A guide to difficult right ventricular pacemaker lead insertion.
Explore the source record for details and available documents.
Aged, 80 and over↗
Biomedical subjects
R De Palma
Publications and source records attributed to R De Palma.
Strategies and clinical outcome of 250 cycles of Preimplantation Genetic Diagnosis for single gene disorders.
BACKGROUND: We report on our experience with preimplantation genetic diagnosis (PGD) for single gene disorders (SGDs), from 1999 to 2004, describing strategies and overall clinical outcome of 250 cycles in 174 couples for 23 different genetic conditions. METHODS: PGD cycles included 15 for autosomal dominant, 148 for autosomal recessive and 19 for X-linked SGDs. In addition, 68 cycles of PGD for SGDs were performed in combination with HLA matching. The strategy in each case used an initial multiplex PCR, followed by minisequencing to identify the mutation(s) combined with multiplex PCR for closely linked informative markers to increase accuracy. Linkage analysis, using intragenic and/or extragenic polymorphic microsatellite markers, was performed in cases where the disease-causing mutation(s) was unknown or undetectable. RESULTS: In 250 PGD cycles, a total of 1961 cleavage stage embryos were biopsied. PCR was successful in 3409 out of 3149 (92.4%) biopsied blastomeres and a diagnosis was possible in 1849 (94.3%) embryos. Four hundred and twenty-seven embryos were transferred in 211 cycles, resulting in 71 pregnancies (33.6% per embryo transfer), including 15 biochemical pregnancies, six spontaneous miscarriages, two ectopic pregnancies, which were terminated, and nine pregnancies which are still ongoing. The remaining pregnancies were confirmed to be unaffected and went to term without complications, resulting in the birth of 35 healthy babies. CONCLUSIONS: Minisequencing for mutation detection combined with multiplex fluorescence PCR for linkage analysis is an efficient, accurate and widely applicable strategy for PGD of SGDs. Our experience provides a further demonstration that PGD is an effective clinical tool and a useful option for many couples with a high risk of transmitting a genetic disease.
Adult↗
Adoptive transfer of allogeneic Epstein-Barr virus (EBV)-specific cytotoxic T cells with in vitro antitumor activity boosts LMP2-specific immune response in a patient with EBV-related nasopharyngeal carcinoma.
BACKGROUND: The outcome of patients with nasopharyngeal carcinoma (NPC) presenting as advanced-stage disease or failing conventional radio-chemotherapy is poor. Thus, additional forms of effective, low-toxicity treatment are warranted to improve NPC prognosis. Since NPC is almost universally associated with Epstein-Barr virus (EBV), cellular immunotherapy with EBV-specific cytotoxic T lymphocytes (CTLs) may prove a successful treatment strategy. Patient and methods A patient with relapsed NPC, refractory to conventional treatments, received salvage adoptive immunotherapy with EBV-specific CTLs reactivated ex vivo from a human leukocyte antigen-identical sibling. EBV-specific immunity, as well as T-cell repertoire in the tumor, before and after immunotherapy, was evaluated. RESULTS: CTL transfer was well tolerated, and a temporary stabilization of disease was obtained. Moreover, notwithstanding the short in-vivo duration of allogeneic CTLs, immunotherapy induced a marked increase of endogenous tumor-infiltrating CD8+ T lymphocytes, and a long-term increase of latent membrane protein 2-specific immunity. CONCLUSIONS: Preliminary data obtained in this patient indicate that EBV-specific CTLs are safe, may exert specific killing of NPC tumor cells in vitro, and induce antitumor effect in vivo.
Adult↗
Analysis of the antigen specific T cell repertoires in HIV infection.
In addition to HIV infection, several acquired immunodeficiencies lead to depletion of CD4 lymphocytes. These include immunosuppression resulting from high dose cancer chemotherapy or induced to control graft rejection, as well as in autoimmune diseases. The consequence of this depletion is an increased susceptibility to opportunistic infections or the inability to control primary infection in the case of HIV infection. In all instances a full or partial immunoreconstitution is desirable. In order to monitor the cellular immune state of a patient, rational information cannot be simply derived from phenotypic quantification of T lymphocytes. Instead loss or recovery of CD4 cells should be monitored by defining the specificity, the function and the clonality of the relevant cell population. Several methods are now available for this type of investigation. Here we describe an approach for the definition of clonal heterogeneity of antigen specific CD4 lymphocytes, a parameter that may help monitor loss or reconstitution in acquired immunodeficiencies. As examples of antigen specific CD4 T cell responses we focused on Pneumocystis carinii and on cytomegalovirus, as prototypic opportunistic pathogens which are responsible for severe infections in AIDS and in other immunosuppressive conditions which arise for instance following transplantation. Specific CD4 T cell lines were generated from normal controls and from seropositives in order to select antigen specific lymphocytes. The cells were subsequently analyzed for clonal diversity according to TCR BV gene family usage and according to TCR CDR3 size heterogeneity (spectratyping).
AIDS-Related Opportunistic Infections↗
Identification of T cells responding to a self-protein modified by an external agent.
An interesting class of immune responses is that in which an environmental agent modifies a self-protein. Heparin induced thrombocytopenia (HIT) is associated with an antibody response in which the immunogen is a self-protein, platelet factor 4 (PF4), modified by an external agent, heparin. We tested the hypothesis that a T cell component exists in HIT, which like the humoral response, also requires the combination of heparin and PF4 to be activated. We identify here, a subset of T cells derived from a subject with severe HIT, which were expanded preferentially in 14-day in vitro cultures specifically in the presence of PF4:heparin complexes. A combination of T cell receptor spectratyping, CDR3 sequencing, and clonotype-specific probe hybridization were used to identify the responding T cells. The three BV17 T cell "clonotypes" thus identified had a CDR3 length of 10 amino acids, used BJ1.2, and displayed a conserved CDR3 sequence motif. These T cells are an example of a cellular response to environmentally altered self and are likely to be directly involved in HIT by functioning as T helper cells. The results are discussed in terms of the possible role of modification of antigen presentation by the external agent in this response.
Aged↗
Tat protein is an HIV-1-encoded beta-chemokine homolog that promotes migration and up-regulates CCR3 expression on human Fc epsilon RI+ cells.
Human basophils and mast cells express the chemokine receptor CCR3, which binds the chemokines eotaxin and RANTES. HIV-1 Tat protein is a potent chemoattractant for basophils and lung mast cells obtained from healthy individuals seronegative for Abs to HIV-1 and HIV-2. Tat protein induced a rapid and transient Ca(2+) influx in basophils and mast cells, analogous to beta-chemokines. Tat protein neither induced histamine release from human basophils and mast cells nor increased IL-3-stimulated histamine secretion from basophils. The chemotactic activity of Tat protein was blocked by preincubation of FcepsilonRI(+) cells with anti-CCR3 Ab. Preincubation of Tat with a mAb anti-Tat (aa 1-86) blocked the migration induced by Tat. In contrast, a mAb specific for the basic region (aa 46-60) did not inhibit the chemotactic effect of Tat protein. Tat protein or eotaxin desensitized basophils to a subsequent challenge with the autologous or the heterologous stimulus. Preincubation of basophils with Tat protein up-regulated the level of CCR3 mRNA and the surface expression of the CCR3 receptor. Tat protein is the first identified HIV-1-encoded beta-chemokine homologue that influences the directional migration of human FcepsilonRI(+) cells and the expression of surface receptor CCR3 on these cells.
Adult↗
Use of altered peptide ligands to modulate immune responses as a possible immunotherapy for allergies.
Allergies are dramatically increasing in prevalence, and the management of these diseases is a heavy burden on the health-care systems of developed countries. In recent years, many efforts have been made to improve the therapy of allergies and to develop new approaches for immunotherapy. Here we briefly review the use of peptides to modulate T-cell responses to allergens. We focus mainly on the possibility of using altered peptide ligands (APLs), i.e., peptides tailored on immunodominant T epitopes and bearing a single amino-acid substitution, as a tool to modulate immune responses to allergens. These peptides may be recognized by the specific T cells triggered by the agonist peptides, but they are unable to elicit T-cell responses; thus, they could be ideal candidates to modulate immune responses to allergens. The availability of these peptides could allow new approaches for immunotherapies.
Animals↗
Th1/Th2 lymphocyte polarization in asthma.
Asthma is a complex inflammatory disease of the lung characterized by variable airflow obstruction, bronchial hyperresponsiveness, and airway inflammation. Inflammation in asthma consists of airway infiltration by mast cells, lymphocytes, and eosinophils. There is accumulating evidence that CD4+ lymphocytes with a Th2-cytokine pattern play a pivotal role in the pathogenesis of asthma. These cells orchestrate the recruitment and activation of the primary effector cells of the allergic response (mast cells and eosinophils), through the release of cytokines such as IL-4, IL-5, and IL-13. Allergic inflammation is also implicated in airway epithelium changes, although the mechanisms by which inflammatory cells and, in particular, T cells interact with the epithelium are not completely clarified. This paper explores the role of T cells in the allergic inflammation of asthma.
Asthma↗
Coexistence of two functioning T-cell repertoires in healthy ex-thalassemics bearing a persistent mixed chimerism years after bone marrow transplantation.
Bone marrow transplantation (BMT) from an HLA-identical donor is an established therapy to cure homozygous beta-thalassemia. Approximately 10% of thalassemic patients developed a persistent mixed chimerism (PMC) after BMT characterized by stable coexistence of host and donor cells in all hematopoietic compartments. Interestingly, in the erythrocytic lineage, close to normal levels of hemoglobin can be observed in the absence of complete donor engraftment. In the lymphocytic lineage, the striking feature is the coexistence of immune cells. This implies a state of tolerance or anergy, raising the issue of immunocompetence of the host. To understand the state of the T cells in PMC, repertoire analysis and functional studies were performed on cells from 3 ex-thalassemics. Repertoire analysis showed a profound skewing. This was due to an expansion of some T cells and not to a collapse of the repertoire, because phytohemagglutinin stimulation showed the presence of a complex repertoire. The immunocompetence of the chimeric immune systems was further established by showing responses to alloantigens and recall antigens in vitro. Both host and donor lymphocytes were observed in the cultures. These data suggest that the expanded T cells play a role in specific tolerance while allowing a normal immune status in these patients.
Adolescent↗
Complexes of heparin and platelet factor 4 specifically stimulate T cells from patients with heparin-induced thrombocytopenia/thrombosis.
Heparin-induced thrombocytopenia with thrombosis (HITT) is associated with antibodies specific for complexes consisting of heparin and platelet factor 4 (PF4). Studies in individual patients with HITT have demonstrated immunoglobulin (Ig) class switching from IgM to the IgG or IgA isotypes. This transition is thought to require helper T cells, but no studies of the cellular or molecular basis of this process have yet been reported. To characterize T-cell involvement in HITT, peripheral blood mononuclear cells (PBMC) from two patients with classical HITT obtained shortly after the acute episode were restimulated with heparin:PF4 complexes, PF4 alone, heparin alone, and medium alone in the presence of autologous antigen-presenting cells (APC). Responding T cells were then examined using the technique of "spectratyping," in which sequences encoding CDR3 domains of individual V beta (BV) families are amplified and separated by gel electrophoresis. After 14 days in culture with antigen (heparin:PF4 complexes), but not after culture with PF4, heparin, or medium alone, patient cells, but not cells from normal subjects, preferentially expressed T-cell receptor (TCR)-containing beta chains of the BV 5.1 family. Nucleotide sequencing of BV 5.1 TCR CDR3 showed that each patient had a personal repertoire, but also shared a tetrapeptide motif (PGTG). These findings provide evidence that the humoral immune response associated with HITT is driven by helper T cells that presumably recognize peptides derived from PF4. Identification of a common beta-chain CDR3 motif in responding T cells from each of two patients suggests that a limited number of helper TCRs may be used to mount an antibody response to heparin:PF4 complexes. TCR spectratyping appears to offer a new way to examine the molecular basis of pathologic immune responses and may be useful in further studies of HITT and other immune-mediated hematologic disorders.
Aged↗
Use of antagonist peptides to inhibit in vitro T cell responses to Par j1, the major allergen of Parietaria judaica pollen.
Antigenic peptides with substituted side chains inhibit immune responses to a number of recall Ags from infectious agents in vitro. Here we show that the same strategy can be applied to peptides derived from a pollen protein, the major allergen of Parietaria judaica(Par j1), a plant responsible for most allergenic sensitization in the southern Mediterranean area. Three T cell lines responding to Par j1 protein were used to identify a stimulatory peptide. Two different monosubstituted altered peptide ligands (APL) were identified that bound to the HLA-DR of the responders, did not stimulate the T cell lines on their own, and decreased the response to subsaturating amounts of the unmodified stimulatory peptide. Most important, these APL were able to inhibit the response of these cell lines to intact Par j1 protein. A third monosubstituted peptide bound to the HLA-DR but did not show inhibitory activity. The two APL had a lower affinity than the unsubstituted peptide for the HLA-DR. The last two observations make MHC blockade an unlikely explanation for the observed effect. These results indicate the action of a specific peptide-mediated antagonism that may be useful in controlling the T cell component of an allergic response.
Allergens↗
Posttransplant human herpes virus 8 infection and seroconversion in a Kaposi's sarcoma affected kidney recipient transplanted from a human herpes virus 8 positive living related donor.
Explore the source record for details and available documents.
Adult↗
Restricted and conserved T-cell repertoires involved in allorecognition of class II major histocompatibility complex.
The nature of the alloreactive T-cell response is not yet clearly understood. These strong cellular responses are thought to be the basis of allograft rejection and graft-vs.-host disease. The question of the extent of responding T-cell repertoires has so far been addressed by cellular cloning, often combined with molecular T-cell receptor (TCR) analysis. Here we present a broad repertoire analysis of primed responder cells from mixed lymphocyte cultures in which two different DR1/3 responders were stimulated with DR3/4 cells. Repertoire analysis was performed by TCR spectratyping, a method by which T cells are analyzed on the basis of the complementarity-determining region 3 length of different variable region (V) families. Strikingly, both responders showed very similar repertoires when the TCR V beta was used as a lineage marker. This was not seen when TCR V alpha was analyzed. A different pattern of TCR V beta was observed if the stimulating alloantigen was changed. This finding indicates that alloreactive T cells form a specific repertoire for each alloantigen. Since conservation appears to be linked to TCR V beta, the question of different roles of alpha and beta chains in allorecognition is raised.
Clone Cells↗
Analysis of transcripts of genes located within the HLA-D region in B cells from an HLA-severe combined immunodeficiency individual.
The mRNA levels of LMP7, HLA-DMA, and HLA-DMB genes, all located within the HLA-D region, were analyzed in the "bare lymphocyte" line SJO, which had been shown to be characterized by a transcription defect of class II genes (DP, DQ, and DR). This was done using semiquantitative PCR amplification of cDNA generated from total RNA. The results show that the transcription of the LMP7 gene in SJO cells is equivalent to that in the control B-cell line Raji. In contrast, the HLA-DM gene transcripts were not present in the SJO cell line. This observation indicates that the promoter similarity between the classic class II genes and HLA-DM is sufficient for the SJO defect to extend to the DM loci.
Base Sequence↗
[Microparticulate aerosols and respiratory allergy].
The assessment of allergenic activity in submicronic particles could explain some unknown aspects of pollinosis pathogenesis. Twenty-five 0.5 discs have been obtained using a high volume sampler (Hi Vol Andersen) equipped with 0.3 micron Whatman paper filters. These discs have been challenged with a concentrated pool of sera of Parietaria allergic patients by RIA in order to evaluate the presence of allergenic activity on filters. Discs of non sampled filters and discs of sampled filters challenged with serum pool of patients sensitized to house dust mites were used as controls. The percentage of bound radioactivity was detected by gamma-counter. The radioactivity bound to sampled discs with Parietaria sera was 2.3 +/- 0.55 (Standard Deviation); radioactivity detected on control discs was comparable to background values detected by counter. These preliminary date might suggest that submicronic particles of Parietaria can retain some allergenic activity.
Air Pollutants↗
Kinetics of intravenous metoclopramide in patients with hepatic cirrhosis.
The pharmacokinetics of metoclopramide has been studied after acute IV administration to 12 patients with hepatic cirrhosis (6 with and 6 without ascites) and 6 control subjects. The elimination half-life was significantly longer in patients (11.4 h and 9.9 h in those with and without ascites, respectively, vs 6.4 h in controls). Total plasma clearance was significantly lower in patients (0.29 and 0.36 l.kg-1.h-1 vs 0.52 l.kg-1.h-1 in controls). The differences between patients with and without ascites did not reach statistical significance. Reduction of functional hepatic blood flow in cirrhotic patients is the probable cause of the observed alteration in metoclopramide kinetics.
Adult↗
Antigenic activity of nonpollen parts (leaves and stems) of allergenic plants (Parietaria judaica and Dactylis glomerata).
In patients with respiratory allergy to pollen it is common to correlate the onset, duration and intensity of clinical symptoms with the count of atmospheric allergenic pollen grains. Pollen counts, however, may not reflect the total airborne allergen exposure since previous data suggest that pollen allergens may also be carried in microaerosol suspensions. These microdroplets may penetrate deeply into the airways, where pollen grains are too large to penetrate, eventually inducing asthma. The origin of these allergenic aerosols is still uncertain. We investigated whether antigenic activity is present in vegetative parts of allergenic plants. We have used extracts from leaves and stems of Parietaria judaica and Dactylis glomerata to evaluate patients with allergic sensitization to pollen allergens of these plants (19 grass-sensitive patients and 23 Parietaria sensitive). By using skin prick testing and RAST to stem and leaf extracts other than pollen extracts we observed that most patients sensitive to grass or Parietaria pollen had small responses to extracts of stem or leaf. We conclude that allergenic components are present throughout most of Parietaria judaica and Dactylis glomerata plants, most highly concentrated in the pollen but present in the leaves with a trace in the stems.
Adolescent↗
Circadian variation in renal sodium and potassium handling in cirrhosis. The role of aldosterone, cortisol, sympathoadrenergic tone, and intratubular factors.
Renal sodium and potassium handling, plasma aldosterone and cortisol concentrations, and urine free norepinephrine excretion were determined every 4 h for 24 h in 15 cirrhotics (7 without ascites, group 1; 8 with ascites, group 2) and 7 healthy controls during controlled salt intake and recumbency. Renal sodium excretion was significantly reduced in group 2, whereas it exceeded threefold the salt intake in group 1. Its circadian rhythm was disrupted in both groups of patients. Significant inverse correlations with plasma aldosterone were found erratically in controls, never in group 1, and at every 4-h interval in group 2. In the latter, the indexes of tubular activity and effectiveness of aldosterone were also significantly increased. Urine norepinephrine excretion was never related to sodium excretion in either controls or patients; in group 2 it was directly correlated with glomerular filtration rate in many instances. The cortisol-related circadian rhythm of kaliuresis was retained only in group 1. The 24-h renal potassium excretion of controls and patients was comparable, in spite of the striking hyperaldosteronism, and the more than doubled contribution of aldosterone to kaliuresis shown in group 2. The influence of aldosterone on potassium excretion was also witnessed by the direct correlation between these variables found in group 1 and, when kaliuresis was corrected by the distal sodium delivery, group 2. Renal sodium handling in cirrhosis is altered even before ascites formation and compensated patients can undergo "spontaneous natriuresis." Aldosterone is the main cause of sodium retention in nonazotemic ascitic patients, while sympathoadrenergic hyperactivity may contribute to preserve renal perfusion. The influence of aldosterone on kaliuresis is enhanced, but renal potassium wasting in patients with ascites and hyperaldosteronism is prevented by reduced distal tubular availability of sodium.
Adult↗