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Biomedical subjects

A Ibarra

Publications and source records attributed to A Ibarra.

At least 19 recordsLinked to original sources
PubMed2006

Influence of the intensity, level and phase of spinal cord injury on the proliferation of T cells and T-cell-dependent antibody reactions in rats.

STUDY DESIGN: Three independent experiments in a rat model of contusive spinal cord (SC) injury were performed. Two studied the alterations induced by SC injury on some immunological aspects of the T-cell response. The third one evaluated the motor recovery of rats with low-thoracic injuries. OBJECTIVE: To examine the effect of level, intensity and phase of SC injury on T-cell proliferation and T-cell-dependent antibody response. SETTING: Neuroimmunology Department, UIMEN, IMSS-CAMINA Research Center. METHODS: Lymphocyte proliferation and hemagglutination assays were performed. Animals were injured either moderately or severely at T1 or T12 SC segments. Analysis of peripheral T-cell proliferation in response to mitogens and to myelin basic protein (MBP), as well as of antibody production against a T-dependent antigen, was performed at acute, subacute and chronic phases. RESULTS: A significant decrease of both response to mitogens and antibody production was found especially during the acute phase and in animals with severe and high (T1)-level injury. Animals with low (T12) and moderate contusions recovered to control levels at the chronic phase. An autoimmune reaction against MBP was observed only in animals with severe contusion at low level. CONCLUSIONS: The intensity, level and phase of SC injury differentially alter the function of T cells. These results will allow a better interpretation of studies directed to elucidate the role of T lymphocytes in various processes developed after SC injury.

Animals↗
PubMed2006

Effect of obese living donors on the outcome and metabolic features in recipients of kidney transplantation.

Living kidney donors must be evaluated carefully focusing on risk factors for long-term complications. Our transplant center performs 70% of its kidney transplantations from living sources including 19.9% obese donors. We evaluated the long-term follow-up of recipients of organs from 37 living donor patients with obesity defined by a body mass index (BMI) > 30 kg/m2. We compared this group with a control group of normal BMI before donation. The follow-up was 50.8 +/- 28.5 months. We observed a lower glomerular filtration rate among organs from obese versus non-obese donors. At the same time we reviewed percentage of acute rejection episodes (ARE), primary allograft function, and surgical complications we observed incidence of ARE higher among the group who received kidneys from obese donors.

Adult↗
PubMed2006

Prevalence of erectile dysfunction in kidney transplant recipients.

Prevalence and severity of erectile dysfunction increase with advancing age. Patients with end-stage renal disease (ESRD) experience disturbances in erectile function related to organic factors including as uremia, hypertension, endocrine, and nonorganic factors like depression. Recipients of kidney transplants show a high prevalence of erectile dysfunction, 32.2% to 50.7%. We conducted a study of the prevalence of erectile dysfunction among male renal transplant recipients using the International Index of Erectile Function. Among 182 men with kidney transplantations, there were 89 recipients (48.9%) with erectile dysfunction; 60 recipients had normal sexual function (32.9%); and whereas 33 recipients had no sexual activity.

Adult↗
PubMed2005

Glutathione monoethyl ester improves functional recovery, enhances neuron survival, and stabilizes spinal cord blood flow after spinal cord injury in rats.

Secondary damage after spinal cord (SC) injury remains without a clinically effective drug treatment. To explore the neuroprotective effects of cell-permeable reduced glutathione monoethyl ester (GSHE), rats subjected to SC contusion using the New York University impactor were randomly assigned to receive intraperitoneally GSHE (total dose of 12 mg/kg), methylprednisolone sodium succinate (total dose of 120 mg/kg), or saline solution as vehicle. Motor function, assessed using the Basso-Beattie-Bresnahan scale for 8 weeks, was significantly better in GSHE (11.2+/-0.6, mean+/-S.E.M., n=8, at 8 weeks) than methylprednisolone (9.3+/-0.6) and vehicle (9.4+/-0.7) groups. The number of neurons in the red nuclei labeled with FluoroRuby placed caudally to the injury site was significantly higher in GSHE (158+/-9.3 mean+/-S.E.M., n=4) compared with methylprednisolone (53+/-14.7) and vehicle (46+/-16.4) groups. Differences in the amount of spared SC tissue at the epicenter and neighboring areas were not significant among experimental groups. In a second series of experiments, using similar treatment groups (n=6), regional changes in microvascular SC blood flow were evaluated for 100 min by laser-Doppler flowmetry after clip compression injury. SC blood flow fell in vehicle-treated rats 20% below baseline and increased significantly with methylprednisolone approximately 12% above baseline; changes were not greater than 5% in rats given GSHE. In conclusion, GSHE given to rats early after moderate SC contusion/compression improves functional outcome and red nuclei neuron survival significantly better than methylprednisolone and vehicle, and stabilizes SC blood flow. These results support further investigation of reduced glutathione supplementation after acute SC injury for future clinical application.

Animals↗
PubMed2005

[Evolution of methicillin resistance in Staphylococcus aureus in Cordoba (Spain) in the years 2002-2005].

In the last few years, methicillin-resistant Staphylococcus aureus (MRSA) has become a very important human pathogen. Our aim was to study the evolution of methicillin resistance of Staphylococcus aureus strains isolated in our hospital over a four-year period and to compare our situation with the rest of Spain and Europe. The rates varied from 39.9% in 2002 to 46.4% in 2005. Units with the highest rate were ICU and surgical wards. We found no glycopeptide-resistant strains.

Europe↗
PubMed2004

[Antimicrobial susceptibility of bacterial isolates from patients with cystic fibrosis].

We studied the antimicrobial susceptibility of bacteria isolated from sputum from patients with cystic fibrosis in our hospital during 2001 and 2002. The most frequently isolated microorganisms were Staphylococcus aureus (59.89%), Pseudomonas aeruginosa (49.45%), Stenotrophomonas maltophilia (4.9%) and Haemophilus influenzae (3.8%). The rate of methicillin-resistant S. aureus was 18%, and no strains with low susceptibility to glycopeptides were found. Carbapenems showed the highest activity against P. aeruginosa, although this did not reach 100%.

Adolescent↗
PubMed2003

Neuroendocrine-immune surveillance of osteosarcoma: emerging hypothesis.

Osteosarcoma is a bone-forming cancer predominantly found in children and adolescents more often than in adults. Osteosarcoma of the gnathic apparatus is relatively rare in the young population, and this condition becomes a concern of clinical dentists for predominantly the middle-aged and aging patient groups. Osteosarcomas are invaded by lymphocytes, which exhibit signs of activation. The immune processes that are engaged within the malignant bone matrix involve the production of cytokines, which regulate the process of apoptotic programmed cell death. This paper discusses the mechanisms by which apoptosis of osteosarcoma cells is modulated by the neuroendocrine-immune system, and potential physiological implications.

Adolescent↗
PubMed2003

[Susceptibility of Streptococcus pyogenes isolates from pharyngeal exudates in Cordoba (Spain)].

Streptococcus pyogenes is an important human pathogen. Betalactams are still the drug of choice for the treatment of infections caused by this microorganism. In recent years an increase in the use of macrolides for initial treatment in respiratory infections has been observed; consequently, the number of macrolide-resistant isolates has also increased. We investigated the susceptibility of S. pyogenes to penicillin, erythromycin, clarithromycin and clindamycin in Cordoba during 2000, 2001 and the first 6 months of 2002. We obtained 100 isolates of S. pyogenes from 1232 pharyngeal exudates, all of which were susceptible to penicillin and 39 of which were resistant to erythromycin and clarithromycin. Twenty-six of these 39 isolates were susceptible to clindamycin.

Clarithromycin↗
PubMed2003

[Methicillin resistant Staphylococcus aureus from clinical samples in Cordoba (Spain)].

Increases in methicillin-resistant Staphylococcus aureus (MRSA) strains and in isolates with reduced susceptibility to glucopeptides have become an important problem in the epidemiology of Gram-positive microorganisms. All the consecutive S. aureus collected in our hospital from 1995 to 2001 were studied. Of the 4531 isolates 24.23% were methicillin resistant in this period. The highest number of methicillin-resistant strains were found in wound exudates. In recent years an almost 20% increase in MRSA has occurred in our hospital. As MRSA strains are an important problem in our area and their prevalence is on the rise, as is multiresistance, the monitoring and control of MRSA strains in our hospitals is necessary.

Health Facilities↗
PubMed2001

Vaccination with a Nogo-A-derived peptide after incomplete spinal-cord injury promotes recovery via a T-cell-mediated neuroprotective response: comparison with other myelin antigens.

The myelin-associated protein Nogo-A has received more research attention than any other inhibitor of axonal regeneration in the injured central nervous system (CNS). Circumvention of its inhibitory effect, by using antibodies specific to Nogo-A, has been shown to promote axonal regrowth. Studies in our laboratory have demonstrated that active or passive immunization of CNS-injured rats or mice with myelin-associated peptides induces a T-cell-mediated protective autoimmune response, which promotes recovery by reducing posttraumatic degeneration. Here, we show that neuronal degeneration after incomplete spinal-cord contusion in rats was substantially reduced, and hence recovery was significantly promoted, by posttraumatic immunization with p472, a peptide derived from Nogo-A. The observed effect seemed to be mediated by T cells and could be reproduced by passive transfer of a T cell line directed against the Nogo-A peptide. Thus, it seems that after incomplete spinal-cord injury, immunization with a variety of myelin-associated peptides, including those derived from Nogo-A, can be used to evoke a T cell-mediated response that promotes recovery. The choice of peptide(s) for clinical treatment of spinal-cord injuries should be based on safety considerations; in particular, the likelihood that the chosen peptide will not cause an autoimmune disease or interfere with essential functions of this peptide or other proteins. From a therapeutic point of view, the fact that the active cellular agents are T cells rather than antibodies is an advantage, as T cell production commences within the time window required for a protective effect after spinal-cord injury, whereas antibody production takes longer.

Amino Acid Sequence↗
PubMed2001

[The impact of the implementation of staying in the United Kingdom for six months or more as donor exclusion criteria on the donor base of the Basque Country].

BACKGROUND: To reduce the risk of new variant Creutzfeldt-Jakob disease by blood products some countries exclude persons who have spent six months or more cumulatively in the United Kingdom as blood donors. METHOD: We asked our donors about this selection criteria to evaluate the loss of blood donors and donations in case of implementation of this measure. RESULTS: 11,681 donors and 1,648 refused persons were analyzed. 123 (1.05%) and 11 (0.66%) respectively fulfilled this criteria. CONCLUSIONS: In case of implementation of this selection criteria 1% of blood donors and 1.77% blood donations would be lost.

Adolescent↗
PubMed2000

Lipid peroxidation inhibition in spinal cord injury: cyclosporin-A vs methylprednisolone.

To compare the effectiveness of cyclosporin-A (CsA) with methylprednisolone (MP) or a combination of both upon inhibition of lipid peroxidation (LP) after spinal cord (SC) injury, rats were treated with either CsA, MP, CSA+MP or vehicle starting 1 h after SC contusion at T9 level. LP was assessed 24h after injury by the lipid fluorescent product formation method. The survival rate was also evaluated in other series of rats by the Kaplan-Meier curves. Lipid peroxidation was similarly inhibited in rats treated with CsA, MP, or CSA+MP (p>0.05). Animals receiving MP (alone or combined with CsA) showed the poorest surviving rate. LP was inhibited by CsA to the same extent as by MP but without the lethal effect of the latter.

Animals↗
PubMed2000

Search for an IgG response against neural antigens in experimental spinal cord injury.

In order to determine if a specific response is induced after spinal cord injury, we performed a kinetic search for IgG antibodies against various spinal cord antigenic preparations in a rat contusion model. Even though spinal cord injured animals showed two reactive bands, these could be originated by the reaction of natural antibodies, since they were also observed before lesion. Thus, these antibodies would not be of relevance in the pathogenic events of spinal cord injury in this rat model. Our findings do not demonstrate the existence of a specific IgG response against spinal cord constituents after injury.

Animals↗
PubMed1999

Cyclosporin-A inhibits lipid peroxidation after spinal cord injury in rats.

Besides its immunosuppressive/anti-inflammatory activity, cyclosporin-A (CsA) may protect damaged tissues from lipid peroxidation (LP) by free radicals. To determine the effect of CsA on LP spinal cord (SC) injury, Wistar rats were treated with either vehicle or CsA (2.5 mg/kg per 12 h i.p.) 1, 2, 6 or 12 h after SC trauma by T8-T9 spinal cord contusion, analyzing LP 24 h after injury at the lesion site by the lipid fluorescent products formation method. CsA significantly diminished LP to levels below control values after contusion (P < 0.05). The greater inhibition was observed when CsA was given during the first 6 h after injury, furthermore, animals showed a significant clinical improvement. Results show that CsA may be beneficial to injured tissue by inhibiting the levels of LP.

Animals↗
PubMed1998

Spontaneous long-term remyelination after traumatic spinal cord injury in rats.

The capability of the central nervous system to remyelinate axons after a lesion has been well documented, even though it had been described as an abortive and incomplete process. At present there are no long-term morphometric studies to assess the spinal cord (S.C.) remyelinative capability. With the purpose to understand this phenomenon better, the S.C. of seven lesionless rats and the S.C. of 21 rats subjected to a severe weight-drop contusion injury were evaluated at 1, 2, 4, 6, and 12 months after injury. The axonal diameter and the myelination index (MI = axolemmal perimeter divided by myelinated fiber perimeter) were registered in the outer rim of the cord at T9 SC level using a transmission electron microscope and a digitizing computer system. The average myelinated fiber loss was 95.1%. One month after the SC, 64% of the surviving fibers were demyelinated while 12 months later, only 30% of the fibers had no myelin sheath. The MI in the control group was 0.72 +/- 0.07 (X +/- S.D.). In the experimental groups, the greatest demyelination was observed two months after the lesion (MI = 0.90 +/- 0.03), while the greatest myelination was observed 12 months after the injury (MI = 0.83 +/- 0.02). There was a statistical difference (p < 0.02) in MI between 2 and 12 months which means that remyelination had taken place. Remyelination was mainly achieved because of Schwann cells. The proportion of small fibers (diameter = 0.5 micron or less) considered as axon collaterals, increased from 18.45% at 1 month to 27.66% a year after the contusion. Results suggest that remyelination is not an abortive phenomenon but in fact a slow process occurring parallel to other tissue plastic phenomena, such as the emission of axon collaterals.

Animals↗