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Biomedical subjects

A M Ortiz

Publications and source records attributed to A M Ortiz.

16 recordsLinked to original sources
PubMed2006

Evaluation of a multiplex PCR method to detect enteroaggregative Escherichia coli.

Enteroaggregative Escherichia coli (EAEC) has been implicated in sporadic diarrhea in children and adults and has been identified as the cause of several outbreaks worldwide. The HEp-2 test remains the gold standard for identification of this pathotype. A 60-65 MDa plasmid encodes the aggregative adherence fimbriae (AAF/I and AAF/II), a transcriptional activator (aggR gene), the enteroaggregative heat-stable enterotoxin EAST1 (astA gene) and a cytotoxin (Pet). The standard assay for EAEC is performed only in research laboratories, because it is expensive, labor intensive and time-consuming. The Polymerase Chain Reaction (PCR) offers the possibility of rapid diagnosis. In the current study, a multiplex PCR assay which checks aggR and astA genes was designed. Eigthy-eight E. coli strains, isolated from children with acute diarrhea in Mendoza, Argentina, were characterized by the reference method (HEp-2 assay), and by aggR-astA PCR. A strong correlation between the presence of the specific marker aggR and the reference test was found. The astA gene had a similar distribution between aggregative and localized strains, indicating that this gene could not be considered as a marker of EAEC. We conclude that aggR may be used to identify EAEC, using the PCR method as a screening test.

Bacterial Adhesion↗
PubMed2005

Influence of the kidney histology at the time of donation on long term kidney function in living kidney donors.

Living donation is the best choice for kidney transplantation, obtaining long-lasting good results for the recipient. Some concern still remains regarding the donor's long-term health. Kidney biopsy was routinely performed in our donor population at the time of donation many years ago. We found the existence of morphological kidney disease in those samples, in spite of normal clinical evaluations before donation. We attempted to correlate those abnormalities with long-term clinical outcomes. Donors were at least 10 years after surgery. A medical interview, including the SF-36 Health Survey, laboratory evaluation, and ambulatory blood pressure monitoring was performed on 27 donors meeting the inclusion criteria. Two donors had died after donation from unrelated causes with no known nephropathy. Histological analysis showed abnormalities in 16 of 29 donors. We found an increased prevalence of hypertension compared to the general population. Interestingly, there was no proteinuria in the donor population, and none developed clinical nephropathy. All subjects felt emotionally rewarded with donation, stating that their lives had no limitations. Our results suggest that kidney biopsy is neither necessary nor useful prior to donation because, although many donors had morphological kidney disease, none developed clinical nephropathy in the long term.

Blood Pressure Monitoring, Ambulatory↗
PubMed2005

Use of FTY 720 and ICAM-1 antisense oligonucleotides for attenuating chronic renal damage secondary to ischemia-reperfusion injury.

INTRODUCTION: Chronic allograft nephropathy is the main cause of graft loss. Although many factors are involved in its development, ischemia-reperfusion injury has received increasing attention as a risk determinant. In a previous study of syngeneic renal transplantation and ischemia, we demonstrated a protective effect of acute damage by FTY 720 and antisense oligonucleotides of ICAM-1 (Oligos). The purpose of the current study was to evaluate the impact of these agents on the development of chronic graft damage in the same model. METHODS: Lewis rat were used as donors and recipients. The harvested left kidney was kept in Collins solution for 2 hours. Recipient animals received treatment with FTY 720 or Oligos or saline. At 12 and 36 weeks after transplantation, creatinine clearance, GFR, proteinuria, and arterial blood pressure were recorded. Tissue from some animals were submitted for histological studies and quantification of mRNA TGF-beta1. RESULTS: All groups showed decreased levels of GFR and creatinine clearence, but only the untreated animals showed significant deterioration compared to the pretransplant values (0.53 +/- 0.24 versus 0.21 +/- 0.24 at 36 weeks respectively; P < .05). Proteinuria was also significant in control animals at 36 weeks. Blood pressure showed a moderate increase in all groups. Histological analysis showed that treated animals had fewer signs of chronic damage according to the Banff score. All groups displayed slight increases in TGF-beta1 without differences among them. CONCLUSIONS: In this model the use of FTY or antisense oligonucleotides of ICAM-1 were associated with less functional and morphological evidence of chronic graft damage secondary to an ischemia-reperfusion injury.

Animals↗
PubMed2003

Induction immunosuppressive therapy stratified according to risk categories in renal transplantation.

BACKGROUND: Immunosuppressive therapy is critical during the induction phase for it directly affects graft outcome. Many centers use uniform regimens, although not all patients represent similar risks. The purpose of this study was to evaluate a prospective protocol of immunosuppression according to 2 significant risks in kidney transplant: acute rejection (AR) and delayed graft function (DGF). METHODS: This study included 35 patients (group I) stratified before starting the immunosuppression as follows: (1) standard risk, (2) increased risk of AR, and (3) augmented risk of DGF. Standard risk patients were treated with Cyclosporine (CsA) and Prednisone (Pred) (n = 18). Patients with increased risk of AR were treated with CsA plus Pred plus Mycophenolate Mofetil (n = 4) or sequential induction with antithymocyte globulin (n = 5). Patients with augmented risk of DGF were started on sequential induction with late inception of CsA (n = 8). Comparisons were made with a series of 20 patients (group II) who received a uniform regimen including CsA plus Pred plus Azathioprine. RESULTS: AR and DGF rates were 6% and 16% for group I versus 39% and 39% for group II (P =.01 and P =.1, respectively). Serum creatinine values at 30 and 360 days were 1.43 +/- 0.45 and 1.29 +/- 0.40 in group I and 1.99 +/- 1.05 and 1.60 +/- 0.42 in group II (P <.05 for each comparison). Adverse effects, graft survival, and average costs were similar in both groups. CONCLUSION: The use of differentiate protocols was associated with better graft function and a reduced frequency of AR and DGF. Although 50% of patients required sequential or triple-drug induction, the adverse events and costs were similar. These results encourage the use of individualized immunosuppression.

Adult↗
PubMed2003

Prevention of renal ischemic reperfusion injury using FTY 720 and ICAM-1 antisense oligonucleotides.

BACKGROUND: Renal damage secondary to ischemia-reperfusion injuries (I-R) is frequent in organ transplantation and adversely affects the graft survival. An important component of this damage is caused by initial adhesion of neutrophils and lymphocytes to endothelial cells. FTY 720, which induces lymphopenia, has previously been shown to display protective effects in models of I-R. The purpose of the present study was to evaluate the combination of FTY 720 and intracellular adhesion molecule and ICAM-1 antisense oligonucleotides (AS-oligos), an agent designed to block the adhesion process. METHODS: Sprague-Dawley rats underwent syngenic kidney transplantation after donor kidneys had been preserved in cold solution for 2 hours. The treatment groups included: (1) FTY 720 (1 mg/kg) before reperfusion, (2) AS-oligos (2 mg/kg) during kidney perfusion, and (3) the combination of FTY 720 and AS-oligos. All animals were followed daily after transplantation; some were sacrificed on the second day for histologic analysis. RESULTS: All treated groups showed a maximal serum creatinine that was significantly less than the control (group 1: 2.76 +/- 1.4, group 2: 2.44 +/- 2.05, group 3: 1.51 +/- 0.42, and control: 4.04 +/- 0.5; P <.01) and returned to the basal value earlier. Also, treated animals showed less histologic stigmata of acute tubular damage. FTY 720 and AS-oligos used in combination showed a mild additive effect. CONCLUSIONS: The use of FTY 720 and/or AS-oligos significantly prevents functional renal damage secondary to I-R, displaying a mild additive effect in this model. Both agents offer the advantage of use during the donor and the graft operations.

Analysis of Variance↗
PubMed2000

Cyclosporin A inhibits CD69 expression induced on synovial fluid and peripheral blood lymphocytes by interleukin 15.

OBJECTIVE: To study the modulation of CD69 expression on peripheral blood (PB) and synovial fluid (SF) lymphocytes by interleukin 15 (IL-15) and several other cytokines and chemokines widely detected in the rheumatoid microenvironment. The effect of cyclosporin A (CSA) or methotrexate (MTX) in the cytokine mediated regulation of CD69 was analyzed. METHODS: CD69 expression on lymphocytes was assessed by flow cytometry after incubation with different cytokines, chemokines, phorbol myristate acetate, or calcium ionophore in the presence or absence of CSA, MTX, or both. The effect of IL-15 and SF supernatants in maintaining CD69 expression on SF lymphocytes was also assessed. IL-15 levels in SF supernatants were measured by ELISA. RESULTS: IL-15 induced the greatest upregulation of CD69 expression on PB lymphocytes in a time and dose dependent manner. IL-15 was able to maintain a high CD69 expression on SF lymphocytes. SF supernatants from rheumatoid arthritis (RA), which contain significant amounts of IL-15, also reversed the CD69 downregulation of SF lymphocytes in culture. CSA, but not MTX, inhibited the CD69 upregulation mediated by IL-15 both in PB and SF lymphocytes. CONCLUSION: IL-15 appears to be responsible, at least in part, for the high CD69 expression on lymphocytes from the rheumatoid microenvironment. Consistent with the virtual absence of lymphocyte derived cytokines in RA synovium, the prevention of IL-15 mediated CD69 upregulation on lymphocytes may explain the effect of CSA in the treatment of RA.

Antigens, CD↗
PubMed1999

[Severe and recent hyponatremia and hypokalemia associated to the use of hydrochlorothiazide, enalapril and citalopram. Clinical case].

We report a 72 years old hypertensive female, treated with enalapril 10 mg/day and hydrochlorothiazide 25 mg/day during three years. She presented a depressive disorder and cytalopram was prescribed in a dose of 10 mg/day. Two weeks before admission, a serum electrolyte analysis disclosed normal results and the cytalopram dose was increased to 20 mg/day. The patient was admitted with a hyponatremic encephalopathy with a plasma sodium of 100 mEq/L and a plasma potassium of 2.0 mEq/L. Cytalopram, enalapril and hydrochlorothiazide were discontinued, hypertonic NaCl and KCl were administered. The patient had a favorable evolution with a remarkable improvement of her symptoms.

Aged↗
PubMed1986

Maudsley reactive and non-reactive rat strains: differential performance in a conflict task.

Based on open field defecation rates, distinct strains of Maudsley rats have been identified. The Maudsley Reactive strains exhibit high levels of open field defecation, while the Maudsley Non-Reactive strains exhibit low levels of open field defecation. This difference in open field behavior has been interpreted as an indicator of "emotionality." The present studies were designed to compare the performance of two Maudsley strains, MR/Har and MNRA/Har, in the conditioned suppression of drinking (CSD) paradigm, another "model" behavior for the study of emotionality and/or anxiety in animals. In daily 10-minute sessions, water-deprived rats were trained to drink from a tube that was occasionally electrified (0.5 mA), electrification being signalled by a tone. In this procedure, MNRA/Har rats accepted significantly more shocks than did MR/Har rats. This difference between MR/Har and MNRA/Har strains, initially somewhat slight, became quite impressive over weeks of repeated testing. Although present in both male and female subjects, this strain difference was more prominent in the males. Thus, the MR/Har and MNRA/Har rat strains, bred originally for their differences in open field behavior, also differ markedly in their performance in the CSD paradigm. These findings suggest that the Maudsley rat strains may represent a useful genetically-based "animal model" for the study of emotionality and/or anxiety.

Animals↗
PubMed1985

[Secretin and pancreatic secretion in iron absorption].

Iron absorption in dogs without pancreatic secretion was studied measuring the percentage of radioactivity retained in red cells. Two groups were treated con 59Fe (5 microCi), given in the stomach: one group control and other undergoing pancreatic duct ligation. Increased absorption was observed in the last group. The influence of secretion on iron absorption, after administration of 60 mg of Fe (as ferrous sulphate solution pH 4.5), was also studied in three groups of dogs, treated with 18 Clinical Units of secretin. In one group, the pancreatic secretion was extracted from intestine by putting a catheter in the pancreatic duct. In the other two, the pancreatic duct remained normal, one with and other without the iron dose (control). A possible inhibitory effect of secretin on iron absorption was observed. Plasma Iron values remained without changes one hour after the iron administration, as well as TIBC, % saturation and transferrin values.

Animals↗
PubMedDate not supplied

The presence of nicotinamide adenine dinucleotide-independent Haemophilus paragallinarum in México.

Two isolates of Haemophilus paragallinarum were obtained from a layer chicken in Mexico. The isolates were confirmed as H. paragallinarum by polymerase chain reaction and conventional biochemical identification. The isolates were nicotinamide adenine dinucleotide (NAD) independent-growing on blood agar without the need of a nurse colony as well as on a complex medium that lacked both NAD and chicken serum. Both isolates were pathogenic, causing the typical clinical signs of infectious coryza in susceptible chickens. One isolate was Page serovar B/Kume serovar B-1 and the other isolate was Page serovar C/Kume serovar C-2. The isolates were associated with a field outbreak that involved an egg drop of 20% over a 3-wk period and a doubling of weekly mortality (from 0.1% to 0.2%). This is the first report of NAD-independent H. paragallinarum outside South Africa and is the first time that NAD-independent H. paragallinarum of serovar B has been reported.

Animals↗
PubMedDate not supplied

Increased serum levels of interleukin-15 in rheumatoid arthritis with long- term disease.

OBJECTIVE: To study the serum levels of IL-15 in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), seronegative spondyloarthropathies (SSd) and healthy donors. METHODS: The IL-15 serum levels were measured by ELISA in sera from 50 RA patients, 30 patients with SLE, 30 patients with SSd and 30 healthy donors. In RA patients, several clinical and demographic parameters were also obtained at the time of sample collection. IL-15 levels were compared in different RA subpopulations (positive or negative rheumatoid factor [RF], long term or recent onset disease, high or low disease activity). In addition, the possible association with other demographic and clinical parameters (gender, age, disease duration, etc) was also analysed. RESULTS: RA patients had significantly higher serum levels of IL-15 (102.4 +/- 150 pg/ml; p = 0.0001) than SLE patients (9.8 +/- 15.3 pg/ml), SSd patients (7.9 +/- 14.6 pg/ml) and healthy donors' (5.2 +/- 11.6 pg/ml). RA patients with a disease evolution less than 2 years showed lower IL-15 levels (33.7 +/- 62.2 pg/ml) than those with long-term disease (152.4 +/- 64.6 pg/ml; p = 0.004). In addition, a significant correlation between IL15 in serum and the number of disease-modifying antirheumatic drugs (DMARDs) prescribed was detected in RA patients (r = 0.42; p = 0.002). No association between IL-15 levels and age, gender, RF or disease activity was observed in this group. CONCLUSION: IL-15 is elevated in RA patients, specially in those with long term disease, compared to other rheumatic disorders. This finding supports that IL-15 is involved in the perpetuation of RA synovitis.

Aged↗
PubMedDate not supplied

The immunosuppressive effect of Mycoplasma meleagridis on nonreplicating antigens.

The humoral responses of Mycoplasma meleagridis-free and -infected turkeys were compared following primary and secondary antigenic stimulation with inactivated Salmonella pullorum or dinitrophenyl-bovine gamma globulin. The mycoplasma-infected groups had significantly lower antibody responses to both antigens. The suppression was more evident in the secondary response. The results suggest that the immune response in turkeys infected with M. meleagridis is similar to that of bursectomized chickens: the ability of chickens to synthesize immunoglobulin G is affected more readily than the ability to synthesize IgM.

Agglutination Tests↗
PubMedDate not supplied

Suppression of the humoral immune response to inactivated Newcastle disease virus by Mycoplasma meleagridis in the Turkey.

Groups of Mycoplasma meleagridis-free and -infected turkeys were vaccinated against Newcastle disease virus (NDV) at 5 and 8 weeks of age. The two groups did not differ significantly in antibody response to NDV as measured by the hemagglutination-inhibition test when a live vaccine (TCND) was used, but the two groups differed significantly when an inactivated vaccine was used; titers were higher in the mycoplasma-free group in both primary and secondary responses. The difference between responses of the mycoplasma-free and -infected groups to inactivated and live NDV was explained by a current hypothesis about the ontogeny of B-cell differentiation in the bursa of Fabricius and by its interference by M. meleagridis.

Animals↗