PubMed Health⌕ Search

Biomedical subjects

S García

Publications and source records attributed to S García.

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

Inositolphosphoglycan mediators structurally related to glycosyl phosphatidylinositol anchors: synthesis, structure and biological activity.

The preparation of the pseudopentasaccharide 1a, an inositol-phosphoglycan (IPG) that contains the conserved linear structure of glycosyl phosphatidylinositol anchors (GPI anchors), was carried out by using a highly convergent 2+3-block synthesis approach which involves imidate and sulfoxide glycosylation reactions. The preferred solution conformation of this structure was determined by using NMR spectroscopy and molecular dynamics simulations prior to carrying out quantitative structure--activity relationship studies in connection with the insulin signalling process. The ability of 1a to stimulate lipogenesis in rat adipocytes as well as to inhibit cAMP dependent protein kinase and to activate pyruvate dehydrogenase phosphatase was investigated. Compound 1a did not show any significant activity, which may be taken as a strong indication that the GPI anchors are not the precursors of the IPG mediators.

Animals↗
PubMed2000

Genetic analysis of HIV-1 samples from Spain.

To characterize the viruses responsible for the HIV-1 epidemic in Spain, we genetically characterized 79 samples obtained from Spanish patients with different risk practices (injecting drug users and male homosexuals) in two regions (Madrid and Navarra). Genetic characterization was carried out by nucleotide sequencing in the C2-V3-C3 region and by phylogenetic analysis. All samples were of subtype B except one that clustered with clade F. Because no segregation of samples was determined according to the risk group of patients nor to their geographic origin, the Spanish samples analyzed constitute a single group of viruses. These data, along with the starlike topology of the phylogenetic tree, support the existence of a single introduction of HIV-1 subtype B in Spain. The mean genetic distance among subtype B sequences was of 13.9%+/-0.06% (range, 5%-25%), suggesting an epidemic of long evolution. Analysis of sequences in relation to isolation dates revealed an increase in the heterogeneity of the nucleotide sequences with time. According to these data, a divergence rate of 0.49%+/-0.11% per year was calculated for the Spanish samples during the period analyzed.

Amino Acid Sequence↗
PubMed2000

Involvement of Fcgamma receptor IIIA genotypes in susceptibility to rheumatoid arthritis.

OBJECTIVE: To investigate a possible association of Fcgamma receptor IIIA (FcgammaRIIIA) gene polymorphism at position 158 with susceptibility to, and the outcome of, rheumatoid arthritis (RA). METHODS: One hundred seventeen RA patients and 142 unrelated healthy control subjects from the same geographic area were studied. Genotyping for FcgammaRIIIA-158V/F was performed by a method based on polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis using amplification-created restriction sites. HLA-DRB1 typing by PCR-sequence-specific oligonucleotide hybridization (reverse hybridization) was also performed. RESULTS: Allele and genotype distributions in healthy controls were similar to those reported in other populations. The overall distribution of genotypes in the patients was significantly different from that in the controls (P = 0.023, by chi-square test from 3 x 2 contingency table). An overrepresentation of the FcgammaRIIIA-158FF genotype in the patients was observed (for 158FF versus non-158FF P = 0.01, odds ratio [OR] 1.98, 95% confidence interval [95% CI] 1.16-3.4). However, the FcgammaRIIIA-158VF genotype was increased in controls (for 158VF versus non-158VF P = 0.021, OR 0.54, 95% CI 0.32-0.92). No associations were found with any of a series of clinical parameters. Analysis of FcgammaRIIIA-158FF along with shared epitope showed that the presence of both factors increased the susceptibility to RA (P = 0.0009, OR 3.6, 95% CI 1.63-8.01); however, they probably do not interact to produce this effect. CONCLUSION: These results indicate that the FcgammaRIIIA-158 genotypes confer differential susceptibility to RA in our study population. Further studies to elucidate the role of this polymorphism in the pathogenesis of RA and other autoimmune diseases are warranted.

Adult↗
PubMed2000

Carpal tunnel syndrome: usefulness of sonography.

The aim of this study was to evaluate sonographic signs described for carpal tunnel syndrome (CTS). Sixty-four wrists from 40 patients with CTS confirmed by electromyography, and 42 wrists from 24 healthy individuals, were examined using sonography. Cross-sectional area, flattening ratio in proximal, middle and distal segments of the carpal median nerve and bowing of the flexor retinaculum were measured. The accuracies of the sonographic diagnostic criteria for CTS were assessed using receiver-operating-characteristic (ROC) analytical techniques. A significant swelling of the median nerve was observed at the proximal (p < 0.001), middle (p < 0.0001) and distal (p< 0.0001) segments and a significant bowing of the flexor retinaculum in CTS patients with respect to healthy subjects. No significant differences were found in the mean value of flattening ratio between the groups. The sensitivity, specificity, positive predictive value, and the negative predictive value were 73.4, 57.1, 72.3 and 58.5%, respectively, in the proximal and middle segments; 75, 57.1, 72.7 and 60% in the distal segment for areas greater than 11 mm2: and 81.3, 64.3, 77.6 and 69.2% for the bowing of the flexor retinaculum greater than 2.5 mm. All sonographic criteria were found in 34 CTS patients (53.1%) and none in 3 patients. Sonography may be useful in the diagnosis of CTS. The most reliable sign was increased bowing of the flexor retinaculum and cross-sectional area of median nerve with specificity close to 60%.

Adult↗
PubMed2000

Compression of the ulnar nerve in Guyon's canal by uremic tumoral calcinosis.

We describe the case of a 70-year-old woman with chronic renal failure on haemodialysis presenting with an ulnar nerve compression in Guyon's canal secondary to uremic tumoral calcinosis. Excision of calcium deposits and external neurolysis of the ulnar nerve were successfully performed. Simultaneously, the hyperphosphatemia and hypercalcemia were corrected. The pathogenesis of this condition is different from primary tumoral calcinosis. Clinical and radiological features and therapy are discussed. Uremic tumoral calcinosis is an unusual etiology of ulnar nerve compression in Guyon's canal not previously reported in dialysis patients.

Aged↗
PubMed2000

The procurement team as a factor of bone allograft contamination.

We studied the effect of the procurement team on the risk of contamination in 270 large bone allografts retrieved from 53 non-living donors under strictly aseptic conditions.The overall contamination rate was 8.1%. When the procurement team was constituted by three or less members the contamination rate was 5.6%, while if there were four or more members the rate was 12.9%; this difference was significant in the statistical analysis.We conclude that a procurement team constituted by three or less trained members is a determinant factor in decreasing the bacterial contamination rate of bone allografts.

Journal Article↗
PubMed2000

In vitro susceptibility of Escherichia coli strains isolated from diarrhoeic dairy calves to 15 antimicrobial agents.

The in vitro activities of 15 antimicrobial agents against 195 strains of Escherichia coli isolated from dairy calves affected by neonatal diarrhoea were determined. Of these strains 137 produced one or more potential virulence factors (F5, F41, F17, cytotoxic necrotizing factor, verotoxin and the eae gene), but the remaining 58 strains did not produce any of these factors. The overall percentage of resistant strains to streptomycin, tylosin and tetracycline was very high (above 65%). A high level of resistance (from 23 to 50%) to ampicillin, neomycin, kanamycin, spectinomycin, chloramphenicol, sulphadimethoxine and trimethoprim was also detected. The E. coli strains were very susceptible (89-95%) to apramycin and gentamicin and highly susceptible (99-100%) to polymyxin B, florfenicol and nitrofurazone. Some significant differences (P < 0.05) in the frequencies of resistance to some of the antimicrobials tested and in the rates of multi-drug resistance among the strains producing potential virulence factors and non-fimbriated, non-toxigenic, eae-negative strains were found. Most of the strains showed multi-resistance: 76.9% of the isolates were resistant to at least two antibiotics, 67.7% were resistant to at least four antibiotics and 50.3% were resistant to at least six antibiotics.

Animals↗
PubMed2000

Correlation of central venous pressure with Doppler waveform of the common femoral veins.

The objects of this prospective study were to determine the nature of the flow in the right femoral vein and to correlate the flow velocity with the venous pressure measured in the right atrium. We performed 236 pulsed Doppler ultrasonographic examinations in 1 year on patients with a venous catheter with the distal tip in the right atrium. In the Doppler wave readouts we analyzed wave frequency, velocity components, and relationships among them and the existence of pulsatile flow. These parameters were then compared to the right atrium pressure. We investigated the correlation between the atrium pressure and the flow velocity obtained from the Doppler waveforms of the common femoral veins, obtaining a significant correlation (P<0.0001) with the following: the atrium systolic wave a, the atrium diastolic wave v, the pulsatility ratio (PR = Vmin/Vmax) and the pulsatility index (PI = [Vmax - Vmin] /Vavg). The receiver operating characteristic showed that the pulsed Doppler ultrasonography is not a sensitive technique in diagnosis high atrium pressures. In addition, both cardiac and respiratory phasicity of the venous wave was observed. A significant inverse relation was found between the pulsatile flow and high atrium pressure. Nonetheless, the low sensitivity of this technique does not allow the use of pulsatile Doppler ultrasonography in the common femoral vein for diagnosing increases of the atrium pressure.

Adolescent↗
PubMed2000

Is 1-week treatment for peptic ulcer healing sufficient and safe?

OBJECTIVE: To confirm whether 1-week anti-Helicobacter therapy to achieve ulcer healing is sufficient and safe. METHODS: We retrospectively analyzed patients with peptic ulcer who were infected with Helicobacter pylori and treated with 3 different 7-day regimens, according to predefined protocols in 3 different centers in the same geographical area (Aragón, Spain). Three combinations commonly described in the literature were used: a) omeprazole (40 mg/24 h), tetracycline hydrochloride (2 g/24 h), colloidal bismuth subcitrate (480 mg/24 h) and metronidazole (750 mg/24 h) (OBTM, n = 105); b) omeprazole (40 mg/24 h), clarithromycin (1.5 g/24 h) and amoxicillin (3 g/24 h) (O40C1.5A3, n = 13); and c) omeprazole (40 mg/24 h), clarithromycin (1 g/24 h) and amoxicillin (2 g/24 h) (O40C1A2, n = 4). In all patients the diagnosis of peptic ulcer disease was confirmed endoscopically, and H. pylori infection was verified with urease testing and histological analysis. After treatment ended, no other antacids were allowed until after endoscopic examination to check eradication and ulcer healing. RESULTS: 122 patients were included (107 with duodenal ulcer, 12 with gastric ulcer and 3 with both). Compliance was good and side effects infrequent and mild. Eradication rates were 88.5% (93/105) in the OBTM group, 100% (13/13) with O40C1.5A3, and 75% (3/4) with O40C1A2. Healing was achieved in 98.16% (107/109) of the patients in whom the bacterial infection was eradicated, and in 23.07% (3/13) of those in whom it was not (p < 0.0001). No patient had any complications during the period without treatment. CONCLUSIONS: 1-week eradication therapy with previously described combinations commonly used in clinical practice achieves high ulcer healing rates with no complications in the period without antacid treatment. We consider that it is not necessary, at least in most patients, to prolong antacid therapy.

Anti-Bacterial Agents↗
PubMed2000

Changes in protein synthesis and acid tolerance in Clostridium perfringens type A in response to acid shock.

The induction of acid-shock proteins and the degree of acid resistance conferred on Clostridium perfringens by acid shock, and the kinetics of this resistance were determined. A sublethal acid shock at pH 4.5 for 20 min increased the acid tolerance of cells at least fifteenfold. The acquired tolerance was maintained for 3 h after acid treatment. The response of the microorganism to acid shock was also examined by analysis of pulse-labeled proteins. Five acid-shock proteins (molecular weights 120, 84, 58, 45 and 17 kDa) were identified by polyacrylamide gel electrophoresis.

Bacterial Proteins↗
PubMed2000

[Tolerability and safety of levofloxacinin long-term treatment].

Levofloxacin is a useful quinolone for patients infected with osteomyelitis or tuberculosis. There is little information on the tolerance and safety of levofloxacin in long-term treatment. Fifteen patients (10 men and 5 women) with prosthetic joint infection or chronic osteomyelitis were analyzed. The treatment was levofloxacin (500 mg/d) and rifampicin (600 mg/d). Controls were performed monthly during the treatment, and after that every six months. Problems that were likely related to medication were noted by medical interview. Analyses of hepatic and renal function were performed at each visit. The mean age was 64 years. Ten patients had prosthetic joint infection, two chronic osteomyelitis, two osteosynthetic device infection and one silicone graft infection. Staphylococcus aureus was isolated in eight cases, staphylococcus coagulase being negative in five, and the cultures negative in two cases. The mean duration of treatment was 3.6 months (range 2-6 months). No adverse reactions were observed in seven patients (46%). Occasional digestive symptoms were reported in six patients (40%), and two cases (13%) presented light diarrhea. These patients also took antiinflammatory treatment. Sleeplessness was observed in one patient (6%). Tendinitis or alterations in hepatic function were not observed. In no case was the treatment changed due to adverse reactions. It was concluded that levofloxacin is well tolerated and safe and could be an option for infections that require long-term treatment.

Aged↗
PubMed2000

[Idiopathic chronic pancreatitis (with diffuse stenosis of Wirsung's duct) in ulcerative colitis].

We describe a case of chronic idiopathic pancreatitis associated with ulcerative colitis. Pancreatitis is a rare extra-intestinal manifestations of inflammatory bowel disease. Chronic idiopathic pancreatitis associated with ulcerative colitis are usually painless, without calcification, with stricture of the main pancreatic duct and with severe exocrine pancreatic insufficiency.

Chronic Disease↗
PubMed1999

Chromosome 11 abnormalities in myelodysplastic syndromes.

Cytogenetic studies were performed in 140 patients with myelodysplastic syndrome (MDS) at diagnosis. Chromosome 11 anomalies were found in 7 cases (5%); 2 of these patients had refractory anemia (RA), 2 had refractory anemia with excess of blasts (RAEB), 1 had RAEB in transformation (RAEB-t), and 2 had chronic myelomonocytic leukemia (CMMoL) according to the French-American-British (FAB) Cooperative Group criteria. The chromosome 11 abnormalities comprised trisomy 11 (2 patients), monosomy 11 (1 patient), del(11)(q23) (2 patients), add(11)(p15) (1 patient), and der(11) t(3;11)(p21;q23) (1 patient). Abnormalities involving band q23 of chromosome 11 occurred in 3 cases and were the most common alteration. However, specific chromosomal alterations were not associated with any FAB classification group. These findings and their implications in the biology of MDS are discussed.

Aged↗
PubMed1999

Heterosexual transmission of HIV-1 is associated with high plasma viral load levels and a positive viral isolation in the infected partner.

Risk factors for heterosexual HIV transmission are not fully understood. In fact, a proportion of people with sexual exposure to HIV remain uninfected despite multiple and continuous intercourse with HIV-infected partners. In this work, we have analyzed those virologic parameters potentially involved in the transmission of HIV through heterosexual contact. Thirty-eight couples with continuous unprotected sexual intercourse were included. HIV transmission occurred in 10 of 38 couples. No differences in clinical characteristics, exposure time, sexual practices, CD4 counts, or polymorphism in CCR5 were found between transmitter and nontransmitter groups. In contrast, virologic data were different between both groups; median values of viral load were 21.139 and 5.484 RNA copies/ml of plasma in the transmitter and nontransmitter groups, respectively, and a significant difference was found in mean viral load values (p = .03, Mann-Whitney test). Viral isolation was obtained in 90% of transmitters, but in only 44% of nontransmitter subjects (p = .02, Fisher's exact test). These data show that viral load levels and a positive viral isolation in culture must be considered as risk factors for heterosexual transmission of HIV-1.

Adult↗
PubMed1999

Cryptosporidium and concurrent infections with other major enterophatogens in 1 to 30-day-old diarrheic dairy calves in central Spain.

Faeces samples from 218, 1 to 30-day-old, diarrheic dairy calves in 65 dairy herds were screened for the presence of Cryptosporidium and concurrent infections with rotavirus, coronavirus, F5 Escherichia coli and Salmonella spp. Calves were grouped according to their age as follows: 1-7, 8-14, 15-21 and 22-30 days. Cryptosporidium infection was detected in 43.8%, 71.9%, 63.2% and 6.9% of the calves in the respective age groups. Significant differences in the detection rate of Cryptosporidium were found between the age group 22-30 days and all other age groups, and between the age group 1-7 days and the age groups 8-14 days and 15-21 days. Cryptosporidium was the only enteropathogen detected in 60 of the 114 (52.6%) diarrheic calves. Concurrent infections with other enteropathogen(s) were detected in 64.3%, 46.3%, 39.5% and 0% of the Cryptosporidium-infected calves in the age groups 1-7, 8-14, 15-21 and 22-30 days, respectively. A significant age-associated decrease in the detection rate of mixed infections (p < 0.05) was found. The detection rates of the other enteropathogens considered in calves with Cryptosporidium infection were 87% for rotavirus, 11.1% for coronavirus, 27.8% for F5+ E. coli and 1.8% for Salmonella.

Agglutination Tests↗
PubMed1999

Prevalence and characteristics of necrotoxigenic Escherichia coli (NTEC) strains isolated from diarrhoeic dairy calves.

Fecal samples from 246, 1-90-days old diarrhoeic dairy calves in 72 herds were screened for the presence of cytotoxic necrotizing factors (CNF)-producing Escherichia coli (NTEC). NTEC were detected by tissue culture assays and PCR in 39 (15.8%) of the diarrheic calves, and the majority of these animals (34 of 39, ca. 87.2%) were infected by NTEC producing CNF2. Calves were grouped according to their age (1-7 days, 8-14 days, 15-21 days, 22-30 days and 31-90 days) and analyses of prevalence were done by the Mantel-Haenzsel chi2-test for trend. A significant age-associated increase in the prevalence of NTEC producing CNF2 (p<0.0001) was found. Eighty-one (8.4%) of the 958 E. coli isolates from the 246 diarrheic calves were positive for CNF in the tissue culture assays. These strains were analyzed by PCR and this technique showed that three (3.7%) strains were CNF1-positive and 75 (92.6%) were CNF2-positive. Moreover, three of the strains positive in the tissue culture assays were negative by PCR. These strains were subsequently assayed in several biological tests (rabbit skin test, mouse intraperitoneal test and mouse footpad test) which showed that they were really NTEC, probably producing CNF2, but with some different properties to classical strains producing CNF2. NTEC strains producing CNF2 belonged to different serogroups (O2, O7, O9, O14, O15, O41, O43, O45, O55, O76, O86, O88, O109, O115, O123, O128, O153 and O159) than strains producing CNF1 (O11 and O32) or PCR-negative strains (O111). Moreover, a strong association between CNF2 and F17 fimbriae was found (78.6% of CNF2-positive strains were F17-positive, whereas only 22.9% of CNF2-negative strains were F17-positive).

Agglutination Tests↗
PubMed1999

Distribution of lithium in different CNS areas and other tissues of adult male and female vizcacha (Lagostomus maximus maximus).

In a previous study (1) we demonstrated that lithium administration (1.0 mmol/kg b.wt., per day for 4 weeks) in intact vizcacha (Lagostomus maximus maximus) leads to significant histological alterations in the kidneys, ovarie and testicles, while these three tissues were not damaged in rats. Male vizcachas died within 4 days when administered LiCl 3 mmol/kg b.wt., while females were not affected. The lithium renal clearance presented no changes in either males or females. The 1.0 mmol/kg b.wt. dose was used in the experiments (2). In this study we examined the distribution of lithium in various tissues of male and female vizcacha (Lagostomus maximus maximus) administered LiCl by injection (1 mmol/kg b.wt.) for one day (Group I) and thirty days (Group II). Blood sample was obtained after 24 hours (Group I) and 30 days (Group II). The tissues investigated were: pituitary, hypothalamus, cerebral cortex, cerebellum, corpus callous, small and large intestine, kidney and suprarenal. The concentration of lithium in tissues and serum was determined by atomic absortion spectrometry (3,4). In Group I a significant lithium concentration increment (mumol/g of tissue) was observed in all the tissues of male vizcachas as compared to female vizcacha. A similar distribution was obtained in animals treated for 30 days. In the pituitary, however this difference between males and females was not significant. The male lithium serum levels were significantly higher than those of female animals. In conclusion, we suggest that the particular structure of the cell membrane (e.g., number and characteristic of sodium channels) of each tissue and/or the intracellular mechanisms of transport, elimination and metabolism might explain the unequal lithium distribution and the difference recovery from the damage produced. The results suggest that the vizcacha could be a useful model for the study of lithium toxicity.

Adrenal Glands↗