An antisense of protein kinase C-zeta inhibits proliferation of human airway smooth muscle cells

We hypothesized that an atypical isoform of protein kinase (PK) C, PKC-zeta, is essential for proliferation of human airway smooth muscle (HASM) cells in primary culture. Recombinant replication-deficient E1-deleted adenoviruses (100 plaque-forming units [pfu]/cell) expressing the antisense of PKC-zeta and the wild-type PKC-zeta (Ad-CMV-PKC-zeta) were added to actively growing cells that were subsequently incubated for 48 h in platelet-derived growth factor (PDGF) 40 ng/mL or 10% fetal bovine serum (FBS). Expression of the antisense at a virus concentration of 100 pfu/cell produced a significant (n = 3, P<0.05) decrease in the mean manual cell count in the presence of PDGF to 37+/-5% relative to that in cells with no virus (100%), whereas in cells infected with virus containing no construct, this figure was 102+/-13%. The increase in cell number in response to FBS, however, was not affected by the presence of the antisense. Corresponding values for cells in 10% FBS were 100+/-22%, 85+/-22%, and 122+/-18%. Western blotting revealed decreased levels of PKC-zeta protein, but not PKC-alpha or PKC-epsilon protein, in cells infected with the antisense when compared with levels in control cells. Thus, in HASM cells, PKC-zeta is involved in proliferation in response to PDGF, but not in response to FBS, for which alternate signal transduction pathways independent of PKC-zeta must exist.

Selective Rep-Cap gene amplification as a mechanism for high-titer recombinant AAV production from stable cell lines

Gene transfer vectors based on adeno-associated virus mediate high-level, stable gene expression in a variety of postmitotic tissues; thus, there is interest in developing improved production systems. We previously described the generation of rAAV producer cell lines that, upon infection with adenovirus, yielded biologically active rAAV particles. In these studies we show that the adenovirus multiplicity of infection (m.o.i.) is a critical variable for efficient production of cell line-derived rAAV and can affect yields by over 200-fold. Moreover, a threshold level of adenovirus was found necessary for high-titer vector production. To define the possible factors responsible for adenovirus m.o.i. -dependent rAAV yields, we analyzed rep and cap expression as a function of adenovirus m.o.i. High-level AAV capsid protein synthesis was observed in rAAV producer cells at adenovirus m.o.i. > or =10. This prompted us to analyze the rep-cap copy number following adenovirus infection. We documented robust episomal DNA amplification (100-fold) of integrated rep-cap sequences. Interestingly, no amplification of rep-cap sequences was observed when the sequences (in plasmid form) were transfected into adenovirus-infected HeLa cells. These data suggest that adenovirus-dependent rep-cap gene amplification is a critical process responsible for efficient rAAV synthesis in stable cell lines.

Augmented insulinotropic action of arachidonic acid through the lipoxygenase pathway in the obese Zucker rat

OBJECTIVE

The metabolism of arachidonic acid (AA) has been shown to be altered in severe insulin resistance that is present in obese (fa/fa) Zucker rats. We examined the effects and mechanism of action of AA on basal and glucose-stimulated insulin secretion in pancreatic islets isolated from obese (fa/fa) Zucker rats and their homozygous lean (Fa/Fa) littermates.

RESEARCH METHODS AND PROCEDURES

Islets were isolated from 10- to 12-week-old rats and incubated for 45 minutes in glucose concentrations ranging from 3.3 to 16.7 mM with or without inhibitors of the cyclooxygenase or lipoxygenase pathways. Medium insulin concentrations were measured by radioimmunoassay, and islet production of the 12-lipoxygenase metabolite, 12-hydroxyeicosatetraenoic acid (12-HETE), was measured by enzyme immunoassay.

RESULTS

In islets from lean animals, AA stimulated insulin secretion at submaximally stimulatory glucose levels (<11.1 mM) but not at 16.7 mM glucose. In contrast, in islets derived from obese rats, AA potentiated insulin secretion at all glucose concentrations. AA-induced insulin secretion was augmented in islets from obese compared with lean rats at high concentrations of AA in the presence of 3.3 mM glucose. Furthermore, the inhibitor of 12-lipoxygenase, esculetin (0.5 microM), inhibited AA-stimulated insulin secretion in islets from obese but not lean rats. Finally, the islet production of the 12-HETE was markedly enhanced in islets from obese rats, both in response to 16.7 mM glucose and to AA.

DISCUSSION

The insulin secretory response to AA is augmented in islets from obese Zucker rats by a mechanism related to enhanced activity of the 12-lipoxygenase pathway. Therefore, augmented action of AA may be a mechanism underlying the adaptation of insulin secretion to the increased demand caused by insulin resistance in these animals.

An epithelial-derived factor inhibits contraction in canine perfused bronchial segments

We have previously reported, using a novel preparation of canine airway segments, that the sensitivity of acetylcholine was greater when applied to the adventitial (outside) surface than the epithelial (inside) surface. The present study investigated if this "barrier-effect" was partly the result of pharmacological modulation by the epithelium. As previously demonstrated, canine airway segments were less sensitive to inside than outside application of acetylcholine (pD(2) 3.0+/-0.4 and 4.5+/-0.4, respectively, P<0.001, n=5). The addition of donor bronchi significantly decreased the sensitivity of the airway segment to outside application of acetylcholine (pD(2) 4.3+/-0.2 and 3.6+/-0.2, respectively, P<0.002, n=4). Indomethacin (2.5 microM) treatment of both the donor bronchi and the airway segment and removal of donor epithelium abolished the rightward shift in the acetylcholine-response curves. In addition, inhibition of cyclooxygenase within the airway segments themselves, but not the donor bronchi, also inhibited the rightward shift in the curves. These results indicate that the donor epithelium is capable of pharmacologically modulating responses of the airway segment to outside applied acetylcholine by producing an epithelial-derived factor, which in turn causes the release of a downstream cyclooxygenase product from within the airway segment.

Rapid detection of BCR/ABL and PML/RARA using fluorescence in situ hybridization in cytospin preparations

Fluorescence in situ hybridization (FISH) is increasingly used as an adjunct to conventional cytogenetic analysis in the diagnosis of haematological malignancies and in monitoring minimal residual disease. FISH, however, is generally performed on slides prepared after short-term sample incubation and therefore, whilst faster than conventional cytogenetics, still requires a minimum of 2 days for a result to be obtained. A simplification of the FISH procedure is reported using uncultured cytospin preparations of bone marrow or peripheral blood for the rapid diagnosis of the BCR-ABL and PML-RARa gene rearrangements. It demonstrates that culturing has no effect on the ratio of normal to abnormal cells in the nondividing population. Data is presented from an analysis of 24 cases in whom unequivocal results were obtained in less than 12 h and in complete concordance with results obtained by conventional cytogenetics and/or interphase FISH.

Eradication of a resistant Pseudomonas aeruginosa strain after a cluster of infections in a hematology/oncology unit

OBJECTIVES

This report chronicles an outbreak of a multiply resistant strain of Pseudomonas aeruginosa and the measures required to contain this outbreak.

METHODS

Laboratory-based ward-liaison surveillance allowed the detection of a multiply resistant strain of P. aeruginosa infecting patients in our hematology/oncology unit. Sampling of the immediate environment was carried out. Pulsed field gel electrophoresis was used to compare the patients' organisms with those found in the environment. Extensive dismantling of the drainage system, repeated cleaning and disinfection, and a review of the departmental antibiotic policy were some of the infection control measures instigated.

RESULTS

During a period of 11 months, three patients in the hematology department and two patients in the oncology department were infected with multiply resistant P. aeruginosa. There were two cases of pneumonia, one of which was fatal, and two cases of neutropenic septicaemia. Pulsed field gel electrophoresis performed on the isolates showed that the isolates from geographically separate areas could be divided into two strains that were closely related but distinct. Two genotypically identical strains were also isolated from the plumbing systems in the areas of each ward where patients had been treated.

CONCLUSIONS

The potential for serious nosocomial infections with P. aeruginosa is well recognized. Eradication of the organism from the environment may require the co-ordinated efforts of clinicians, nurses, pharmacy and hospital engineers, working in collaboration with the hospital infection control team. To date, the same strains have not been isolated despite repeated surveillance over the past 18 months and therefore these measures have, in our opinion, successfully removed the potential for nosocomial infection with this resistant organism in our hospital.

Transfer of the feline erythropoietin gene to cats using a recombinant adeno-associated virus vector

Chronic renal failure and the associated erythropoietin-responsive anemia afflicts over 2 million domestic cats in the United States, resulting in morbidity that can affect the owner-pet relationship. Although treatment of cats with recombinant human erythropoietin (Epo) protein can be effective, response to the drug often dissipates over time, probably due to the development of antibodies reactive with the human protein. As an alternate approach to the treatment of this disease, we have developed a recombinant adeno-associated virus vector containing the feline erythropoietin gene (rAAV/feEpo). This vector, when administered intramuscularly to normal healthy cats, caused a dose-related increase in hematocrit over a 7-week period after injection. Thus, the rAAV/feEpo vector holds promise as a simple, safe and effective therapy for the anemia of chronic renal failure in domestic cats.

Recombinant adeno-associated virus-mediated correction of lysosomal storage within the central nervous system of the adult mucopolysaccharidosis type VII mouse

The central nervous system (CNS) is a predominant site of involvement in several lysosomal storage diseases (LSDs); and for many patients, these diseases are diagnosed only after the onset of symptoms related to the progressive accumulation of macromolecules within lysosomes. The mucopolysaccharidosis type VII (MPS VII) mice are deficient for the lysosomal enzyme beta-glucuronidase and, by early adulthood, develop a significant degree of glycosaminoglycan storage within neuronal, glial, and leptomeningeal cells. Using this animal model, we investigated whether gene transfer mediated by a recombinant adeno-associated virus (rAAV) vector is capable of reversing the progression of storage lesions within the CNS. Adult MPS VII mice received intracerebral injections of 4 X 10(7) infectious units of a rAAV vector carrying the murine beta-glucuronidase (gus-s(a)) cDNA under the transcriptional direction of the cytomegalovirus immediate-early promoter and enhancer. By 1 month after vector administration, transgene-derived beta-glucuronidase was present surrounding the injection site. Enzyme levels were between 50 and 240% of that found in wild-type mice. This level of beta-glucuronidase activity was sufficient to reduce the degree of lysosomal storage. Moreover, the reduction in storage was maintained for at least 3 months post-rAAV administration. These data demonstrate that rAAV vectors can transduce the diseased CNS of MPS VII mice and mediate levels of transgene expression necessary for a therapeutic response. Thus, rAAV vectors are potential tools in the treatment of the mucopolysaccharidoses and other lysosomal storage diseases.

The risks of total pancreatectomy and splenic islet autotransplantation

The intraportal site is the most common site for islet transplantation. Many other sites have been tried experimentally, including the spleen, which has successfully lead to insulin independence in a number of animal models. Nevertheless, there are no detailed reports of total pancreatectomy and splenic islet autotransplantation in humans. Five patients underwent total pancreatectomy and splenic islet autotransplantation for chronic pancreatitis. Four patients had a pylorus-preserving total pancreatectomy and one patient a duodenal-preserving pancreatectomy. In three cases islets were embolized into both the portal vein and spleen. Two patients received splenic islet transplants alone. Islets were transplanted by retrograde venous infusion via the short gastric veins (n = 3), splenic vein stump (n = 1), and the left gastroepiploic vein (n = 1). The total volumes of transplanted pancreatic digest in those receiving combined intraportal and splenic autografts (n = 3) were 15.8, 13.0, and 13.5 ml. The volumes in those receiving a splenic-alone autograft (n = 2) were 12.0 and 5 ml. The mean rise in portal pressure was 18 cm of water. Complications related to the splenic autograft included a wedge splenic infarct, an emergency splenectomy, and a portal vein thrombosis in one patient having a combined intraportal and splenic autograft. Two patients developed insulin independence. two patients were still insulin independent at 1-year follow-up, and all had normal HbA1c levels (mean 5.6, range 5.2-6.3). Splenic islet autotransplantation, after total pancreatectomy, does lead to insulin independence. However, in our experience the combined procedure has a high morbidity because of splenic infarction and venous thrombosis.

GM-CSF production from human airway smooth muscle cells is potentiated by human serum

Recent evidence suggests that airway smooth muscle cells (ASMC) actively participate in the airway inflammatory process in asthma. Interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) induce ASMC to release inflammatory mediators in vitro. ASMC mediator release in vivo, however, may be influenced by features of the allergic asthmatic phenotype. We determined whether; (1) allergic asthmatic serum (AAS) modulates ASMC mediator release in response to IL-1beta and TNF-alpha, and (2) IL-1beta/TNF-alpha prime ASMC to release mediators in response to AAS. IL-5 and GM-CSF were quantified by ELISA in culture supernatants of; (1) ASMC pre-incubated with either AAS, nonallergic non-asthmatic serum (NAS) or Monomed (a serum substitute) and subsequently stimulated with IL-1beta and TNF-alpha and (2) ASMC stimulated with IL-1beta/TNF-alpha and subsequently exposed to either AAS, NAS or Monomed. IL-1beta and TNF-alpha induced GM-CSF release in ASMC pre-incubated with AAS was not greater than that in ASMC pre-incubated with NAS or Monomed. IL-1beta and TNF-alpha, however, primed ASMC to release GM-CSF in response to human serum. GM-CSF production following IL-1beta/TNF-alpha and serum exposure (AAS or NAS) was significantly greater than that following IL-1beta/TNF-alpha and Monomed exposure or IL-1beta/TNF-alpha exposure only. Whilst the potentiating effects of human serum were not specific to allergic asthma, these findings suggest that the secretory capacity of ASMC may be up-regulated during exacerbations of asthma, where there is evidence of vascular leakage.

Human eosinophil-airway smooth muscle cell interactions

Eosinophils are present throughout the airway wall of asthmatics. The nature of the interaction between human airway smooth muscle cells (ASMC) and eosinophils was investigated in this study. We demonstrated, using light microscopy, that freshly isolated eosinophils from healthy donors rapidly attach to ASMC in vitro. Numbers of attached eosinophils were highest at 2 h, falling to 50% of maximum by 20 h. Eosinophil attachment at 2 h was reduced to 72% of control by anti-VCAM-1, and to 74% at 20 h by anti-ICAM-1. Pre-treatment of ASMC for 24h with TNF-alpha, 10 nM, significantly increased eosinophil adhesion to 149 and 157% of control after 2 and 20 h. These results provide evidence that eosinophil interactions with ASMC involve VCAM-1 and ICAM-1 and are modulated by TNF-alpha.

Vaccination of macaques against pathogenic simian immunodeficiency virus with Venezuelan equine encephalitis virus replicon particles

Vaccine vectors derived from Venezuelan equine encephalitis virus (VEE) that expressed simian immunodeficiency virus (SIV) immunogens were tested in rhesus macaques as part of the effort to design a safe and effective vaccine for human immunodeficiency virus. Immunization with VEE replicon particles induced both humoral and cellular immune responses. Four of four vaccinated animals were protected against disease for at least 16 months following intravenous challenge with a pathogenic SIV swarm, while two of four controls required euthanasia at 10 and 11 weeks. Vaccination reduced the mean peak viral load 100-fold. The plasma viral load was reduced to below the limit of detection (1,500 genome copies/ml) in one vaccinated animal between 6 and 16 weeks postchallenge and in another from week 6 through the last sampling time (40 weeks postchallenge). The extent of reduction in challenge virus replication was directly correlated with the strength of the immune response induced by the vectors, which suggests that vaccination was effective.

Gene transfer into the CNS using recombinant adeno-associated virus: analysis of vector DNA forms resulting in sustained expression

Recombinant adeno-associated virus (rAAV) vectors have shown significant promise as vehicles for in vivo gene transfer, particularly for transduction of organs composed primarily of non-dividing cells (i.e., muscle, CNS, and liver). However, the mechanistic basis for this desirable property remains unclear. To investigate the fate of rAAV genomes in mouse brain, we stereotactically injected an rAAV vector carrying the E. coli lacZ gene into the caudate of BALB/c mice and demonstrate efficient transduction of mouse brain cells that possess cellular morphology consistent with post-mitotic neurons. We observed a significant increase in beta-galactosidase expression from 5 to 56 days after injection that paralleled the disappearance of single-stranded DNA input genomes. Analysis of in vivo viral DNA forms over time out to 5 months after inoculation revealed that rAAV genomes associated with high molecular weight mouse chromosomal DNA by 14 days after injection and persisted for the length of this study. The pattern of Southern hybridization was consistent with random viral integration in predominantly head-to-tail concatameric arrays. Importantly, we also documented an additional DNA species that appears to be a monomeric episomal circular form based on nuclease sensitivity assays. These data are the first to document the existence of multiple vector DNA forms present within the adult murine brain following direct rAAV inoculation and therefore, provide insight into the molecular events that ultimately result in long-term rAAV mediated transgene expression.

Brief periods of hyperphagia cause renal injury in the obese Zucker rat

BACKGROUND

Female obese (fa/fa) Zucker rats are maximally hyperphagic from the beginning of access to solid food until 20 weeks of age and die primarily from renal failure. We documented that urinary albumin excretion (UAE) rises early in obese rats during this time of greatest hyperphagia. This study was conducted to examine if this early surge of hyperphagia is critical to the initiation of glomerular damage.

METHODS

Three groups of six-week-old rats were used: (a) obese females fed ad libitum (AL-obese), (b) obese females pair fed to lean controls until 21 weeks and then allowed to eat ad libitum until 57 weeks (PF. AL-obese), (c) lean (Fa/Fa) Zucker rats fed ad libitum (AL-lean). Cohorts of AL-obese and PF.AL-obese rats were allowed to continue to death or 57 weeks of age, and the rest were terminated at 21 weeks for renal histology.

RESULTS

At 21 weeks, neither PF.AL-obese nor AL-lean rats had elevated UAE or glomerular histopathology. In contrast, glomerular injury was severe in AL-obese rats. UAE increased by 10 and 29 weeks in AL- and PF.AL-obese rats, respectively. Plasma triglycerides increased prior to UAE in both PF. AL- and AL-obese rats.

CONCLUSIONS

In obese rats fed ad libitum, hyperphagia is followed within a few weeks by hypertriglyceridemia and then by glomerular injury regardless of when ad libitum feeding is initiated. These events do not occur in lean rats or in obese rats pair fed to lean rats. Protective effects of pair feeding did not extend into the period of ad libitum feeding for PF.AL-obese rats. Hyperphagia quickly initiates glomerular injury in obese female Zucker rats.

The simian immunodeficiency virus envelope glycoprotein contains two epitopes presented by the Mamu-A*01 class I molecule

Cytotoxic T lymphocyte (CTL) responses against the simian immunodeficiency virus (SIV) envelope and Gag proteins were monitored in a Mamu-A*01-positive rhesus macaque infected with SIVsmE660. Peripheral blood mononuclear cells (PBMC) cultured with synthetic peptides spanning the entire gp160 and Gag coding region recognized a total of three epitopes. One located in Gag was identified as the previously described Mamu-A*01-restricted p11cC-->M epitope (CTPYDINQM). The other two epitopes, designated p15m and p54m, were located in the gp160 envelope protein. Both were nine amino acids in length and were predicted to bind Mamu-A*01 because they contained proline and leucine residues at positions 3 and 9, respectively. Indeed, expression of this class I major histocompatibility complex molecule was required for target cell recognition by envelope-specific CD8(+) T cells directed against both epitopes. These Mamu-A*01-restricted epitopes in the SIV envelope will be useful for monitoring immune responses in vaccinated or infected animals.

The Saccharomyces cerevisiae ubiquitin-proteasome system

Our studies of the yeast ubiquitin-proteasome pathway have uncovered a number of general principles that govern substrate selectivity and proteolysis in this complex system. Much of the work has focused on the destruction of a yeast transcription factor, MAT alpha 2. The alpha 2 protein is polyubiquitinated and rapidly degraded in alpha-haploid cells. One pathway of proteolytic targeting, which depends on two distinct endoplasmic reticulum-localized ubiquitin-conjugating enzymes, recognizes the hydrophobic face of an amphipathic helix in alpha 2. Interestingly, degradation of alpha 2 is blocked in a/alpha-diploid cells by heterodimer formation between the alpha 2 and a1 homeodomain proteins. The data suggest that degradation signals may overlap protein-protein interaction surfaces, allowing a straightforward steric mechanism for regulated degradation. Analysis of alpha 2 degradation led to the identification of both 20S and 26S proteasome subunits, and several key features of proteasome assembly and active-site formation were subsequently uncovered. Finally, it has become clear that protein (poly) ubiquitination is highly dynamic in vivo, and our studies of yeast de-ubiquitinating enzymes illustrate how such enzymes can facilitate the proteolysis of diverse substrates.

The safety and usefulness of routine bronchoscopy before stem cell transplantation and during neutropenia

Fibreoptic bronchoscopy with bronchoalveolar lavage (BAL) is used for clinical investigation and research into pulmonary complications of stem cell transplantation. Adverse effects of BAL are common in neutropenic patients with lung disease; there are few data on its safety when used routinely in transplant recipients without lung impairment. We describe the complications and usefulness for infection surveillance of routine BAL pre-transplantation and during neutropenia. Thirty-three patients before autologous or allogeneic BMT or PBSCT (B1) and 24 during post-transplant neutropenia (B2) underwent BAL; patients with pulmonary disease were excluded. Subjects were monitored for adverse effects, and BAL fluid was examined for pathogens. Complications of B2 were compared with events seen in 35 neutropenic patients who did not undergo BAL (C). Eighteen percent B1 and 33% B2 subjects showed complications of BAL. Fever occurred in 12% B1 and 26% previously afebrile B2 subjects, compared to 11% of C (P = 0.3). Epistaxis occurred in one B2 subject and two C. Potentially pathogenic organisms were isolated from 18% B1 and 13% B2 BAL fluids; none caused later respiratory infection. Bronchoscopy and BAL pre- and post-transplant had acceptable safety for a research procedure, but were not clinically helpful for infection surveillance.

A fatal cytokine-induced systemic inflammatory response reveals a critical role for NK cells

The mechanism of cytokine-induced shock remains poorly understood. The combination of IL-2 and IL-12 has synergistic antitumor activity in vivo, yet has been associated with significant toxicity. We examined the effects of IL-2 plus IL-12 in a murine model and found that the daily, simultaneous administration of IL-2 and IL-12 resulted in shock and 100% mortality within 4 to 12 days depending on the strain employed. Mice treated with IL-2 plus IL-12 exhibited NK cell apoptosis, pulmonary edema, degenerative lesions of the gastrointestinal tract, and elevated serum levels of proinflammatory cytokines and acute phase reactants. The actions of TNF-alpha, IFN-gamma, macrophage-inflammatory protein-1alpha, IL-1, IL-1-converting enzyme, Fas, perforin, inducible nitric oxide synthase, and STAT1 did not contribute to the observed toxicity, nor did B or T cells. However, toxicity and death from treatment with IL-2 plus IL-12 could be completely abrogated by elimination of NK cells. These results suggest that the fatal systemic inflammatory response induced by this cytokine treatment is critically dependent upon NK cells, but does not appear to be mediated by the known effector molecules of this cellular compartment. These data may provide insight into the pathogenesis of cytokine-induced shock in humans.

Highly purified recombinant adeno-associated virus vectors are biologically active and free of detectable helper and wild-type viruses

Gene transfer vectors based on the replication-defective human parvovirus, adeno-associated virus type 2 (AAV-2), are viable candidates for in vivo and ex vivo human use. However, widespread testing of AAV vectors has been limited by difficulties in generating pure, high-titer vector stocks that are fully characterized. To address these issues, we have developed a single-step purification scheme using heparin affinity chromatography. Recovery from the crude lysate starting material exceeds 70%, and the end product rAAV vector is highly purified and appears to be free of adenovirus and cellular contaminates. Importantly, purified vectors retain predicted in vivo biologic activity. Concurrently, we have developed simple and rapid approaches for vector quantification using real-time PCR. These new methods, combined with the use of stable producer cell lines for rAAV production, make the commercial production of rAAV vectors for human use truly viable and pragmatic.

The ethylene gas signal transduction pathway: a molecular perspective

The gaseous hormone ethylene induces diverse effects in plants throughout their life cycle. Ethylene response is regulated at multiple levels, from hormone synthesis and perception to signal transduction and transcriptional regulation. As more genes in the ethylene response pathway are cloned and characterized, they illustrate the precision with which signaling can be controlled. Wounding, pathogenic attack, flooding, fruit ripening, development, senescence, and ethylene treatment itself induce ethylene production. Ethylene binding to receptors with homology to two-component regulators triggers a kinase cascade that is propagated through the CTR1 Raf-like kinase and other components to the nucleus. Activation of the EIN3 family of nuclear proteins leads to induction of the relevant ethylene-responsive genes via other transcription factors, eliciting a response appropriate to the original stimulus.

Production of recombinant adeno-associated virus vectors using a packaging cell line and a hybrid recombinant adenovirus

Recombinant adeno-associated virus (rAAV) vectors are under consideration for a wide variety of gene therapy applications. One of the limitations of the rAAV vector system has been the difficulty in producing the vector in sufficient quantity for adequate preclinical and clinical evaluation. A common method for vector production involves large-scale transient transfection of multiple plasmids into cultured cells. Because this approach might not be feasible for clinical scale manufacturing, we have sought approaches for rAAV vector production that avoid transient transfection procedures. In previously reported work, we generated an AAV packaging cell line that produces infectious rAAV when the vector genome is transfected into the cell line as plasmid DNA. We have now extended this approach by constructing a hybrid recombinant adenovirus (rAd) that contains a complete rAAV vector genome in the E1 region. This hybrid virus is used to deliver the rAAV genome to the packaging cell line (in the place of plasmid transfection). rAAV is produced when the packaging cell line is infected with the hybrid adenovirus and wild-type adenovirus. This method avoids the need for plasmid transfection and is adaptable to large-scale manufacturing processes.

Adeno-associated virus-mediated gene transfer to the brain: duration and modulation of expression

Adeno-associated virus (AAV) is a promising vector for central nervous system (CNS) gene transfer, but a number of issues must be addressed if AAV is to be used for widespread delivery throughout the CNS. Our aim was to test the effect of dose, route of delivery, and hydroxyurea treatment on brain expression of beta-galactosidase activity after cerebral inoculation with an rAAV-lacZ vector (rAAV-beta-gal). We also wished to test whether an immune response appeared against the vector and the transgene product. We found in BALB/c mice that beta-Gal expression increased during the first 2 months after inoculation, then decreased slightly by 4 months, and continued out to 6, 12, and 15 months in single animals. Cerebral injection produced localized beta-Gal expression that did not diffuse to other regions despite a fivefold increase in injection volume. Intraventricular injection resulted in negligible transduction. Antibodies to AAV capsid protein and beta-Gal appeared at low levels at 2 and 4 months, but correlated poorly with beta-Gal expression and did not prevent readministration of rAAV-beta-gal. Hydroxyurea treatment did not result in increased transduction in vivo. We conclude that our study confirms rAAV vectors as having considerable potential for CNS gene transfer; however, several important problems must be addressed if this vector system is to be used for long-term transduction of the entire brain. Sustained, regulatable expression will be needed if rAAV is to be used in the treatment of chronic CNS disease. The difficulty in delivering AAV to diverse regions of the brain is an important problem that must be overcome if these vectors are to be used for anything beyond localized transduction.

Pancreatic islet autotransplantation combined with total pancreatectomy for the treatment of chronic pancreatitis--the Leicester experience

Islet autotransplantation offers the potential for preventing the surgically induced diabetes that is an inevitable consequence of total pancreatectomy. This paper describes the first islet autotransplant programme in the United Kingdom and the first series in the world to use the spleen as a site for the islet graft. Over an 11 month period, 7 patients underwent total pancreatectomy for chronic pancreatitis combined with a simultaneous islet autotransplant. All 7 patients had normal glucose-tolerance levels and normal C-peptide levels pre-operatively. In 6 patients, islets were embolized into the liver via the portal vein (median transplanted volume=8.5 ml). In addition, 3 patients received islets into the splenic sinusoids via a short gastric vein (median transplanted volume=4 ml). One patient received islets into the spleen alone. One patient died of a stroke 4 weeks post transplantation. Two patients have achieved insulin independence, with a further two patients achieving "transient" insulin independence (<1 month). The remaining 2 patients, although requiring reduced insulin doses, have not achieved insulin-independence. However, all patients have C-peptide levels within the normal range. In trying to explain these findings, split proinsulin levels were measured and found to be elevated. High levels of split proinsulin cross react with the C-peptide assay and this would explain the falsely elevated C-peptide levels. Indeed insulin levels in these patients were all below the normal range. These findings would suggest that the use of C-peptide levels as the "gold standard" for monitoring islet autograft function, may require reappraisal.