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Biomedical subjects

A Guzmán

Publications and source records attributed to A Guzmán.

At least 19 recordsLinked to original sources
PubMed2006

Bloodstream cells phenotypically identical to human mesenchymal bone marrow stem cells circulate in large amounts under the influence of acute large skin damage: new evidence for their use in regenerative medicine.

OBJECTIVES: Recent work has shown that human bone marrow contains mesenchymal stem cells (MSCs). However, little is known about their presence in peripheral blood. Since these cells are potentially responsible for tissue repair after injury, their number should be increased during these situations. To demonstrate their number during these situations, we measured MSCs in the peripheral blood of healthy donors and burn patients. MATERIALS AND METHODS: Blood samples were obtained from 15 acute burn patients and 15 healthy donors. We performed flow cytometric analysis, using a large monoclonal antibody panel: CD44, CD45, CD14, DR, CD34, CD19, CD13, CD29, CD105, CD1a, CD90, CD38, CD25. MSC phenotype was considered positive for CD44, CD13, CD29, CD90, and CD105, and negative for the other monoclonals. The testing was performed on day 3 after injury. We correlated the results with the age, sex, and size and type of burns. RESULTS: Cells expressing the MSC phenotype were detected in the peripheral blood of both groups. Noteworthy, compared with samples from healthy donors (0.0078 +/- 0.0044), blood obtained from burn patients showed a higher MSC percentage (0.1643 +/- 0.115; P < .001). The percentage of MSCs correlated with the size and severity of the burn. Increased values were also observed among younger patients. CONCLUSIONS: MSCs have an important role in regenerative processes of human tissues. We found cells phenotypically identical to MSCs circulating in physiological number in normal subjects, but in significantly higher amounts during acute large burns. Therefore, they may represent a previously unrecognized circulatory component to the process of skin regeneration.

Adult↗
PubMed2005

Acute health problems among subjects involved in the cleanup operation following the Prestige oil spill in Asturias and Cantabria (Spain).

The purpose of this study was to evaluate exposure conditions and acute health effects in subjects participating in the Prestige oil spill cleanup activities and the association between these and the nature of the work and use of protection devices in the regions of Asturias and Cantabria (Spain). The sample comprised 400 subjects in each region, selected from a random sampling of all persons involved in cleanup activities, stratified by type of worker and number of working days. Data were obtained via a structured questionnaire and included information on specific tasks, number of working days, use of protective materials, and acute health effects. These effects were classified into two broad groups: injuries and toxic effects. Data analysis was performed using complex survey methods. Significant differences between groups were evaluated using Pearson's chi(2) test. Unconditional logistic regression was used to compute odds ratios and 95% confidence intervals. Bird cleaners accounted for the highest prevalence of injuries (19% presented with lesions). Working more than 20 days in highly polluted areas was associated with increased risk of injury in all workers. Occurrence of toxic effects was higher among seamen, possibly due to higher exposure to fuel oil and its components. Toxic effects were more frequent among those working longer than 20 days in highly polluted areas, performing three or more different cleaning activities, having skin contact with fuel oil on head/neck or upper limbs, and eating while in contact with fuel or perceiving disturbing odors. No severe disorders were identified among individuals who performed these tasks. However, potential health impact should be considered when organizing cleanup activities in similar environmental disasters.

Accidents↗
PubMed2005

(1)H, (13)C NMR and X-ray crystallographic studies of highly polyhalogenated derivatives of costunolide lactone.

The costunolide lactone, a sesquiterpene compound isolated from Zaluzania triiloba species, reacted with several dihalocarbene sources produced by trihaloform-NaOH under successive phase transfer reactions yielding mono-, bis- and tris-dihalocyclopropane adducts. The structures, as well as the configurational assignments of the different derivatives, were established by (1)H and (13)C NMR spectroscopy and assisted by X-ray crystallographic and molecular modelling studies. The specific shielding of protons in the neighbourhood of different halogens on the cyclopropane moieties was correlated to the pseudocontact interactions.

Anthelmintics↗
PubMed2003

1H,13C 2D NMR and X-ray studies of the products of the reaction between dibenzylidencyclohexanone and 6-amino-1,3-dimethyl uracil.

The reaction of the 6-amino-1,3-dimethyl uracil with the dibenzylidencyclohexanone (1), provided three adducts whose structures result from nucleophilic attack yielding the monoadduct 3 and two isomeric bisadducts (4 and 5) in moderate yields (50-60%). The structures obtained in this study were elucidated with 2D high resolution NMR experiments, variable temperature NMR and X-ray crystallographic studies. In compound 3, the tricyclic skeleton is essentially planar and the cyclohexane ring addopts an envelope conformation. The structures 4 and 5 correspond to two isomeric spiro compounds.

Crystallography, X-Ray↗
PubMed2002

Early amniocentesis with the filtration technique: neonatal outcome in 123 singleton pregnancies.

OBJECTIVE: To evaluate results of a prospective study of pregnancies in which early amniocentesis with the filtration technique was performed at 10-13 weeks' gestation (mean 12.3 weeks' gestation). METHODS: 123 singleton pregnancies in which early amniocentesis with the modified filtration technique was performed at 10-13 weeks' gestation (mean 12.3 weeks' gestation). The amniotic fluid was aspirated into the syringe and reinjected through the filter. RESULTS: All the procedures were performed successfully by a single needle insertion. Neither dry taps nor filtration failures occurred. The mean time of amniocentesis was 4.02 min (95% confidence interval, 3 min and 36 s to 4 min and 18 s). The karyotyping success rate was 99.2%. Temporary amniotic fluid leakage occurred in three women (2.4%). There were 110 (89.4%) live births. Two cases of stillbirth occurred at week 38 and week 40. Two unintended losses occurred within three weeks after sampling (1.62%). Another additional unintended fetal death was notified at the 20-week screening ultrasonography. The total fetal-loss rate was 10.6%. In one case, talipes equinovarus was detected at the 20-week screening ultrasound study. CONCLUSIONS: Further studies are needed to determine the risk of amniotic leakage and its relation to duration of the procedure in patients undergoing early amnifiltration.

Amniocentesis↗
PubMed2002

2D 1H and 13C NMR evidences of the [2 + 2] autodimerization of 2-benzyl-5-benzylidene cyclopentanone yielding two different diphenyl, dispiro cyclobutane derivatives.

The ene-ene [2 + 2] cycloaddition of 2-benzyl-5-benzylidenecyclopentanone proceeds smoothly and spontaneously in benzene-d6 or deuteriochloroform solution to give two different diphenyl dispiro [4.1.4.1] dodecan-4,11-diones. Detailed 1H and 13C 2DNMR spectroscopy (COSY, HMQC, HMBC) were performed in order to prove the existence in solution of two cyclobutane derivatives, one a previously described photodimer obtained by the UV irradiation of crystals of 2-benzyl-5-benzylidenecyclopentanone.

Carbon Isotopes↗
PubMed2002

Behavior of adenine in Na-montmorillonite exposed to gamma radiation: implications to chemical evolution studies.

Adenine is an important compound in biological systems, such as genetic and energy utilization processes. Adenine is readily formed in prebiotic conditions. Its synthesis and stability in environmental conditions are of paramount importance in chemical evolution processes. Clay minerals might have played an important role in the early Earth. Clays are known to have a high affinity for organic compounds, and they may provide protection to adsorbed molecules against high-energy radiation. The purpose of this work is to testthese assumptions. We study the stability of adenine under irradiation, in aqueous solution and also adsorbed in a clay mineral. The recovery of adenine after a gamma irradiation was higher in the system containing clay in relation to a system without clay. Results show that adenine is readily adsorbed in the clay, and that the clay act as surface protector toward the degradation of adenine by the radiation.

Adenine↗
PubMed2001

Toluidine blue-O staining of prion protein deposits.

Prion diseases or transmissible spongiform encephalopathies are a group of fatal neurodegenerative diseases caused by an abnormal form of prion protein (PrP(sc)). In this study, we developed a sensitive histochemical detection of PrP(sc) deposits in a Gertsmann-Sträussler-Scheinker disease (GSS) patient using toluidine blue-O staining, a specific reagent to stain mucins and mucopolysaccharides. Detection of prion deposits correlated with immunohistochemistry using anti-prion antibodies. Control assays were performed using amyloid-beta (Abeta) plaques from Alzheimer's disease (AD) brains. Our results demonstrated that toluidine blue-O staining allowed to recognize 69.1+/-2.6% of the total plaques recognized by the anti-prion antibody. Furthermore, in the 15 studied brain regions from the GSS patient, toluidine blue-O revealed the same recognition pattern as anti-prion labeling. Toluidine blue-O stained specifically the prion deposits but not the Abeta plaques in AD brains. The specificity of the technique was confirmed in a Creutzfeldt-Jakob disease brain. This method opens several possibilities for postmortem diagnoses. Our results also suggest the relevance of specific post-translational modifications of PrP(sc), identified by toluidine blue-O, that might participate in the transformation of PrP(c) to PrP(sc).

Aged↗
PubMed2001

Four-week oral toxicity studies of the new quinolone antibacterial agent cetefloxacin tosylate in rats and marmoset monkeys.

Four-week oral toxicity studies with cetefloxacin tosylate ((-)-7[3-(R)-amino-2-(S)-methyl-1-azetidinyl]-1-(2,4- difluorophenyl)-1,4-dihydro-6-fluoro-4-oxo-3-quinolinecarboxylic acid tosylate, CAS 141725-88-4 (base), E-4868.Ts) a new quinolone antibacterial agent, were performed in Sprague-Dawley rats and marmoset monkeys at doses of 100, 450, 2000 mg/kg/d and 25, 50, 125, 300 mg/kg/d, respectively. In rats, due to its toxicity the high dose was decreased to 1000 mg/kg/d after 3 days of treatment. Mortality was recorded among high dose rats receiving 2000 or 1000 mg/kg/d. Rats receiving dosages of 450 or 2000/1000 mg/kg/d showed less activated mandibular lymph nodes, cortical lymphocyte depletion of mandibular and/or mesenteric lymph nodes, atrophy of the white pulp of the spleen, cortical atrophy of thymus and thymic apoptosis. Enlarged caeca, increased water consumption and variations in plasma electrolyte levels were observed in animals receiving these dosages and in male rats receiving 100 mg/kg/d. Low neutrophil counts were observed in rats receiving dosages of 100 or 450 mg/kg/d, and increased alkaline phosphatase and alanine transaminase plasma levels and slightly decreased plasma protein levels in females receiving 450 or 2000/1000 mg/kg/d. Marmosets receiving dosages of 50 mg/kg/d and above displayed several clinical signs which included emesis, diarrhoea, ptosis, occasional episodes of under- and overactivity, and excessive scratching activity. Skin reddening was observed during the first week of treatment in marmosets receiving 300 mg/kg/d. On the basis of the results obtained it can be concluded that the non-toxic doses of E-4868. Ts after 4-week oral administration in rats and marmoset monkeys were 100 and 25 mg/kg/d, respectively.

Animals↗
PubMed2000

Unusual lipid composition of a Bacillus sp. isolated from Lake Pomorie in Bulgaria.

The lipid composition of a Bacillus sp., isolated from Lake Pomorie in Bulgaria, was unusual and consisted of 26 different fatty acids between C12 and C26, with anteiso C15-C17 saturated fatty acids predominating. The furan fatty acid, 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid, was also identified, a new finding for this genus. The hydrocarbons consisted of 30 different monounsaturated hydrocarbons, between C25 and C30, with the iso-iso, iso-anteiso, anteiso-anteiso, iso-normal, and anteiso-normal methyl branching for odd-numbered chains, and the iso-iso, iso-anteiso, iso-normal, and anteiso-normal methyl branching for even-numbered chains. The double bond positions in these hydrocarbons were determined by dimethyl disulfide derivatization followed by GC-MS, and the double-bond cis configuration was confirmed by infrared spectroscopy. Some previously unknown hydrocarbons in bacteria, such as (Z)-3,21-dimethyl-9-tricosene, (Z)-3,21-dimethyl-10-tricosene, (Z)-2,24-dimethyl-11-pentacosene, and (Z)-2,25-dimethyl-13-hexacosene were identified. Sterols were detected and were based on the sitosterol nucleus.

Bacillus↗
PubMed2000

13C and 1H NMR of 2,6-diaryl-1-hydroxy piperidin-4-one oximes; substituent effects on cis/trans ratio and conformational equilibria.

The reaction of substituted diarylidene acetones with hydroxylamine hydrochloride affords isomeric N-hydroxy diaryl piperidinone oximes as main products. The structures as well as conformational equilibria of these products were established by 1H and 13C NMR spectroscopy and further studied by variable temperature NMR. It was found that the cis/trans ratio of 2,6-substituted piperidine derivatives depended on the position of the substituent on the aromatic ring.

Acetone↗
PubMed2000

Subchronic toxicity of the new quinolone antibacterial agent irloxacin in beagle dogs.

The subchronic oral toxicity of the new quinolone antibacterial agent irloxacin (6-fluorine-7-(pyrrol-1-yl)-1-ethyl-1,4-dihydro-4-oxo-quinolone- 3-carboxylic acid, CAS 91524-15-1) in Beagle dogs was investigated in studies of 4 and 29 weeks of duration. In both studies animals received dosages of 10, 120 and 1400 mg/kg/d. Pale coloured faeces were seen on animals receiving 1400 mg/kg/d. Animals receiving 1400 mg/kg/d for 29 weeks showed an increased incidence of wax in the ears during the latter half of the treatment period, and one male and one female experienced transitory locomotive difficulties at the end of the first week of treatment. The liver was identified as the target organ for toxicity with presence of lipofuscin in the hepatocytes of animals receiving 120 or 1400 mg/kg/d for 29 weeks. Slight increases in liver weights were observed in animals receiving 120 or 1400 mg/kg/d for 4 weeks, and in all groups receiving irloxacin for 29 weeks. However, no histopathological findings were observed in the liver of animals receiving irloxacin for 4 weeks or those receiving 10 mg/kg/d for 29 weeks. Other relevant findings observed in the 29 week study were increased triglyceride, phospholipid and cholesterol levels in males receiving 120 mg/kg/d and animals receiving 1400 mg/kg/d, increased albumin and decreased beta-globulin concentrations in females receiving 1400 mg/kg/d, and prolonged activated partial thromboplastin time in animals receiving 1400 mg/kg/d. On the basis of the results obtained it is concluded that 10 mg/kg/d can be considered as the non-toxic dose after 29 week oral administration of irloxacin in dogs.

Animals↗
PubMed1999

Facile syntheses for (5Z,9Z)-5,9-hexadecadienoic acid, (5Z,9Z)-5,9-nonadecadienoic acid, and (5Z,9Z)-5,9-eicosadienoic acid through a common synthetic route.

The delta 5,9 fatty acids (5Z,9Z)-5,9-hexadecadienoic acid, (5Z,9Z)-5,9-nonadecadienoic acid, and (5Z,9Z)-5,9-eicosadienoic acid were synthesized for the first time in four steps (9-12% overall yield) starting from commercially available 2-(2-bromoethyl)-1,3-dioxolane. The synthetic approach provided enough material to corroborate the structure and stereochemistry of (5Z,9Z)-5,9-nonadecadienoic acid which was recently identified in the flowers of Malvaviscus arboreus (Malvaceae). The novel phospholipids 1-hexadecanoyl-2-[(5Z,9Z)-5,9-eicosadienoyl]-sn-glycer o-3-phosphocholine and 1-octadecanoyl-2-[(5Z,9Z)-5,9-eicosadienoyl]-sn- glycero-3-phosphocholine were also synthesized from commercially available L-alpha-phosphatidylcholine (egg yolk) and characterized by positive ion electrospray mass spectrometry. These are the first examples of unsymmetrical phospholipids with saturated fatty acids at the sn-1 position and delta 5,9 fatty acids at the sn-2 position.

Animals↗
PubMed1999

Correlation of the changes of the frequency of perichromatin granules with the RNA content of the interchromatin region of uterine cells in normal and ovariectomized rats. A high resolution in situ hybridization and stereological study.

The changes in the number of perichromatin granules (PCG) and the alterations in the RNA content of the interchromatin and perichromatin regions caused by ovariectomy and estradiol injection were studied in rat endometrial fibroblast and myometrial muscle cells. Twelve rats were divided in four groups. A group of rats was fixed without any treatment, the other three groups were ovariectomized and processed 21 days after the operation. One of them was studied without further treatment, and two groups were injected intraperitoneally with 20 micrograms of 17 beta-estradiol hemisuccinate and fixed 0.5 and 2 h after the injection. The frequency of PCG was evaluated in preparations stained with EDTA procedure preferential for RNP. The alterations of RNA content were estimated by post-embedding high resolution in situ hybridization using a total DNA probe labeled with biotinilated nucleotides revealed by streptavidin coupled with 10 nm gold grains. Most of the non-nucleolar labeling is associated to RNP containing fibrils. Perichromatin and interchromatin granules are labeled to a lesser extent. Castration brings about a reduction of the number of PCG and of the numerical density of labeling in endometrial fibroblasts. The injection of estradiol causes a rapid increase in both parameters. On the contrary, the frequency of PCG and intensity of labeling of epithelial endometrial cells and in muscle cells increase after ovariectomy and are reduced by estradiol administration. These results suggest that estradiol may affect differentially various types of target cells in the same organ, and also that PCG are not the only nuclear compartment of pre-mRNA or mRNA altered by the changes in estradiol, the RNP containing fibrils located in the perichromatin and in the interchromatin regions are also involved.

Animals↗
PubMed1999

Acute and subchronic toxicity studies of the new quinolone antibacterial agent irloxacin in rodents.

Irloxacin (6-fluorine-7-(pyrrol-1-yl)-1-ethyl-1, 4-dihydro-4-oxo-quinolone-3-carboxylic acid, CAS 91524-15-1), a new quinolone antibacterial agent, was administered as a single dose to rats and mice both by oral and intraperitoneal route in oder to study its acute toxicity. Its oral subchronic toxicity was also assessed by treating rats for 4 and 13 weeks. The results obtained showed that irloxacin was well tolerated after single administration in mice and rats, with LD50 values above 2000 and 5000 mg/kg for intraperitoneal and oral administration, respectively. In the oral subchronic toxicity studies, the histopathological examination performed after the 13-week treatment period confirmed the kidney as the target organ for toxicity. Increased presence of lipofuscin in the kidneys was observed in animals receiving 2000 or 450 mg/kg/d, and degeneration and/or dilatation of proximal renal tubules and chronic interstitial nephritis in males receiving these dosages. No histopathological findings were observed in the kidneys of animals receiving 100 mg/kg/d for 13 weeks. Other relevant findings were, presence of dark or cloudy urine with slightly lower pH in animals receiving dosages of 450 mg/kg/d and above, increased urinary protein concentration in animals receiving 2000 or 450 mg/kg/d, and increased plasma urea concentration in those receiving 2000 mg/kg/d. Moreover, increased plasma phospholipids and total cholesterol concentration, and increased liver and kidney weights were observed among treated animals. As a summary, the results have shown that irloxacin has a low acute toxicity in both mice and rats. For repeat oral administration in rats, 100 mg/kg can be considered as the non-toxic effect level after a treatment period of 13 weeks.

Administration, Oral↗
PubMed1995

[Management of non-functioning renal graft].

On a series of 315 consecutive Renal Transplants (RT), the authors analyze the effects from any situation capable of causing the graft's renal failure, whether accompanied or not of oligoanuria. To begin with, the exploratory approach promoted by the ¿non-functioning kidney¿ is established recognizing three typical stages depending on the time of appearance: early, medium-term and long-term. The breakthroughs obtained in the prevention of Acute Tabular Necrosis (A.T.N.) are verified through the use of the receptor's hyperhydration, as well as the good results in the treatment of rejection since the arrival of Cyclosporin and the recent introduction of OKT3. Chronic rejection, is, today, the major cause of our transplantectomies (TX), since our attitude towards the exeresis of all irreversibly non-functioning grafts is well known. Vascular thrombotic problems have a very high percentage of losses among affected kidneys. Little can be done once the problem arises. Prevention is the best weapon available and special attention should be paid to the meticulousness of bank surgery and the suitable final positioning of the organ in the fossa iliaca, having into account the highly close relationship between this problem and the pathological and iatrogenic anomalies displayed by the organs to be transplanted in their arterial tree. The excretory tract problems are repaired in 83% cases, but the rest may even result in the loss of the kidney. In these complications, early surgery is the best way to avoid subsequent amputation surgery.

Graft Rejection↗