Biomedical subjects

J A León

Publications and source records attributed to J A León.

16 recordsLinked to original sources

PubMed2006

[Intraoperative high frequency oscillatory ventilation in 2 children undergoing lung surgery].

Over the past 10 years, the application of high frequency oscillatory ventilation (HFOV) has been extended beyond the neonatal period. The technique is now used in various respiratory disease settings when conventional mechanical ventilation fails. Even though HFOV has become increasingly routine in some pediatric intensive care units, familiarity with it is still limited among anesthesiologists and surgeons and it is not often applied during surgery. We report our experience using HFOV during thoracic surgery on 2 pediatric patients, one aged 5 years and the other aged 1 month. The respective surgical procedures were to close a bronchopleural fistula and to obtain a lung biopsy in order to provide guidance for limiting therapeutic intervention. In both cases the procedure was performed without adverse effects and allowed medical interventions to be carried out. We conclude that it is possible to perform thoracic surgery in pediatric patients undergoing HFOV. This ventilation mode can be useful during surgery and teams that care for critically ill children should be familiar with the equipment.

Barotrauma↗

PubMed2004

HIV-infected children with moderate/severe immune-suppression: changes in the immune system after highly active antiretroviral therapy.

The objective of this study was to monitor the changes in the immune system of HIV-infected children with moderate or severe immunodeficiency after highly active antiretroviral therapy (HAART), comprising a follow-up study in 14 HIV-infected children on HAART at two time points separated approximately by 11.8 +/- 0.4 (9.9; 15.4) months. HIV-infected children had significantly lower TREC levels than the control group, but 1 year after HAART the levels increased significantly (P < 0.05). In contrast, viral load (VL) did not change significantly. A positive correlation between T cell receptor excision circle (TREC) levels and both CD4(+) T cell absolute counts (r = 0.558; P = 0.05) and percentages (r = 0.625; P = 0.030) was found. During follow-up on HAART, the percentages and absolute counts of naive CD4(+) and CD8(+) T cell subsets were increased significantly (P < 0.05). CD4(+) CD45RA(hi+) CD62L(+), CD4(+) CD45RA(+) and CD4(+) CD38(+) percentages, and the CD8(+) CD45RA(hi+) CD62L(+) counts reached similar values to the control group. Also, CD8(+) CD45RO(+) CD38(+) and CD8(+) CD45RO(+) percentages, and CD8(+) CD45RO(+) CD38(+) absolute counts (P < 0.05) decreased with respect to the baseline. Lymphoproliferative responses to pokeweed mitogen (PWM) before HAART were lower in HIV-infected children than the control group, but they recovered to normal levels after a year on HAART. Tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma production by PHA-activated peripheral blood mononuclear cells (PBMC) was lower before HAART (P < 0.001), but reached similar levels to the control group 1 year after HAART. In HIV-infected children IgG, IgG(1) and IgG(3) plasma levels decreased significantly after HAART. The immune system reconstitution induced by HAART in HIV-infected children seems to be the consequence of decreased immune system activation and naive T cell reconstitution, mainly of thymic origin.

Adolescent↗

PubMed2003

Recovery of T-cell subsets after antiretroviral therapy in HIV-infected children.

BACKGROUND: Variation of percentageCD4+ T cells may accurately reflects the kinetics of a comprehensive immune recovery independently of the antiretroviral (ART) regimen. To test this we have investigated the relationship among peripheral blood T-cell subsets with the variation of percentageCD4+ T cells during follow up in 49 HIV-infected children. METHODS: Children were divided into two groups according to the sign of slope percentageCD4+ T cell during follow up: Ps-group (positive slope) and Ns-group (negative percentageCD4 slope) indicative of immunological recovery or not, respectively. CD4+ and CD8+ T-cell subset percentages were examined by three-colour flow cytometry. RESULTS: We found higher memory CD4+ and CD8+ T-cell percentages in the Ns-group than in the Ps-group, and inversely, higher naive CD4+ and CD8+ T cells in the Ps-group than in the Ns-group. CD4+ and CD8+ subsets in the Ps-group expressed higher levels of CD38+ and lower levels of HLA-DR+ compared with the Ns-group. We found a very strong positive correlation among the slope of percentageCD4+, CD4+ CD38+, whereas a negative correlation among the slope of percentageCD4+, the CD8+ CD28+ CD57+ and CD8+ CD57+ T-cell subsets. CONCLUSION: Recovery of the CD4+ T-cell percentage induced by ART reflects a reduction in the chronic immune activation and a measurable reconstitution of the immune system and depends on naive CD4+ T cells.

Antiretroviral Therapy, Highly Active↗

PubMed2002

Dynamics of progression markers in a non-study population of human immunodeficiency virus-1 vertically infected infants with different antiretroviral treatments.

UNLABELLED: Treatment with highly active antiretroviral therapy (HAART) has been shown to modify viral replication dynamics and lead to a significant recovery of CD4+ T-cells. A retrospective multicentre observational study was performed in a non-study population of 151 HIV-1-infected children, categorized into four groups according to therapy: untreated (NT), on monotherapy (MT) with a nucleoside inhibitor, on combination therapy (CT) with two nucleoside inhibitors, and on HAART, protease inhibitor containing regimens, to assess the "real-life" effectiveness of these different therapies on plasma viral load (VL) and CD4+ T-cells. VL was quantified using a standard molecular assay. CD4+ and CD8+ T-cells subsets were determined by flow cytometry. The HAART group showed the highest relative proportion (RP) of increases in 5, 10, 15 and 20% of CD4+ T-cells over baseline, and the earliest fall-off of VL (0.5, 1, 1.5 and 2 log10 copies ml-1). The RP of the fall-off of 0.5, 1, 1.5 and 2 log10 VL below baseline was 3-fold higher in HAART group than in the MT and CT groups. However, no differences were found among the groups of treated children in reaching undetectable VL. CONCLUSION: A better evolution of VL and CD4+ T-cells was evident in children on HAART, indicating a positive effect on the immune system and clinical status, inhibiting HIV-1 replication and enabling the recovery of CD4+ T-cell counts.

Anti-HIV Agents↗

PubMed2002

Impact of antiretroviral protocols on dynamics of AIDS progression markers.

AIMS: To assess the "real life" effectiveness of different antiretroviral therapies (ART). METHODS: A retrospective multicentre observational study in 150 HIV-1 vertically infected children on the progression to AIDS (study A), and in 61 HIV-1 infected children on the evolution of the most relevant markers of progression (study B). All children were categorised into four groups: untreated (NT); on monotherapy (MT); on combination therapy (dual-ART); and on potent ART (HAART). RESULTS: No child in the HAART group progressed to AIDS, whereas 14 children in the NT and seven in the MT groups progressed to AIDS, respectively, the differences being statistically significant. There was a mean increase of 8 units of %CD4+ per year; this was greater in the HAART group than in the other groups. The mean decrease in viral load was 0.65 log(10) copies/ml per year; this was greater in the HAART group than in the NT and MT groups. The HAART group had the lowest probability of returning to baseline %CD4+ and viral load. CONCLUSION: Potent ART had the greatest protective effect against progression to AIDS in this observational study.

Acquired Immunodeficiency Syndrome↗

PubMed2001

[Relationship between T-cells subsets and prognostic markers in HIV-1-infected children].

BACKGROUND: To investigate the relationship between peripheral blood T-cell subsets and both CD4+ T-cell percentage and viral load (VL) in HIV-1-infected children. PATIENTS AND METHOD: We studied 50 HIV-1-infected children on antiretroviral therapy. T-cell subsets were determined by flow cytometry. The VL was quantified using standardized molecular methods. RESULTS: Memory (CD45RO+), activated memory (CD45RO+HLA-DR+) and CD45RA-CD62L+ (memory cells expressing L-selectin) CD4+ and CD8+ T-cells correlated positively with the VL and negatively with the percentage of CD4+ T-cells. Inversely, naive CD4+ and CD8+ T-cells (CD45RA+CD62L+) correlated positively with the percentage of CD4+ T-cells and negatively with the VL. HLA-DR+, CD38+ or HLA-DR+CD38+CD4+ and CD8+ T-cells correlated also positively with the VL and negatively with the percentage of CD4+ T-cells (with the exception of CD4+CD38+ which did not show any association with the VL). CD8+CD28+ T-cells correlated positively with the percentage of CD4+ T-cells and negatively with the VL, whereas CD8+ CD57+ and CD8+CD28-CD57+ exhibited an opposite association. CONCLUSIONS: Our data suggest a relationship between the different lymphocyte subsets (memory, naïve, activated and effector T-cells) and the most commonly used markers in clinical practice, namely the viral load and the CD4+ T-cell percentage. Some of these subsets may be useful to determine the virologic and immunologic status in HIV-1-infected children.

Biomarkers↗

PubMed2001

Naïve and memory CD4+ T cells and T cell activation markers in HIV-1 infected children on HAART.

The objective of this study was to investigate the relationship between peripheral blood CD4+ T cell subsets and routine viro-immunological markers in vertically HIV-1-infected children undergoing highly active antiretroviral therapy (HAART). CD4+ and CD8+ T cell subsets were examined by three-colour flow cytometry. Plasma viraemia was quantified by a standardized molecular assay. A negative correlation between the %CD4+ T cells and both viral load and the %CD8+ T cells was observed. A strong positive correlation between the %CD4 T cells and naïve, CD38+ and non-activated CD4+ T cell subsets was found, whereas the %CD4 T cells correlated negatively with the numbers of memory, activated and memory-activated CD4+ T cell subsets. Elevated percentages of CD8 T cells were associated with increased memory and CD4+ CD62L-T cell subsets, whereas the naïve and CD4+ HLA-DRCD38+ subsets negatively correlated with the CD8%. Co-expression of CD62L on memory CD4+ cells and high expression of HLA-DR (but not of CD38) were associated with high viral load. No association between viral load and naïve CD4+ T cells was observed. Specific CD4+ T cell subsets may be more informative than routine surrogate markers in defining the evolution of HIV infection and immune reconstitution in children.

ADP-ribosyl Cyclase↗

PubMed2000

Comparative statics of joint reproductive allocation.

We perform a perturbation analysis (comparative statics) of how optimal reproductive effort and per offspring investment are jointly affected by different selective factors. The factors considered are: (1) mortality sources, classified according to affected stage (juvenile or adult) and to its nature (avoidable or unavoidable), and (2) resource (energy) availability for the adult individual. The joint approach reveals both direct and indirect effects of each selective pressure. These interactive effects spring from the nonlinearity of reproductive expenditure, separated into a part devoted to endowing offspring (provisioning cost) and another part invested to make reproduction possible (requisite cost). The latter is envisioned as a reverse sigmoid function of fecundity (most models, so far, have considered only the first kind of cost). The indirect effects have the consequence of enlarging the class of selective pressures that can induce changes of offspring size and clutch size, as compared with current explanations. So, they illuminate new causes for some effects, and show new effects for some well-known selective causes. Several joint patterns in the two variables, shown by animals and plants in the field, can thus be given more appropriate interpretations than traditional, piecewise, ones.

Animals↗

PubMed2000

Chronic obstructive pneumonia caused by a vertebral body osteophyte.

Osteophytes associated with spondylosis have been implicated as a cause of multiple extraspinal manifestations. Symptoms are more likely to occur with the large osteophytes associated with diffuse idiopathic skeletal hyperostosis. In the thoracic region, osteophytes have been reported infrequently as a cause of extraspinal complications. We report a case in which an anterior thoracic vertebral osteophyte was responsible for chronic obstructive pneumonia due to obstruction of the right main stem bronchus. The patient's condition improved considerably after surgical resection of the compressing thoracic osteophyte.

Aged↗

PubMed1999

[Dynamics of immunoglobulin production in non infected children born from HIV-1 infected mothers: effect of zidovudine].

BACKGROUND: To evaluate the possible effect of zidovudine (ZDV) on inmunoglobins production in infants born to HIV-1 infected women. SUBJECTS AND METHODS: We have studied the immunoglobulins serum levels in 57 non-infected children born to HIV-infected mothers. The children were divided into two groups: group A, 28 children born to HIV-1 infected mothers that received ZDV on protocol 076 conditions, and group B, 29 children born to mothers that did not receive anti-HIV-1 drugs. Quantification of serum IgG, IgA and IgM was performed by nephelometric techniques. RESULTS: The median time to reach normal IgA values at 12 months, was 25.57 months (confidence interval [CI] 95%: 22.01-29.12) in the children of group A and 12.67 months (CI 95%: 9.90-15.44) in the children of group B (p = 0.01). The median time to reach normal IgM values at 12 months was 15.93 months (CI 95%: 15.21-16.65) in group A children versus 11.20 months (CI 95%: 8.51-13.89) in group B (p = 0.11). The median time to reach normal IgG values at 12 months was 19.67 months (CI 95%: 13.12-16.22) in group A children versus 12.73 months (CI 95%: 11.16-14.30) in group B (p = 0.05). The normal IgA levels were reached 2.36 (CI 95%: 1.16-4.81) times later in group A than in group B children (p = 0.02), whereas normal IgG levels were reached 1.88 (CI 95%: 0.94-3.78) times later in group A than in group B of children. CONCLUSIONS: Our results indicate that treatment of pregnant mothers with ZDV clearly affect the ability of their newborns to produce inmunoglobulins, which may have important practical implications for their vaccination protocols.

Anti-HIV Agents↗

PubMed1999

Correlation of viral load and CD8 T-lymphocytes with development of neurological manifestations in vertically HIV-1-infected infants. A prospective longitudinal study.

To assess the predictive power of immunological and virological markers for the development of neurological syndromes, 39 HIV-1-infected infants with a mean age of 4.05+/-0.5 months and without neurological manifestations at enrolment were studied. They had neither been previously treated with antiretroviral therapy, nor had their mothers been given such treatment during pregnancy. They were routinely assessed for signs of neurological impairment during follow-up (19.54+/-3.37 months). Cox regression analysis was used to evaluate the risk of appearance of neurological signs, associated to viral load and T-lymphocyte subsets. A HR > 1 for viral load, and <1 for CD8+, but not for CD4+T-lymphocyte percentage, was observed, indicating that higher viral load and lower CD8+ T-lymphocytes percentages are risk factors for developing neurological signs. By applying the Kaplan-Meier method we found that infants with viral load > 5 1og10 copies/ ml or <20% CD8+T lymphocyte had higher relative risk for developing neurological impairment than those with these two parameters below or above these values, respectively. Finally, CD8+ T lymphocyte had a stronger prognostic value to predict neurological manifestations than viral load. Our data strongly suggest that in the early postnatal period viral load and CD8+ percentages are useful markers in predicting neurological impairment. To our knowledge, this is the first time that CD8+ T-lymphocyte levels are related to development of neurological disorders in AIDS.

AIDS Dementia Complex↗

PubMed1992