Biomedical subjects

C García

Publications and source records attributed to C García.

At least 127 records · Page 7Linked to original sources

PubMed1998

Phagocytosis and killing of slime-producing Staphylococcus epidermidis bypolymorphonuclear leukocytes. Effects of sparfloxacin.

The interaction of slime-producing Staphylococcus epidermidis (S+ strain) with human polymorphonuclear leukocytes (PMNs) was analyzed. The phagocytosis index (PI) and the killing index (KI) were evaluated, and the effect of subinhibitory concentrations (sub-MICs) of sparfloxacin in this interaction was determined. The study was carried out in parallel with a non-slime-producing strain (S- strain). The MIC values of sparfloxacin against both strains was 0. 06 mg/ml. In the S- strain the mean values of PI and KI were 82% and 31%, respectively, whereas in the S+ strain these values diminished to 49% and 8%, respectively (p <0.05) when the inocula were prepared in aerobiosis. In a constant flow atmosphere of 5% CO2, the results were similar to the previous ones in the S- strain (PI = 79% and KI = 27%), whereas in the S+ strain a increase in the PI (59%) and a similar value to the KI (9%) were observed. Significant increases (p <0.05) in the PI were noted when PMNs were preincubated with 1/4 and 1/16 MIC of sparfloxacin, and S. epidermidis S+ grown in aerobiosis were used. In the other assays the variations in PI and KI were not statistically significant (p >0.05). Our results confirm that slime protects against phagocytosis and killing by PMNs, although they also suggest that the S+ strains possess additional properties which make them resistant to the action of the PMNs.

Aerobiosis↗

PubMed1998

[Identification, by Western blot, of Fasciola hepatica immunogens recognized by the sera of experimentally infected rats].

This paper was aimed at identifying the main components present in the excretory-secretory antigens of adult parasite which are recognized by the sera of rats experimentally infected with metacercariae of Fasciola hepatica, by using the Western Blot technique. The cynetics of antibodies was also determined with and indirect ELISA. The results obtained allowed to find 31 components with approximate molecular weights from 11 to 136 kD. The predominant fractions were the following: 11-13 kD, 14-16 kD, 23-33 kD, 55-57 kD, 65-71 kD, and 86-136 kD. Antibodies were detected from the 2nd. week of infection in 80% of the animals and from the 3rd. week in 100% of them. There were no antibodies during the first week. The identification of these antibodies may contribute to a better understanding of the mechanisms of immunity linked with the infection by F. hepatica.

Animals↗

PubMed1998

[Effect of maternal smoking on offspring growth].

BACKGROUND: Maternal smoking negatively affects birth weight, breast milk volume and growth at one month of age. AIM: To study the effect of maternal smoking on the growth of three month old infants. SUBJECTS AND METHODS: Ten smoking and 10 non smoking mothers with one month old children, under exclusive breast feeding, were selected for the study. Urinary cotinine levels in the mothers and children were measured to assess smoking. Two months later, children were reassessed. RESULTS: Smoking mothers consumed a mean of 6.5 cigarettes/day. Compared to non smokers, urinary cotinine levels were higher in these mothers (60 +/- 21 and 1428 +/- 716 ng/ml respectively, p < 0.001) and their offspring (21 +/- 20 and 156 +/- 101 ng/ml respectively p < 0.001). Compared with smokers, at three months of age, children of non smoking mothers had a higher average weight (5829 +/- 498 and 6325 +/- 427 g, p < 0.02). CONCLUSIONS: Measurement of urinary cotinine levels is a reliable and objective measure of maternal smoking and nicotine transfer to the offspring. It also allows the assessment of passive smoking. Maternal smoking adversely affects child growth at three months of age.

Adult↗

PubMed1997

Transplacental infection following exposure of gilts to porcine reproductive and respiratory syndrome virus at the onset of gestation.

Twenty-five gilts without measurable porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) serum antibody titres were used for this experiment. All of them were randomly assigned to one of the treatment groups at the time of artificial insemination. Twelve gilts were exposed to PRRSV, of these, six were slaughtered on day 10 after exposure and constituted group A. The remaining six were slaughtered on day 20 after infection and constituted group C. Thirteen gilts were used as controls, six of these were slaughtered on day 10 after treatment and constituted group B. The remaining seven were slaughtered on day 20 after treatment and constituted group D. The infected gilts were inoculated with PRRSV intranasally and intravenously in the ear vein. They were observed for clinical signs of infection and the effects on conception and fertilization rates were studied, while the gilts and their embryos were tested for PRRSV and homologous antibodies. The infected animals developed signs of PRRS associated with anorexia and slight pyrexia. Infection was verified by reisolation of the virus from serum and other tissue samples and also by seroconversion. Ten out of 12 infected gilts and 10 out of 13 controls were pregnant at the time of slaughter and the ratio of embryos to corpora lutea was the same in both, infected and control groups (0.75). Therefore, infection with PRRSV at the onset of gestation did not appear to interfere with conception and fertilization rates and subsequent pregnancy. The PRRSV was not isolated from any of the embryos collected at day 10 postexposure, but was present in 20-day-old embryos of group C gilts. In this group, 60% of litters were infected prenatally, with 16% of embryos infected. The proportion of dead embryos was three times greater than in a control group D (35.4% and 9.8%, respectively). The results of this report indicate that exposure of susceptible gilts to PRRSV at the onset of gestation has no significant effect on conception and fertilization rates. However, although infection does not appear to have any effect on the embryos before implantation, it can result in transplacental infection and embryo death.

Animals↗

PubMed1997

Chemical basis of the resistance of barley seeds to pathogenic fungi.

The 5-(n)-alkylresorcinol fraction of the epicuticular waxes of Hordeum vulgare seeds appeared to be responsible for their in-born resistance to pathogenic fungi such as Aspergillus niger and Penicillium crysogenum. The antifungal properties of this fraction were evaluated qualitatively and quantitatively with a novel bioassay where the extreme lipophilicity of these compounds was taken into account. The minimum inhibitory concentration in the fungi tested ranged from 5.6 to 10 micrograms cm-2 for the alkyresorcinols. The behaviour of the different cultivars against these fungi could be predicted by measuring the natural amount of resorcinols of each variety by TLC-scanning densitometry. The ranking of cultivars thus established correlated well with the field behaviour of each cultivar, providing a useful and rapid method for predicting the behaviour against fungi of new varieties being developed.

Chromatography, Thin Layer↗

PubMed1997

Insemination of susceptible and preimmunized gilts with boar semen containing porcine reproductive and respiratory syndrome virus.

Twenty-one gilts without measurable PRRSV serum antibody titres were identified for this experiment. Seven gilts were used as controls (Group C) and 14 as principals. Of these, 7 gilts were preimmunized to PRRSV and constituted Group B, while 7 gilts remained seronegative and constituted Group A. The principal gilts were inseminated with boar semen containing PRRSV and were killed 20 d later. The control gilts were treated similarly but were not exposed to PRRSV. Gilts were observed for clinical signs of infection. The effects on the conception rates were studied and gilts and embryos were tested for PRRSV and homologous antibodies. Group A and B gilts developed signs of PRRS associated with anorexia and slightly elevated body temperatures. Transmission of the infection was demonstrated by the isolation of PRRSV from serum and other tissue samples of principal gilts and also by seroconversion. The results show that early infection may have an insignificant effect or no effect on the conception and fertilization rates. However, exposure to PRRSV at the time of insemination can result in transplacental infection of embryos. In Group A gilts, 5 of 6 litters were infected prenatally with 7.6% of embryos infected. In Group B gilts, 1 of 5 litters and 1.3% of embryos were infected. Moreover, approximately 2 and 4 times more embryos were dead in litters of gilts from Group A and Group B than in gilts from control Group C. The isolation of PRRSV in 3 dead embryos suggests that the embryos may have died as a result of the direct effect of the virus. It can be concluded that the insemination of either seronegative or preimmunized gilts with boar semen containing PRRS V may have an insignificant effect or no effect on conception and fertilization rates, although it can result in transmission of the virus and embryonic infection and death.

Journal Article↗

PubMed1997

Isolation, characterization and comparison of a novel crustacean toxin with a mammalian toxin from the venom of the scorpion Centruroides noxius Hoffmann.

A novel crustacean-specific toxin, Cn5, containing 66 amino acid residues was isolated from the venom of the scorpion Centruroides noxius Hoffmann. It is stabilized by four disulfide bridges, formed between Cys12-Cys65, Cys16-Cys41, Cys25-Cys46 and Cys29-Cys48. Toxicity tests revealed that Cn5 is a toxin that affects arthropods but not mammals. However, at high concentrations, Cn5 does displace the mammal-specific toxin Cn2 from rat brain synaptosomes. The concentration of Cn5 that produces half-maximal inhibition (IC50) was estimated to be 100 microM. Sequence comparison of Cn5 with toxin Cn2, a mammal-specific toxin from the same scorpion, showed the presence of two sequence stretches, at positions 30 to 38 and 49 to 58, where the majority of the differences are concentrated. On the three-dimensional structure of Cn5 it is demonstrated that these two sequence stretches form a continuous surface region near the site thought to bind to the sodium channel. We assume that this region might be implicated in determining species specificity.

Amino Acid Sequence↗

PubMed1997

Liver intracellular L-cysteine concentration is maintained after inhibition of the trans-sulfuration pathway by propargylglycine in rats.

To study the fate of L-cysteine and amino acid homeostasis in liver after the inhibition of the trans-sulfuration pathway, rats were treated with propargylglycine (PPG). At 4 h after the administration of PPG, liver cystathionase (EC 4.4.1.1) activity was undetectable, L-cystathionine levels were significantly higher, L-cysteine was unchanged and GSH concentration was significantly lower than values found in livers from control rats injected intraperitoneally with 0.15 M-NaCl. The hepatic levels of amino acids that are intermediates of the urea cycle, L-ornithine, L-citrulline and L-arginine and blood urea were significantly greater. Ura excretion was also higher in PPG-treated rats when compared with control rats. These data suggest a stimulation of ureagenesis in PPG-treated rats. The inhibition of gamma-cystathionase was reflected in the blood levels of amino acids, because the L-methionine: L-cyst(e)ine ratio was significantly higher in PPG-treated rats than in control rats; blood concentration of cystathionine was also greater. Histological examination of liver and kidney showed no changes in PPG-treated rats when compared with controls. The administration of N-acetylcysteine (NAC) to PPG-treated rats reversed the changes in blood urea and in liver GSH. These data suggest that when liver L-cysteine production was impaired by the blockage of the trans-sulfuration pathway, the concentration of this amino acid was maintained mainly by an increase in protein degradation and by a depletion in GSH concentration that may spare L-cysteine.

Acetylcysteine↗

PubMed1997

Effect of nitrous oxide and propofol on amino acid metabolism in neoplasic patients.

In a randomized controlled clinical trial, 14 patients requiring resection of tumors were divided in two groups: one group was anesthetized with nitrous oxide [67% N2O-33% O2 (vol/vol)] and the other with propofol. Two other groups of subjects were studied: a group of patients that was undergoing orthopedic procedures and was anesthetized with nitrous oxide [67% N2O-33% O2 (vol/vol)] and a control group (fasted for 10 hrs and no anesthesia). In patients requiring resection of tumors, the blood L-methionine concentration was significantly lower and the blood amino acid pattern was significantly affected after the administration of nitrous oxide (120-310 mins) compared with values after the induction of anesthesia and before surgery. The administration of propofol (120-240 mins) did not produce any of these changes. No patients required blood transfusion during surgery, and the patients had not previously been treated with cancer chemotherapeutic agents. The administration of nitrous oxide (60-150 mins) to patients undergoing orthopedic procedures did not affect blood L-methionine. It is concluded that the administration of nitrous oxide to cancer-bearing patients, but not to those undergoing orthopedic surgery, produced major changes in amino acid metabolism; therefore, consideration should be given to the avoidance of exposure of cancer patients to nitrous oxide.

Amino Acids↗

PubMed1997

Photophysical properties of gilvocarcins V and M and their binding constant to calf thymus DNA.

Absorption and emission techniques were used to characterize the ground (S0), singlet (S1) and triplet states (T1) of gilvocarcin V (GV) and gilvocarcin M (GM) in different solvents. Aggregation of GV with dimerization constant equal to 7800 M-1 is observed in 10% dimethyl-sulfoxide (DMSO)/water. The photophysical properties of the S1 state of these molecules are more sensitive to changes in solvent characteristics than the corresponding ground states. The absorption of visible light by GV and GM results in a higher dipole moment of the excited state causing a red shift in the fluorescence spectra with increasing solvent polarity. The fluorescence quantum yield remains practically unchanged with changes in solvent properties unless water is present as a co-solvent. Both phi f and tau f values corresponding to GV in DMSO are larger than those of GM, whereas in 10% DMSO/H2O the opposite is observed. Thus, GV is more susceptible to other deactivation pathways besides emission in the presence of water than GM. The relative phosphorescence quantum yield (phi p = 0.03) and the triplet energy (ET = 52 kcal/mol) of GV and GM are similar. The S0-S1 energy difference is 63 kcal/mol for GV, whereas for GM it is 67. Thus, the singlet-triplet energy difference is 11 and 15 kcal/mol, respectively. The PM3/CI calculated electronic structures of these compounds are consistent with the observed photophysical properties. The dark binding constants of GV to calf thymus DNA ([1.1-0.08] x 10(6) M-1) are about an order of magnitude larger than those of GM ([0.24-0.018] x 10(6) M-1) at different ionic strengths (0-2.00 M NaCl). Also, the number of gilvocarcin molecules bound per base pair is smaller for GM than for GV. These differences in dark DNA binding parameters between GV and GM could have implications in the large photocytotoxic ability of GV as compared to GM.

Aminoglycosides↗

PubMed1997

Ethnic differences in the clinical expression of systemic lupus erythematosus: a comparative study between African-Americans and Latin Americans.

Since ethnic differences in the disease expression of systemic lupus erythematosus (SLE) have been recognized, we compared the clinical and serological features in two different ethnic groups of patients with SLE. The study population consisted of 222 African-American and 300 Latin American (Colombian) SLE patients. Clinical, demographic, and laboratory data were obtained by chart review using a standard data collection form. African-American patients more commonly manifested discoid skin lesions, pulmonary fibrosis, and pleuritis, and less commonly manifested photosensitivity, livedo reticularis, and vascular thrombosis than did Latin Americans. In addition, there was a higher frequency of anti-Sm, anti-RNP, and anti-Ro positivity among African-American patients compared with Latin Americans. These results are additional evidence for the presence of ethnic differences in the clinical expression of SLE.

Adolescent↗

PubMed1997

Effects of luteinizing hormone-releasing hormone analog-induced pubertal delay in growth hormone (GH)-deficient children treated with GH: preliminary results.

To study the effect of delaying epiphyseal fusion on the growth of GH-deficient children, we studied 14 pubertal, treatment naive, GH-deficient patients (6 girls and 8 boys) in a prospective, randomized, placebo-controlled trial. Chronological age was 14.5 +/- 0.5 yr, and bone age was 11.6 +/- 0.3 yr (mean +/- SEM) at the beginning of the study. Patients were assigned randomly to receive GH and LH-releasing hormone (LHRH) analog (n = 8) or GH and placebo (n = 6) during 3 yr, with planned continuation of GH treatment until epiphyseal fusion. Patients were measured with a stadiometer and had serum LHRH tests, serum testosterone (boys), serum estradiol (girls), and bone age performed every 6 months. Patients treated with GH and LHRH analog showed a clear suppression of their pituitary-gonadal axis and a marked delay in bone age progression. We observed a greater gain in height prediction in these patients than in the patients treated with GH and placebo after 3 yr of treatment (mean +/- SEM, 14.0 +/- 1.6 vs. 8.0 +/- 2.4 cm; P < 0.05). These preliminary findings suggest that delaying epiphyseal fusion with LHRH analog in pubertal GH-deficient children treated with GH increases height prediction and may increase final height compared to treatment with GH alone.

Adolescent↗

PubMed1997

[Pulmonary nocardiosis: presentation of 3 clinical cases].

INTRODUCTION: Nocardiosis is an infectious disease that frequently involves to the respiratory tract. Nocardia asteroides is the predominant human pathogen. Nocardiosis is difficult to diagnose and that's why its incidence is not well established. CASES: Three cases diagnosed in a Pneumology Section are reported. None of them was affected by AIDS and all of them were initially diagnosed from bronchopneumonia. Empirical antibiotherapy was initiated and because of the unsatisfactory progress, bronchoscopy was performed in all cases and in one case a transthoracic puncture was made. Nocardia spp. was then isolated and this let to began with a specific treatment. All the patients progress satisfactorily in their respiratory infection. DISCUSSION: Although there are usually factors that predispose to nocardiosis, it can also occur in absence of these, as it happened in one of report patients. The clinical and radiological manifestations are not, in many cases enough to reach the diagnosis. Thus germ isolation is very important, and invasive procedures are often essential to obtain a quality samples to cultivate. Sulfonamides were considered drugs of choice, but nowadays, many authors propose trimethoprim-sulfamethoxazole. Imipenem, amikacin have also proved to be effective.

Adult↗

PubMed1997

[Gas embolism secondary to intraoperative use of hydrogen peroxide].

Hydrogen peroxide solution (H2O2) is used to irrigate and clean wounds. When applied to tissue hydrogen peroxide decomposes rapidly as a result of the action of catalases, releasing oxygen in the process. High pressure irrigation of the washing of closed cavities can cause serious complications. We report a case of gas embolism arising from the use of hydrogen peroxide during surgery for hydatidosis of the liver. A 64-year-old woman underwent surgery for removal of a hydatid cyst of the liver. When pressurized injection of 10 ml of 3% hydrogen peroxide was applied to the cystic cavity, cardiac arrhythmias were observed, a long with decreased PetCO2, hypotension and a "water mill" heart murmur. Gas embolism was suspected and treatment was instated immediately. Clinical course was good and without complications. We wish to warn against the potential dangers of using peroxide during surgery and of the importance of capnography for early diagnosis of gas embolism.

Embolism, Air↗

PubMed1997

Local production of oxygen free radicals and nitric oxide in rat diaphragm during sepsis: effects of pentoxifylline and somatostatin.

OBJECTIVE: To investigate the effect of giving lipopolysaccharide (LPS) on lipid peroxidation, and myeloperoxidase (MPO), nitric oxide (NO) synthase, and phospholipase A2 (PLA2) activities in rat diaphragm, and see whether they could be modified by giving pentoxifylline (PTXF) or somatostatin. DESIGN: Randomised experimental study. SETTING: Teaching hospital, Spain. MATERIAL: 76 Wistar rats divided into 4 groups of 19: control (saline/saline), LPS/saline, LPS/PTXF and LPS/somatostatin. INTERVENTIONS: The LPS was given intraperitoneally either 30 minutes (early, n = 10 in each group) or 120 minutes (late, n = 9 in each group) before treatment with saline, PTXF (45 mg/kg) or somatostatin (200 microg/kg) given intraperitoneally. Rats were killed 120 minutes after treatment. MAIN OUTCOME MEASURES: Malondialdehyde (MDA) and conjugated dienes content, and MPO, NO synthase, and PLA2 activities in diaphragmatic tissue. RESULTS: Conjugated dienes and MDA content, as well as MPO, NO synthase, and PLA2 activities were significantly increased in the rats given LPS. Independently of the timing of treatment, both PTXF and somatostatin completely prevented these increases. CONCLUSION: It is possible that treatment with PTXF or somatostatin may reduce the risk of ventilatory failure and speed recovery in septic patients.

Analysis of Variance↗

PubMed1997

[Hydrostatic reduction of intestinal intussusception in children. Experience in 43 cases].

BACKGROUND: Intestinal intussusception, a medical emergency, is more commonly idiopathic and ileocolic and occurs with higher frequency in children aged 6 months to 2 years. Barium enema confirms the diagnosis and allows its hydrostatic reduction, that is the treatment of choice of this condition. AIM: To report our experience with hydrostatic reduction of intestinal intussusception in children. PATIENTS AND METHODS: Hydrostatic reduction was attempted in 43 children with intestinal intussusception: 20 male, aged 2 to 48 months, that consulted at the Clinical Hospital of the Catholic University in Santiago. RESULTS: Hydrostatic reduction was successful in 33 children (77%) that were discharged from the hospital 24 to 96 hours after the procedure. A partial reduction was achieved in 10 patients (23%) who required surgery and were discharged from the hospital 5 to 8 days after the procedure. CONCLUSIONS: Our results are similar to those reported abroad and allow the recommendation of hydrostatic reduction as the treatment of choice for intestinal intussusception.

Barium Sulfate↗

PubMed1997

[Genotype and phenotype of apolipoprotein E in patients with Alzheimer's disease in Castille and Leon].

We determined the variants of the apolipoprotein E (apo-E) in a sample taken from a castellano-leonesa population with Alzheimer's disease (AD). The prevalence of the allele E-4 is 0.33 in AD and 0.12 in the control group. This results allow us to estimate that the risk of suffering from the disease is higher when the patients have an allele E-4. A significant correlation was found between the presence of the allele E4 and the AD (p < 0.005).

Aged↗

PubMed1996

Orthotopic xenografts of human pancreatic carcinomas acquire genetic aberrations during dissemination in nude mice.

Orthotopic transplantation of human tumors in nude mice reproduces the pattern of local growth and distal dissemination. The aim of our study was to determine the pattern of genetic alterations in human carcinomas of the exocrine pancreas orthotopically implanted and perpetuated in nude mice. Eight of the sixteen orthoimplanted human pancreatic carcinomas were perpetuated through several passages. Four perpetuated tumors followed distinct patterns of distal dissemination. Point mutations in the K-ras gene, genetic aberrations in the p53 and p16 genes, and allelic losses at retinoblastoma, adenomatous polyposis coli, and deleted in colorectal cancer loci were analyzed. Perpetuated tumors maintained the pattern of genetic alterations present in primary tumors. Five perpetuated tumors contained K-ras mutations, and all tumors contained p53 and/or p16 genetic aberrations. Allelic losses were present in four of the perpetuated tumors. Additional genetic alterations were detected in 6 of 35 metastases analyzed. Five of 9 peritoneal metastases or malignant ascitic cells acquired either K-ras or second p53 mutations. In contrast, only 1 of 25 liver metastases and none of the lymph node metastases acquired additional mutations. No additional p16 gene aberrations or other allelic losses were evidenced during tumor dissemination. We conclude that orthotopically implanted pancreatic carcinomas xenografted in nude mice show a high degree of genetic stability. Mutations in K-ras and p53 genes can occur in this model system in the more advanced stages of pancreatic tumor progression, mainly during peritoneal dissemination.

Adenocarcinoma↗