein predicts two transmembrane helices and detects several signatures and potential homologies to known proteins pointing toward several potential roles for this protein.

Amino Acid Sequence↗
PubMed1996

Erythrocytes as carriers for recombinant human erythropoietin.

PURPOSE: The aim of this work was to encapsulate recombinant human erythropoietin (rHuEpo) in human and mouse red blood cells (RBCs) to improve the stability of encapsulated rHuEpo. METHODS: The encapsulation of rHuEpo was achieved by an hypotonic dialysis-isotonic resealing procedure. A radioimmunoassay method was used for the estimation of rHuEpo. The hypoosmotic resistance of carrier erytrhocytes was studied by osmotic fragility measurements. Cell morphology was observed under scanning electron microscopy. Encapsulated rHuEpo was identified by an immunogold labeling assay. RESULTS: Encapsulation yields were 22% for human RBCs and 14% for mouse RBCs. Cell recovery was around 70%. Carrier-RBCs exhibited a tendency to spherocytic morphology, and showed the typical higher hypoosmotic resistance than normal RBCs. The presence of rHuEpo inside carrier RBCs was identified. The stability of encapsulated rHuEpo seems to be related to the experimental conditions used during the encapsulation procedure. An increase with time of released rHuEpo was observed in carrier-RBC suspensions. CONCLUSIONS: The encapsulation of rHuEpo in RBCs has been achieved for the first time. These carrier RBC-preparations may serve as an alternative sustained cell delivery system for the in vivo administration of rHuEpo.

Animals↗
PubMed1995

Circulating adhesion molecules during kidney allograft rejection.

Adhesion molecules appear on leukocytes and endothelial cells mediating the localization and migration of leukocytes to sites of inflammation. Rejecting kidney grafts have shown an increased expression of these molecules. Recent reports have detected in serum soluble forms of adhesion molecules that could play a role in regulating inflammation. We have measured by ELISA the circulating serum levels of ICAM-1, VCAM-1 and E-selectin in: 23 controls, 33 chronic renal failure patients (CRF), 20 hemodialysis patients (HD), 17 samples from 6 patients with stable kidney graft function (STx), 25 samples from 8 patients with steroid-responsive rejection proven by biopsy, and 28 samples from 9 patients with steroid-resistant rejection and good response to OKT3. There was not a rise in cICAM-1 or cE-selectin levels during rejection compared with the steady phase before and after rejection. In the case of cVCAM-1, only the OKT3 group showed increased rejection levels (P < 0.05) that were maintained after rejection. For ICAM-1, CRF and HD groups had higher levels than the remaining groups. cVCAM-1 levels were elevated in all groups when compared with control, furthermore, OKT3 and HD groups had higher levels than the STx, CRF, or steroid-responsive groups. For cE-selectin, we only found differences between the CRF and both rejection groups. Serum creatinine correlated significantly with c-ICAM-1 and cVCAM-1 R = 0.30 and R = 0.22), but not with cE-selectin. We conclude that soluble adhesion molecules levels are not valuable markers for rejection. Patients with chronic renal failure have increased levels of adhesion molecules, which could reflect an impaired elimination.

Antibodies, Monoclonal↗
PubMed1995

Microsurgical penis replantation after self-mutilation.

The microsurgical reattachment of a penis following self-amputation by a psychiatric patient is discussed. This is the 15th case reported in the literature. We have reviewed the previous reports and outline the management of penis amputation. The importance of using microsurgical techniques in order to achieve better functional and cosmetic results is discussed.

Adult↗
PubMed1995

The influence of enzyme concentration on the encapsulation of glutamate dehydrogenase and alcohol dehydrogenase in red blood cells.

Glutamate dehydrogenase (GDH) and alcohol dehydrogenase (ADH) have been encapsulated in sheep and human red blood cells (RBCs) by a hypotonic dialysis/isotonic resealing procedure. At a fixed enzyme level in the dialysis bag (100 units/ml of RBCs), a significant encapsulation yield was observed for ADH, both in human (17.2%) and sheep (47.9%) RBCs, whereas a very low entrapment of GDH was achieved (1-3%) in either species. Carrier cell recovery was 61-65% in humans and 30-34% in sheep. Because of the aggregation of GDH to large polymers at protein levels above 1 mg/ml, the yield of encapsulation and the specific activity in human carrier RBCs were compared at different enzyme concentrations. While entrapment was not affected by differences in ADH up to 13,000 units/ml of RBCs (38 mg/ml), the yield of GDH encapsulation significantly decreased as the enzyme level increased up to 750 units/ml of RBCs (15 mg/ml), thus demonstrating the importance of protein concentration in the encapsulation process for those enzymes that tend to aggregate.

Alcohol Dehydrogenase↗
PubMed1994

Density gradient separation of L-asparaginase-loaded human erythrocytes.

L-Asparaginase has been encapsulated in human red blood cells using a hypotonic dialysis process. Erythrocytes loaded with L-Asparaginase were separated into eight fractions using a discontinuous Percoll density gradient. A minor cell subpopulation of low density cells and a major subpopulation of denser erythrocytes was obtained after hypotonic dialysis treatment, in both the absence or presence of L-Asparaginase. The encapsulated L-Asparaginase activity per resealed erythrocyte was higher in low-density cells and decreased progressively with increasing in cellular density.

Asparaginase↗
PubMed1992

Properties of hypotonized, crosslinked and crosslinked- permeabilized rat erythrocytes as potential carrier systems.

The osmotic fragility curves of isotonic rat RBCs, studied at pH 8 to avoid the Hb insolubility, are similar to those in humans at pH 7.4. Hypotonized rat RBCs, either directly or dialysed (0-24 h), are more hemolysis-resistant than isotonic rat RBCs. The discocyte-stomatocyte-spherocyte transformation can be observed with scanning electron microscopy. Protein crosslinking with dimethyl suberimidate can stabilize RBCs. The crosslinking level (60%), the cellular yield (80%), the mechanical and hemolytic resistance and the protective effect of enzyme activities, were studied in crosslinked or crosslinked- permeabilized RBCs after digitonin treatment. The normal discocytic shape of RBCs under scanning electron microscopy becomes stomatocytic in crosslinked and crosslinked- permeabilized RBCs with an erosioned surface.

Animals↗
PubMed1992

Conformational changes of S-1 related to its dissociation from actin.

The peptide pattern obtained after proteolysis of S-1 with trypsin was different in the absence or presence of anions. The affinity of tryptic and undigested S-1 for anions (CN-, SCN- or HCO3-) was different, as reflected by the altered values of Ki or Ka obtained from ATPase activity measurements. Anions CN-, SCN-, HCO3-, or PPi induced dissociation of actomyosin when added to acto-S-1 or acto-heavy-meromyosin. Among nucleoside di- and triphosphates, only triphosphates were effective with regard to the dissociation. The results suggest the existence of a regulatory site of cationic nature on S-1, which might be involved in the dissociation of actin from myosin.

Actins↗