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Biomedical subjects

J M Wilson

Publications and source records attributed to J M Wilson.

At least 235 records · Page 13Linked to original sources
PubMed1996

Psychosocial adjustment and educational outcome in adolescents with a childhood diagnosis of attention deficit disorder.

OBJECTIVE: To conduct a retrospective follow-up study of psychosocial adjustment and educational outcome in adolescents with a childhood diagnosis of attention deficit disorder (ADD) and a group of clinical controls. METHODS: Groups included male and female subjects aged 14 to 18 years at time of follow-up with childhood diagnosis of ADD (cases; n = 48) versus other neurodevelopmental disorders (clinical controls; n = 37). Cases were also subdivided based on the presence of conduct disorder (CD) at follow-up. All groups were compared on measures of academic performance, self-esteem, behavior, alcohol and substance use, and adaptive functioning. RESULTS: Cases had significantly lower academic performance and poorer social, emotional, and adaptive functioning than clinical controls. Cases with CD had significantly lower academic performance, greater externalizing behaviors and emotional difficulties, and lower adaptive functioning than cases without CD. Cases with CD fared worse than clinical controls on self-report measures of behavior, socialization skills, and alcohol and substance use. CONCLUSIONS: These academic and psychosocial problems in adolescents with a childhood diagnosis of ADD suggest potential long-term ramifications for vocational and psychological functioning into adulthood. In addition, the presence of CD in some of these cases during adolescence appears to further increase the risk for maladaptive outcome.

Achievement↗
PubMed1996

Transduction with recombinant adeno-associated virus for gene therapy is limited by leading-strand synthesis.

Adeno-associated virus is an integrating DNA parvovirus with the potential to be an important vehicle for somatic gene therapy. A potential barrier, however, is the low transduction efficiencies of recombinant adeno-associated virus (rAAV) vectors. We show in this report that adenovirus dramatically enhances rAAV transduction in vitro in a way that is dependent on expression of early region 1 and 4 (E1 and E4, respectively) genes and directly proportional to the appearance of double-stranded replicative forms of the rAAV genome. Expression of the open reading frame 6 protein from E4 in the absence of E1 accomplished a similar but attenuated effect. The helper activity of adenovirus E1 and E4 for rAAV gene transfer was similarly demonstrated in vivo by using murine models of liver- and lung-directed gene therapy. Our data indicate that conversion of a single-stranded rAAV genome to a duplex intermediate limits transduction and usefulness for gene therapy.

Adenovirus E1 Proteins↗
PubMed1996

Role of viral antigens in destructive cellular immune responses to adenovirus vector-transduced cells in mouse lungs.

Adenoviruses missing E1 have been used as gene delivery vectors to the lungs for the treatment of cystic fibrosis. Transient expression of the recombinant gene and the development of inflammation have been two major limitations to the application of first-generation recombinant adenoviruses for gene therapy. Studies with mouse models of liver- and lung-directed gene therapy suggested that CD8+ cytotoxic T lymphocytes (CTLs) are effectors that contribute to extinction of transgene expression. The precise antigens responsible for activation of CTLs have not been identified. In this study, we examine the relative contributions of viral proteins versus the transgene product to the activation of CTLs which eliminate transgene-containing cells in mouse lungs. Instillation of a lacZ-expressing virus into the lungs of C57BL/6 mice elicited CTL responses to both viral proteins and the transgene product, beta-galactosidase, which collectively contribute to loss of trans-gene expression in mouse airways. Similar results were obtained in two experimental models in which the animals should be tolerant to the transgene, i.e., lacZ virus delivered to an animal transgenic for lacZ and a virus expressing the liver-specific enzyme ornithine transcarbamylase administered to the lungs of various strains of immune-competent mice. These data confirm the hypothesis that CTLs specific for viral antigens contribute to the problem of transgene instability in mouse lungs and indicate that CTLs specific for transgene product alone cannot account for the observed problem.

Adenoviridae↗
PubMed1996

Biology of adenovirus vectors with E1 and E4 deletions for liver-directed gene therapy.

Recombinant adenoviruses with E1 sequences deleted efficiently transfer genes into a wide variety of target cells. Antigen- and nonantigen-specific responses to the therapy lead to toxicity, loss of transgene expression, and difficulties with vector readministration. We have created new cell lines that allowed the isolation of more disabled adenovirus vectors that have both E1 and E4 deletions. Studies with murine models of liver-directed gene therapy indicated that the E1- and E4-deleted vector expresses fewer virus proteins and induces less apoptosis, leading to blunted host responses and an improved safety profile. The impact of the E4 deletion on the stability of vector expression was confounded by immune responses to the transgene product, which in this study was beta-galactosidase. When transgene responses were eliminated, the doubly deleted vector was substantially more stable in mouse liver than was the E1-deleted construct. These studies indicate that adenovirus vectors with both E1 and E4 deletions may have advantages in terms of safety and efficacy over first-generation constructs for liver-directed gene therapy.

Adenovirus E1 Proteins↗
PubMed1996

Recruitment of wild-type and recombinant adeno-associated virus into adenovirus replication centers.

Replication of a human parvovirus, adeno-associated virus (AAV), is facilitated by coinfection with adeno-virus to provide essential helper functions. We have used the techniques of in situ hybridization and immunocytochemistry to characterize the localization of AAV replication within infected cells, Previous studies have shown that adenovirus establishes foci called replication centers within the nucleus, where adenoviral replication and transcription occur. Our studies indicate that AAV is colocalized with the adenovirus replication centers, where it may utilize adenovirus and cellular proteins for its own replication. Expression of the AAV Rep protein inhibits the normal maturation of the adenovirus centers. Similar experiments were performed with recombinant AAV (rAAV) to establish a relationship between intranuclear localization and rAAV transduction. rAAV efficiently entered the cell, and its genome was faintly detectable in a perinuclear distribution and was mobilized to replication centers when the cell was infected with adenovirus. The recruitment of the replication-defective genome into the intranuclear adenovirus domains resulted in enhanced transduction. These studies illustrate the importance of intracellular compartmentalization for such complex interactions as the relationship between AAV and adenovirus.

Adenoviridae↗
PubMed1996

Transient subversion of CD40 ligand function diminishes immune responses to adenovirus vectors in mouse liver and lung tissues.

First-generation adenovirus vectors will have limited application in gene therapy for chronic diseases because of destructive host immune responses. Important immune effectors include CD8+ T cells, which mediate target cell destruction and ablate transgene expression, and B cells, which produce neutralizing antibodies that block effective readministration of vector. Previous studies indicated that activation of CD4+ T cells by virus capsid proteins is necessary for full realization of effector function of CD8+ T cells and B cells. In this paper, we present a strategy for preventing CD4+ T-cell activation by an adenovirus vector delivered to mouse liver and lung tissues which is based on interfering with T-cell priming via CD40 ligand-CD40 interactions. Adenovirus transgene expression was stabilized in mice genetically deficient in CD40 ligand (CD40L), and neutralizing antibody to adenovirus did not develop, allowing efficient readministration of vector. A transient blockade of T-cell activation with an antibody to CD40L infused into the animal at the time of adenovirus vector-mediated gene transfer led to stabilization of transgene expression and diminished production of neutralizing antibody, allowing readministration of vector. In vitro T-cell assays suggested that a block in the primary activation of CD4+ T cells was responsible for the lack of B-cell- and cytotoxic-T-cell-dependent responses. This suggests a strategy for improving the potential of adenovirus vectors based on administration of an antibody to CD40L at the time of vector administration.

Actins↗
PubMed1996

Differential changes in neurochemical markers of striatal dopamine nerve terminals in idiopathic Parkinson's disease.

To determine the extent that different dopamine (DA) neuronal markers provide similar estimates of striatal (caudate and putamen) DA nerve terminal loss in idiopathic Parkinson's disease (PD), we compared, in postmortem striatum of 12 patients with PD and 10 matched controls, levels of five different DA neuronal markers. These markers included DA itself, three different estimates of the density of the DA transporter (DAT) ([3H])GBR 12,935 and [3H]WIN 35,428 binding; DAT protein immunoreactivity), and one estimate of the vesicular monoamine transporter (VMAT2; [3H]DTBZ binding). Striatal levels of all examined DA markers in PD were significantly intercorrelated. However, the magnitude of loss relative to controls was unequal (DAT protein = DA > [3H]WIN 35,428 > [3H]DTBZ > [3H]GBR 12, 935), with the differences more marked in the severely affected putamen. The less severe reduction of binding of the DAT/VMAT2 radioligands relative to DA and DAT protein could be explained by differential regulation/degeneration of different DA nerve terminal components or lack of specificity of the radioligands for the DA neuron. These postmortem data may help in interpretation of in vivo neuroimaging studies in PD in which only one radioligand is routinely employed.

Aged↗
PubMed1996

Immune responses to viral antigens versus transgene product in the elimination of recombinant adenovirus-infected hepatocytes in vivo.

Human adenoviruses have been developed as an attractive vehicle for in vivo liver-directed gene therapy. Problems with the application of first generation recombinant adenoviruses to liver-directed gene therapy have been transient expression of the recombinant gene and development of hepatitis. Previous studies in mouse models of gene transfer to liver and lung suggested that MHC class I-restricted cytotoxic T lymphocytes (CTLs) to viral antigens may be effectors in the elimination of transgene expression. The goal of this study was to evaluate the importance of viral antigens versus transgene product in inducing CTL mediated hepatocyte destruction in vivo. Immunization of C57BL/6 mice with a lacZ-expressing adenovirus elicited CTL responses to both viral antigens and the transgene product, beta-galactosidase (beta-gal). Adoptive transfer experiments, as well as studies involving lacZ-transgenic mice (ROSA-26) revealed that CTLs to viral antigens are sufficient to destroy virus-infected hepatocytes, indicating that CTLs to beta-gal can not solely account for the observed hepatocyte destruction that has characterized the use of first generation viruses. In addition, we confirmed that B cell-mediated events do not participate in destruction of hepatocytes in vivo, despite the production of virus- and beta-gal-specific antibodies. These data confirm the hypothesis that viral gene expression elicits host responses that contribute to the problem of transgene instability. Recombinant adenoviruses must be redesigned to diminish viral gene expression if they are to be used in the treatment of chronic diseases.

Adenoviruses, Human↗
PubMed1996

Gradient of RGD-dependent entry of adenoviral vector in nasal and intrapulmonary epithelia: implications for gene therapy of cystic fibrosis.

The efficiency with which adenoviral vectors infect airway epithelial cells in vivo is unclear despite extensive preclinical and clinical studies. Our hypothesis is that gene transfer is limited by vector internalization which is mediated by binding of a fiber with a cellular receptor and the RGD motif of the penton base of the virus with cellular alpha v beta integrin. Experiments in mice demonstrate an anatomical gradient of susceptibility to adenoviral vector-mediated gene transfer with epithelia of proximal structures, such as nose and trachea, much less infectable than the distal noncartilaginous airway. Throughout the airway, gene transfer is dependent on RGD-mediated interactions which are rate limiting in the distal lung. A panel of tissues from cystic fibrosis and non-cystic fibrosis patients was analyzed for expression of alpha v beta 5 integrin which is capable of mediating RGD-dependent uptake of vector. Luminal epithelial cells of the nose and trachea were void of alpha v beta 5 expression whereas abundant expression of this integrin was present in virtually all epithelial cells of distal conducting airway. These findings could explain difficulties we and others have had in correcting the functional deficit of cystic fibrosis nasal epithelia and suggest that gene transfer efficiency may be greater in distal human lung.

Adenoviruses, Human↗
PubMed1996

Pathophysiology of congenital diaphragmatic hernia.

The patient born with congenital diaphragmatic hernia (CDH) presents with a multitude of problems. The pulmonary hypoplasia associated with CDH results in an inadequate surface area for gas exchange, decreased cross sectional area of the pulmonary vascular tree, precocious muscularization of the pulmonary vessels, and probable surfactant deficiency. Elevated levels of circulating vasoactive mediators, as well as a heightened sensitivity to these mediators, further compounds the pulmonary hypertension associated with CDH. We have reviewed the pathophysiology of CDH, with specific reference to how this knowledge has affected clinical management.

Extracorporeal Membrane Oxygenation↗
PubMed1996

Neonatal cotton rats do not exhibit destructive immune responses to adenoviral vectors.

Recombinant adenoviruses are being considered for treatment of cystic fibrosis lung disease. The utility of this vector system in adult recipients is limited by the formation of destructive humoral and cellular immune responses to the vector and vector-infected cells. We hypothesized that the host immune responses could be avoided by administering the vector early in development when the immune system is naive. This was evaluated in the context of newborn and adult cotton rats administered E1-deleted recombinant adenoviral vectors into the trachea. The results with adult cotton rats were consistent with previous studies in that gene expression was extremely high in the conducting airway when evaluated 3 days after administration of the vector. However, expression diminished to undetectable levels within 2 weeks and was associated with substantial inflammation and formation of neutralizing antibodies. The level of expression achieved in newborn cotton rats was equally high with reporter gene expression detected in both the conducting airway and alveolar cells. The immune response in the newborn cotton rats was substantially blunted with diminished CD4+ T cell activation, based on in vitro studies, as well as essentially no formation of neutralizing antibody. This translated to a substantially improved outcome with transgene expression persisting for over 6 months. The window of optimal immune tolerance was within 3 days of birth. Vector was readministered into animals 8-10 weeks after they had received the neonatal challenge of the initial vector. This second delivery of vector was efficient, consistent with the low neutralizing antibody in these animals. However, the animals mounted a full T cell response which correlated with extinction of the transgene from the vector administered at birth, as well as that of the second vector. Neutralizing antibodies did eventually develop following the second vector administration. These studies indicate that immune responses can be avoided if gene therapy is administered early in development. However, this so-called "tolerance' is broken when the animal receives a second vector after the immune system matures.

Adenoviridae↗
PubMed1996

Unusual electrocardiographic presentation of right ventricular myocardial infarction.

Isolated right ventricular infarction is uncommon, but when it occurs its prompt recognition may alter therapy substantially. Electrocardiographic changes accompanying acute right ventricular infarction are variable and may be difficult to recognize. The case of a 40-year-old man who had right ventricular infarction with unusual electrocardiographic findings is presented. The clinical, hemodynamic, and electrocardiographic findings of right ventricular infarction are discussed.

Adult↗
PubMed1996

The effect of mechanical forces on in utero lung growth in congenital diaphragmatic hernia.

Lung development is a complex process of lung growth and maturation. Although lung maturation appears to be principally regulated by hormonal and biochemical factors, lung growth appears to depend more on physical factors such as lung liquid volume, fetal breathing movements, the size of the intrathoracic space, and the amniotic fluid volume. This article focuses on these physical factors. Specific emphasis is given to the normal mechanisms responsible for lung growth, as well as the consequences of disruption of these normal mechanisms.

Animals↗
PubMed1996

Long-term outlook for survivors of congenital diaphragmatic hernia.

CDH patients are critically ill but can expect excellent survival if other serious anomalies are not present; however, significant long-term morbidities exist in the survivors. The most notable of these are developmental delay, poor growth, gastroesophageal reflux disease, hearing loss, and musculoskeletal abnormalities. Patients require careful long-term follow-up for these problems, and caregivers must continue to critically evaluate their medical interventions in the neonatal period to try to minimize these morbidities.

Child, Preschool↗
PubMed1996

Complete correction of hyperbilirubinemia in the Gunn rat model of Crigler-Najjar syndrome type I following transient in vivo adenovirus-mediated expression of human bilirubin UDP-glucuronosyltransferase.

Recombinant adenoviral vectors are useful for the in vivo expression of genes in hepatocytes. Adenoviral vectors deleted in E1a, E1b, and E3b were constructed and used to study in vivo expression of the major human bilirubin UDP-glucuronosyltransferase isoform (HUG Br1) under the transcriptional control of the cytomegalovirus (CMV) immediate-early promoter-enhancer (H5.010CMV hugBr1). As a control, a recombinant adenoviral vector containing the beta-galactosidase reporter gene driven by the CMV promoter-enhancer was employed (H5. 010CMVlacZ). Recombinant virus was expanded following exposure to E1 transcomplementing (293) cells and concentrated to t titer of approximately 10(13) particles per milliliter. A rat model for Crigler-Najjar syndrome type I deficient in HUG Br1 (ie the Gunn rat) was injected with 5 X 10(9) plaque-forming units (p.f.u.) via the portal vein of either H5.010CMVhugBr1 or H5. 010CMVlacZ. Rats from each set were killed at 3 days, 11 days and 22 days after infusion. Liver total cellular DNA, RNA and protein were analyzed for the transgene and the transgene product at the specified times. Analysis of livers by Southern blot hybridization demonstrates sequence-specific hybridization to adenoviral vector DNA, and Northern blot hybridization demonstrates sequence-specific hybridization to transgene-derived RNA. DNA levels peak at approximately one copy number at 3 days and decline over 22 days. RNA and Western blot analyses demonstrate overexpression of message and protein at 3 days, declining over 22 days. In virto functional assay for bilirubin glucuronosyl-transferase activity demonstrates overexpression of bilirubin UDP-glucurosyltransferase function. In situ hybridization of frozen sections to detect expressed mRNA using beta-galactosidasederived 35S-labeled riboprobes demonstrates adenovirus-derived transgene expression in hepatocytes. Significant drops in serum bilirubin levels were noted following expression of HUG Br1 but not beta-galactosidase. The drop in serum bilirubin correlates with the appearance of bilirubin glucuronides in bile. In summary, recombinant adenoviral vectors were used to demonstrate in vivo complementation of the genetic defect in Gunn rat livers with the HUG Br1 cDNA leading to a resolution of hyperbilirubinemia lasting approximately 7 weeks. These studies suggest that delivery of the HUG Br1 cDNA might provide a reasonable therapeutic benefit for Crigler-Najjar syndrome type I patients, as safe and efficacious gene delivery systems are developed.

Adenoviridae↗
PubMed1996

Transient immune blockade prevents formation of neutralizing antibody to recombinant adenovirus and allows repeated gene transfer to mouse liver.

The hepatotropic properties of human adenoviruses have been used to develop vectors for in vivo liver-directed gene therapy. Current limitations for this vector system are the associated hepatitis that develops as a result of antigen-specific cellular immune responses and the difficulty in accomplishing repeated gene transfer. This study uses mouse models to define immune responses of the recipient animal that have previously been shown to prevent successful re-administration of virus and suggests approaches for preventing the development of these blocking immune responses. Our studies are most consistent with class II MHC-dependent activation ot T helper cells and B cells to capsid proteins of the input virus leading to the production of antiviral neutralizing antibody following a primary exposure to virus; this capsid-specific antibody appears to bind to virus and prevents entry in the context of a second administration of virus. Transient ablation of CD4 function at the time of virus administration prevents the formation of neutralizing antibody thereby allowing efficient gene transfer after at least two subsequent administrations of virus. Experiments in beta(2)m(-) mice and C57BL/6 mice treated with IL-12 suggested a more selective ablation of immune function based on inhibiting the activation of the T(H2) subset of T helper cells. From these studies on immune mechanisms it is hoped that viable strategies can be developed to overcome the problem of humoral immunity that occurs after the initial genetic therapy.

Adenoviridae↗
PubMed1995

Clearance of adenovirus-infected hepatocytes by MHC class I-restricted CD4+ CTLs in vivo.

E1-deleted recombinant adenoviruses have been developed for liver-directed gene therapy because efficient gene transfer to hepatocytes can be achieved in vivo. However, these viruses also express viral proteins in hepatocytes, leading to the development of destructive immune responses. Our previous studies indicated that MHC class I-restricted C D8+CTLs are major effectors in eliminating virus-infected cells, and CD4+ cells are also necessary in developing a fully competent CTL response by secretion of IFN-gamma, which sensitizes the virus-infected hepatocytes to CTLs through up-regulation of MHC class I expression. In this study, we have used adoptive transfer techniques in combination with mice deficient in immune functions to further define the role of CD4+ cells in the primary response to adenovirus-mediated gene transfer to the liver. Our studies indicate that CD4+ cells alone are capable of destroying virus-infected hepatocytes. Adoptive transfer experiments with beta 2m- mice along with in vitro CTL assays suggest that these CD4+ can act as CTL effectors, which are MHC class I-restricted. Depletion of these CD4+ effectors in vivo leads to prolongation of adenovirus-mediated transgene expression in hepatocytes. These results suggest that class I-restricted CD4+ CTLs contribute to elimination of adenovirus-transduced hepatocytes and extend our understanding of functional importance of CD4+ cells in viral pathogenesis.

Adenoviridae↗