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J M Wilson

Publications and source records attributed to J M Wilson.

At least 307 records · Page 17Linked to original sources
PubMed1994

Adenovirus-mediated gene transfer of soluble vascular cell adhesion molecule to porcine interposition vein grafts.

BACKGROUND: The efficacy of aorto-coronary vein grafting is limited by early graft thrombosis and accelerated graft atherosclerosis. Direct adenovirus-mediated transfer of genes encoding inhibitory proteins may prevent or slow progression of vein graft disease. METHODS AND RESULTS: Recombinant adenoviruses containing the cDNA for the marker gene lacZ (Ad.CMVlacZ) or soluble vascular cell adhesion molecule (sVCAM) (Ad.CB-sVCAM) were used to infect segments of porcine jugular vein or human saphenous vein. Ex vivo testing showed expression of the introduced genes after incubation with Ad.CMVlacZ or Ad.CBsVCAM for periods from 1 to 24 hours, with an increase in transfection efficiency with increasing incubation time. Porcine jugular veins were then interposed as vascular grafts in the carotid arteries of four juvenile farm pigs after ex vivo gene transfer by incubation for 90 to 120 minutes with Ad.CMVlacZ or Ad.CBsVCAM. sVCAM-transfected carotid vein grafts were placed on one side and lacZ transfected veins were placed contralaterally as controls. Three days later, the vein graft segments were resected. Expression of the lacZ gene was confirmed by X-Gal chromagen staining and visualization by light and transmission electron microscopy. Gene expression was apparent in all layers of the vein graft wall, with prominent staining in the adventitia. sVCAM expression was confirmed by immunohistochemistry and in situ hybridization. CONCLUSIONS: We conclude that ex vivo gene transfer before vein grafting is feasible using a replication-deficient recombinant adenovirus and results in a high level of gene expression in vivo. The potential for this approach to prevent early vein graft thrombosis or accelerated vein graft atherosclerosis requires further evaluation.

Adenoviridae↗
PubMed1994

Ultrastructural localization of variant forms of cystic fibrosis transmembrane conductance regulator in human bronchial epithelial of xenografts.

Cystic fibrosis (CF) is caused by mutations in the gene encoding a cyclic adenosine monophosphate (cAMP)-regulated chloride (CI) channel called the CF transmembrane conductance regulator (CFTR). Previous in vitro studies have indicated that the most common mutation, delta F508 CFTR (a deletion of phenylalanine 508), encodes a protein that is trapped in the endoplasmic reticulum (ER), leading to loss of cAMP-regulated CI transport at the plasma membrane. Another common variant, G551D CFTR (a G-->D missense mutation at position 551), is properly transported to the plasma membrane but is unresponsive to cAMP. These hypotheses are based primarily on studies in culture cells. We have attempted to extend the in vitro experiments by characterizing the molecular pathogenesis of the common mutations, delta F508 and G551D, in the context of a more relevant setting, the pseudostratified epithelium of a proximal human airway. Recombinant adenoviruses were used to transduce normal and variant forms of CFTR into surface epithelial cells of human bronchial xenografts grown in nu/nu mice. Recombinant forms of CFTR RNA and protein were expressed at levels that exceed expression of the endogenous gene. Immunolocalization of CFTR at the light and electron microscopic level indicated that products of the wild type and G551D alleles are found primarily at the apical plasma membrane of ciliated cells, while the delta F508 variant is distributed diffusely throughout the ER. Our data support previous observations primarily made in vitro that the G551D variant is a dysfunctional channel that is properly processed and that the delta F508 variant undergoes biosynthetic arrest at the level of the ER.

Adenoviridae↗
PubMed1994

Expression of the cystic fibrosis gene in adult human lung.

Critical to an understanding of the pulmonary disease in cystic fibrosis (CF) and the development of effective gene therapies is a definition of the distribution and regulation of CF gene expression in adult human lung. Previous studies have detected the product of the CF gene, the CF transmembrane conductance regulator (CFTR), in submucosal glands of human bronchi. In this report, we have characterized the distribution of CFTR RNA and protein in the distal airway and alveoli of human lungs. Samples from eight human lungs were analyzed for CFTR expression by in situ hybridization and immunocytochemistry. CFTR was detected in a subpopulation of epithelial cells at every level of the distal lung, including proximal, terminal, and respiratory bronchioles, and the alveoli. However, there was substantial variation in the level of CFTR expression between samples. In bronchioles, CFTR protein localized to the apical plasma membrane and was found primarily in a subpopulation of nonciliated cells. CFTR was expressed in the same distribution as the Clara cell marker CC10 in proximal bronchioles, however, expression was discordant in the more distal bronchioles and alveoli where CC10 was not detected. These studies suggest that epithelial cells of the distal lung may play a primary role in the pathogenesis of CF as well as expand the spectrum of target cells that should be considered in the development of gene therapies.

Adult↗
PubMed1994

Efficient catheter-mediated gene transfer into the heart using replication-defective adenovirus.

The ability to express recombinant genes in the coronary vasculature and the myocardium holds promise for the treatment of a number of acquired and inherited cardiovascular diseases. Previous in vivo gene transfer approaches in the heart have been limited by relatively low efficiencies of gene transduction. In this report, we demonstrate that catheter-mediated infusion of replication-defective adenovirus into the coronary arterial circulation in vivo represents a novel and efficient method for the induction of recombinant gene expression in both the coronary arteries and the myocardium. A single intracoronary infusion of 2 x 10(9) - 1 x 10(10) p.f.u. of adenovirus resulted in high level recombinant gene expression in both the coronary arteries and surrounding myocardium of adult rabbits for at least 2 weeks. No inflammatory response or myocardial necrosis was observed following the adenovirus infusions. The polymerase chain reaction (PCR) was used to assess the tissue distribution of infection following intracoronary infusion of adenovirus. Adenovirus DNA was detected by PCR in the livers, kidneys, lungs, brains and testes of animals 5 days after virus infusion. Percutaneous transluminal gene transfer (PTGT) into the heart by intracoronary infusion of replication-defective adenovirus represents a relatively non-invasive and efficient method of inducing recombinant gene expression both in the coronary arterial wall and in the surrounding myocardium.

Adenoviridae↗
PubMed1994

Lung development.

Human lung development is divided into five stages: embryonic, pseudoglandular, canalicular, saccular, and alveolar. The boundaries between these stages are not sharp; rather, overlap occurs between various gestational ages and individuals. The anatomic and morphological characteristics of each stage are described; general principles of lung development and cytodifferentiation of type I and type II pneumocytes are discussed. The complex phenomenon of lung development incorporates two processes--lung growth and lung maturation. Although these processes are developmentally related, they appear to be separately controlled. Lung growth seems to be influenced primarily by physical factors such as intrathoracic space, lung liquid volume and pressure, and amniotic fluid volume among others. Special attention is given to fetal lung liquid dynamics and the effects of its manipulation on lung growth, particularly by tracheal occlusion. Lung maturation has two components--structural and biochemical (ie, surfactant). Structural lung maturation appears to be regulated by physical factors. Physical factors that produce hypoplasia produce structurally immature lungs, whereas physical factors that produce hyperplasia produce structurally mature lungs. Biochemical maturation appears to be hormonally regulated by several endocrine organs (pituitary, adrenal, thyroid) and a host of endocrine factors including corticotropin, cortisol, thyroid hormones, and others.

Animals↗
PubMed1994

Heterogeneous subregional binding patterns of 3H-WIN 35,428 and 3H-GBR 12,935 are differentially regulated by chronic cocaine self-administration.

We examined the influence of chronic cocaine exposure, in an unlimited access self-administration paradigm, on density of the dopamine transporter (3H-WIN 35,428 and 3H-GBR 12,935 binding) and concentration of monoamine (dopamine, serotonin, noradrenaline and metabolites) neurotransmitters in rat brain. In normal rodent striatum 3H-WIN 35,428 and 3H-GBR 12,935 binding to the dopamine transporter, although generally similar, showed different subregional rostrocaudal and mediolateral gradients, suggesting that the two ligands might bind to different subtypes or states of the dopamine transporter. Following chronic, unlimited access cocaine self-administration, binding of 3H-WIN 35,428 was significantly elevated in whole nucleus accumbens (+69%, p < 0.001) and striatum (+65%, p < 0.001) on the last day of cocaine exposure ("on-cocaine group"); whereas in the 3 week withdrawn animals ("cocaine-withdrawn group"), levels were either normal (striatum) or reduced (-30%, p < 0.05, nucleus accumbens). Although similar changes in 3H-GBR 12,935 binding were observed, this dopamine transporter ligand showed a smaller and highly subregionally dependent increase in binding in striatal subdivision of the on-cocaine group, but a more marked binding reduction in the cocaine-withdrawn animals. As compared with the controls, mean dopamine levels were reduced in striatum (-15%, p < 0.05) of the on-cocaine group and in nucleus accumbens (-40%, p < 0.05) of the cocaine-withdrawn group. These data provide additional support to the hypothesis that some of the long-term effects of cocaine exposure (drug craving, depression) could be consequent to reduced nucleus accumbens dopamine function. Our data also suggest that dopamine transporter concentration, and perhaps function, might undergo up- or downregulation, either as a direct effect of cocaine, or indirectly as part of a homeostatic response to altered synaptic dopamine levels, and therefore might participate in the neuronal events underlying cocaine-induced behavioral changes.

Animals↗
PubMed1994

Pharmacological heterogeneity of the cloned and native human dopamine transporter: disassociation of [3H]WIN 35,428 and [3H]GBR 12,935 binding.

Controversy exists as to whether the functional state of the dopamine (DA) transporter is identical to sites mediating the specific binding of selective DA transporter radioligands. Therefore, we compared the pharmacological profile of numerous dopamine transport substrates and inhibitors on [3H]DA uptake with the binding of [3H]WIN 35,428 and [3H]GBR 12,935 to COS-7 cells transiently expressing the cloned human DA transporter. [3H]DA uptake and [3H]WIN 35,428 binding was specific, saturable, and to a single class of binding sites with an estimated Km/Vmax of approximately 2 microM and 6 pmol/min/10(5) cells for DA uptake and Kd/Bmax values of approximately 10 nM and 113 fmol/10(5) cells for [3H]WIN 35,428. [3H]DA uptake was inhibited in a concentration-dependent and uniphasic manner by dopaminergic agents with an appropriate rank order of potency for the DA transporter. Although most uptake blockers inhibited [3H]WIN 35,428 binding in a uniphasic manner, WIN 35,428, Lu 19,005, D-amphetamine, and DA clearly displayed the presence of both high and low affinity components. Comparison of the Ki values for the inhibition of [3H]DA uptake with [3H]WIN 35,428 binding reveals that, for uptake blockers and D-amphetamine, it is the high affinity component that shares pharmacological identity with effects on DA uptake (r = 0.9985), whereas for DA it is the low affinity site. In striking contrast, however, [3H]GBR 12,935 binding to COS-7 cells could not be made to exhibit a pharmacological profile indicative of the DA transporter and suggests that the site regulating functional [3H]DA uptake may not be identical with sites labeled by [3H]GBR 12,935 in these cells. Moreover, these sites appear unrelated to those previously described in native membranes as "piperazine acceptor" or P450 proteins. Comparison of Ki values and rank order of potency for the inhibition of [3H]WIN 35,428 or [3H]GBR 12,935 binding to human caudate membranes reveals pharmacological homology, but not identity, with that of the cloned DA uptake process. Taken together, these data suggest that 1) [3H]WIN 35,428 recognizes two sites of the DA transporter, of which only one appears to represent the functional state of the protein, and 2) [3H]WIN 35,428 and [3H]GBR 12,935 do not appear to bind the same functional form/state of the DA transporter. Whether the nonidentity of binding sites is a manifestation of some post-translational regulatory event (e.g., phosphorylation/accessory binding protein) or caused by the existence of multiple molecular forms of the DA transporter is currently unknown.

Amino Acid Sequence↗
PubMed1993

The common variant of cystic fibrosis transmembrane conductance regulator is recognized by hsp70 and degraded in a pre-Golgi nonlysosomal compartment.

The most common cause of cystic fibrosis is deletion of Phe-508 (delta F508) from the cystic fibrosis transmembrane conductance regulator (CFTR). Previous studies have suggested that delta F508 CFTR is an unstable protein that retains a pattern of glycosylation specific to the endoplasmic reticulum. This report examines the mechanism responsible for the mislocalization of delta F508 CFTR in a human cystic fibrosis epithelial cell line overexpressing recombinant CFTR by virtue of adenovirus-mediated gene transfer. Immunoelectron microscopy confirmed that wild-type CFTR is delivered to the plasma membrane of these cells and that delta F508 CFTR is retained in the endoplasmic reticulum. Pulse-chase studies showed that newly synthesized CFTR complexes with the chaperone hsp70. The wild-type protein dissociates from hsp70 before its transport to the Golgi, and the protein is subsequently degraded in lysosomes. By contrast, the complex formed between delta F508 CFTR and hsp70 is retained in the endoplasmic reticulum and delta F508 CFTR is rapidly degraded in a pre-Golgi nonlysosomal compartment. Thus, hsp70 discriminates between the normal form of CFTR and the form of the protein that most commonly causes cystic fibrosis (delta F508). These findings clarify the mechanism by which mutation causing delta F508 affects the intracellular trafficking of CFTR and suggest another function for hsp70 in ensuring quality control during the biosynthesis of plasma-membrane proteins.

Biological Transport↗
PubMed1993

Therapeutic strategies for familial hypercholesterolemia based on somatic gene transfer.

Inherited dyslipidemias are important risk factors for the premature development of coronary artery disease. One example is an inherited deficiency of low density lipoprotein (LDL) receptors that leads to the syndrome familial hypercholesterolemia (FH). We have used FH as a model for developing new approaches for treating this group of disorders by somatic gene therapy. Experiments in animal models that led to the initiation of a clinical trial of homozygous FH will be presented in this review.

Animals↗
PubMed1993

An approach for treating the hepatobiliary disease of cystic fibrosis by somatic gene transfer.

Cystic fibrosis (CF) is an inherited disease of epithelial cell ion transport that is associated with pathology in multiple organ systems, including lung, pancreas, and liver. As treatment of the pulmonary manifestations of CF has improved, management of CF liver disease has become increasingly important in adult patients. This report describes an approach for treating CF liver disease by somatic gene transfer. In situ hybridization and immunocytochemistry analysis of rat liver sections indicated that the endogenous CFTR (cystic fibrosis transmembrane conductance regulator) gene is primarily expressed in the intrahepatic biliary epithelial cells. To specifically target recombinant genes to the biliary epithelium in vivo, recombinant adenoviruses expressing lacZ or human CFTR were infused retrograde into the biliary tract through the common bile duct. Conditions were established for achieving recombinant gene expression in virtually all cells of the intrahepatic bile ducts in vivo. Expression persisted in the smaller bile ducts for the duration of the experiment, which was 21 days. These studies suggest that it may be feasible to prevent CF liver disease by genetically reconstituting CFTR expression in the biliary tract, using an approach that is clinically feasible.

Adenoviridae↗
PubMed1993

Adenovirus-mediated correction of the genetic defect in hepatocytes from patients with familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is an inherited deficiency of LDL receptors that has been an important model for liver-directed gene therapy. We are developing approaches for treating FH that are based on direct delivery of recombinant LDL receptor genes to liver in vivo. As a first step towards this goal, replication-defective recombinant adenoviruses were constructed which contained either the lacZ gene or the human LDL receptor cDNA expressed from a beta-actin promoter. Primary cultures of hepatocytes were established from two patients with homozygous FH and one nonFH patient, and subsequently exposed to recombinant adenoviruses at MOIs ranging from 0.1 to 5. Essentially all of the cells expressed high levels of the transgene without demonstrable expression of an early or late adenoviral gene product; the level of recombinant-derived LDL receptor protein in transduced FH hepatocytes exceeded the endogenous levels by at least 20-fold. These studies support the utility of recombinant adenoviruses for efficient transduction of recombinant LDL receptor genes into human FH hepatocytes without expression of viral proteins.

Adenoviridae↗
PubMed1993

Intratracheal pulmonary ventilation and congenital diaphragmatic hernia: a report of two cases.

Previous studies from our institution have shown that neonates with congenital diaphragmatic hernia (CDH), whose best postductal PaO2 (BPDPO2) was less than 100 mm Hg while on maximal conventional mechanical ventilation (CMV), had a mortality exceeding 90%. When combined with extracorporeal membrane oxygenation (ECMO), the mortality rose to 100% in those infants who developed hypercarbia following decannulation. Historically, those patients have required increasing ventilator support, leading to iatrogenic lung damage, and eventual death. Intratracheal pulmonary ventilation (ITPV) using the reverse thrust catheter (RTC) developed by Kolobow incorporates a continuous flow of humidified gas through a reverse Venturi catheter positioned at the distal end of the endotracheal tube. In animal studies, ITPV was shown to result in a reduced physiological dead-space (VD), to facilitate expiration, and to enhance CO2 elimination. In our current study, we have applied ITPV in two neonates with CDH who could not be weaned from ECMO because of uncontrollable hypercapnia, and who met above criteria for 100% mortality. In both cases, ITPV restored normal PaCO2 at low peak inspiratory pressure (PIP) with a substantial decrease in VD. We believe ITPV is suited to ventilating newborns with CDH in whom barotrauma is known to be common. Beyond its present use, ITPV may be useful to ventilate children with other forms of respiratory failure, and should be so considered along with other now available methods of mechanical pulmonary ventilation.

Hernia, Diaphragmatic↗
PubMed1993

Experimental fetal tracheal ligation prevents the pulmonary hypoplasia associated with fetal nephrectomy: possible application for congenital diaphragmatic hernia.

Pulmonary hypoplasia has a definite clinical impact in a variety of congenital diseases such as renal dysplasia and congenital diaphragmatic hernia. These diseases have in common inadequate growth and development of fetal lungs. Previous reports have demonstrated increased lung growth with in utero tracheal ligation. The purpose of this study was to determine if lung growth can be accelerated in the setting of experimental pulmonary hypoplasia. Ninety-five-day gestation fetal sheep were divided into four experimental groups: nephrectomy, nephrectomy with tracheal ligation, tracheal ligation alone, and sham-operated control animals. Animals were delivered near term and their lungs inflation fixed at 25 cm H2O. Total alveolar number (Alv#), total alveolar surface area (AlvSA), and lung volume to body weight ratios (LV:BW) were determined for apical and basilar segments of each animal and then averaged. Total lung DNA and protein content were also analyzed. The nephrectomy group had smaller lungs than control animals with decreased Alv#, AlvSA, and LV:BW. In contrast, nephrectomy with tracheal ligation produced large lungs which had increased Alv#, AlvSA, and LV:BW when compared with both the nephrectomy and the control group (P < .01). Total lung DNA and protein concentrations were both markedly elevated in the tracheally obstructed groups. However, the DNA/protein ratios remained constant in all four groups, suggesting that lung growth had occurred through cell multiplication. Photomicrographs of the lung demonstrated a histologically immature appearance in the nephrectomy group and a histologically mature appearance in the tracheally obstructed groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Aminocaproic acid decreases the incidence of intracranial hemorrhage and other hemorrhagic complications of ECMO.

Since the inception of extracorporeal membrane oxygenation (ECMO), hemorrhage has been a major complication often limiting its usefulness. This study was undertaken to evaluate the effect of aminocaproic acid (AMICAR), an inhibitor of fibrinolysis, on all hemorrhagic complications of ECMO including intracranial hemorrhage (ICH). In 1990, 49 neonates and 5 older children received ECMO therapy. None of these patients received AMICAR. In 1991, 51 neonates and 5 older children received ECMO. Forty-two of these patients who were considered to be at high risk for bleeding complications (preexisting or anticipated surgical procedures, preexisting ICH, or profound hypoxia, acidosis, coagulopathy, or prematurity) were given AMICAR. The remaining 14 low-risk neonates did not receive AMICAR, and for purposes of analysis were combined with the 1990 group. AMICAR was administered just prior to or after cannulation (100 mg/kg, intravenously) and was infused continuously at 30 mg/kg/h until decannulation. Except for the addition of AMICAR, the ECMO protocol was identical for these two patient groups. Patients who received AMICAR had significantly less bleeding while on ECMO (P = .03) and required fewer blood transfusions (P = .01) than patients not receiving AMICAR. This difference was most significant in the congenital diaphragmatic hernia and cardiac subgroups (P = .0001) and was not significant in the meconium aspiration subgroup (P = .1). The incidence of ICH in the neonatal subgroup was also significantly reduced with no patient on AMICAR developing a new or extending a preexisting ICH (P = .007). Reexploration of the cannulation site for bleeding was also reduced in the AMICAR-treated group but the difference failed to reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminocaproates↗
PubMed1993

Intravenous versus subcutaneous dosing of epoetin: a review of the literature.

Recombinant human erythropoietin (epoetin) is approved to be administered by the intravenous (i.v.) or subcutaneous (SC) route. Several studies have been conducted and published that compare the relative pharmacokinetics and efficacy of the IV and SC routes. An analysis of the methodology and results of these studies reveals that the data have been somewhat contradictory and highly variable. However, most investigations have concluded that the SC route is associated with a decreased dose requirement in the correction and/or maintenance phase. To justify a switch from the i.v. to the SC route, it is important to consider the practical implications, including patient and staff acceptance, as well as the financial aspects. Regardless of the route of administration, dose titration must be individualized based on the patient's response to epoetin therapy, red blood cell turnover rate, and iron status. More studies are needed to develop a standardized cost-effective method for epoetin dosing in patients on dialysis.

Biological Availability↗