Growth and Nutritional Outcomes in Children Post-Haematopoietic Stem Cell Transplant without Exposure to Total Body Irradiation.

AIMS: Poor growth in childhood cancer survivors who undergo haematopoietic stem cell transplant (HSCT) without exposure to radiation is reported anecdotally, although literature to support this is limited. The aims of this study were to assess the change in height standard deviation score (SDS) and the final adult height (FAH) in children who underwent chemotherapy-only conditioned HSCT and to identify predictors of poor growth. MATERIALS AND METHODS: We conducted a retrospective hospital medical record review (1984-2010) of children (1-10 years) who underwent chemotherapy-only conditioned HSCT, noting anthropology measurements at cancer diagnosis, HSCT, 10 years old and FAH. RESULTS: The median age at HSCT of the 53 patients was 4.5 years, 75% had a haematological malignancy and 25% a solid tumour. Half of the cohort underwent allogenic HSCT and most (89%) conditioned with busulphan. The mean change in height SDS from primary cancer diagnosis to FAH was -1.21 (±1.18 SD), equivalent to 7-8.5 cm loss, with a mean FAH of -0.91 SDS (±1.10 SD). The greatest height loss occurred between diagnosis and HSCT (-0.77 SDS, 95% confidence interval -1.42, -0.12, P = 0.01), with no catch-up growth seen by FAH. Patients with solid tumours had the greatest height loss. Overall body mass index SDS did not change significantly over time, or by cancer type. CONCLUSIONS: Chemotherapy-only conditioned HSCT during childhood can impact FAH, with the greatest height loss occurring prior to HSCT and no catch-up growth after treatment finishes. Children transplanted for a solid tumour malignancy seem to be more at risk, possibly due to intensive treatment regimens, both pre-transplant and during conditioning.

EBV-associated primary CNS lymphoma occurring after immunosuppression is a distinct immunobiological entity.

Primary central nervous system lymphoma (PCNSL) is confined to the brain, eyes, and cerebrospinal fluid without evidence of systemic spread. Rarely, PCNSL occurs in the context of immunosuppression (eg, posttransplant lymphoproliferative disorders or HIV [AIDS-related PCNSL]). These cases are poorly characterized, have dismal outcome, and are typically Epstein-Barr virus (EBV)-associated (ie, tissue-positive). We used targeted sequencing and digital multiplex gene expression to compare the genetic landscape and tumor microenvironment (TME) of 91 PCNSL tissues all with diffuse large B-cell lymphoma histology. Forty-seven were EBV tissue-negative: 45 EBV- HIV- PCNSL and 2 EBV- HIV+ PCNSL; and 44 were EBV tissue-positive: 23 EBV+ HIV+ PCNSL and 21 EBV+ HIV- PCNSL. As with prior studies, EBV- HIV- PCNSL had frequent MYD88, CD79B, and PIM1 mutations, and enrichment for the activated B-cell (ABC) cell-of-origin subtype. In contrast, these mutations were absent in all EBV tissue-positive cases and ABC frequency was low. Furthermore, copy number loss in HLA class I/II and antigen-presenting/processing genes were rarely observed, indicating retained antigen presentation. To counter this, EBV+ HIV- PCNSL had a tolerogenic TME with elevated macrophage and immune-checkpoint gene expression, whereas AIDS-related PCNSL had low CD4 gene counts. EBV-associated PCNSL in the immunosuppressed is immunobiologically distinct from EBV- HIV- PCNSL, and, despite expressing an immunogenic virus, retains the ability to present EBV antigens. Results provide a framework for targeted treatment.

Cellular discrimination using in vitro Raman micro spectroscopy: the role of the nucleolus.

Raman micro spectroscopy has attracted considerable attention over the last few years to explore its possible clinical applications as a non-invasive powerful label-free in vitro screening tool in cancer diagnosis and monitoring, subcellular analysis of biochemical processes, drug uptake, mode of action and mechanisms of interaction as well as toxicity of, for example, chemotherapeutic agents. However, in order to evaluate accurately the potential of Raman micro spectroscopy for such applications it is essential to optimise measurement and data processing protocols associated with subcellular analysis. To this end, in vitro differentiation of cell lines is a basic proof of concept for the potential of the technique, and although many studies have indicated successful differentiation based on Raman micro spectroscopy, it is important, as the measurement and processing techniques are improved, to establish the biochemical and subcellular basis of that discrimination. In this study, Raman micro spectroscopy is used to compare and differentiate normal and cancer cells from human lung origin, A549 adenocarcinoma cell line, Calu-1 epidermoid non-small-cell and BEAS-2B normal immortalized bronchial epithelium cell line. Spectra were taken from the three subcellular compartments, cytoplasm, nucleus and nucleolus and Principal Components Analysis was used to compare the spectral profiles between the cell lines and, coupled to Linear Discriminant Analysis, to explore the optimum sensitivity and specificity of discrimination. To support the analysis, Raman micro spectroscopy was coupled with Flow Cytometry, Confocal Laser Scanning Microscopy and Atomic Force Microscopy. While all subcellular regions can be employed to differentiate the normal and cancer cell lines, optimum discrimination sensitivity and specificity is achieved using the spectra from the nucleolar region alone. Notably, only the nucleolar spectral profiles differentiate the two cancer cell lines. The results point to the importance of the nucleolar regions in diagnostic applications of Raman microscopy as well as further applications in subcellular analysis of cytological processes.

Analyses of ionizing radiation effects in vitro in peripheral blood lymphocytes with Raman spectroscopy.

The use of Raman spectroscopy to measure the biochemical profile of healthy and diseased cells and tissues may be a potential solution to many diagnostic problems in the clinic. Although extensively used to identify changes in the biochemical profiles of cancerous cells and tissue, Raman spectroscopy has been used less often for analyzing changes to the cellular environment by external factors such as ionizing radiation. In tandem with this, the biological impact of low doses of ionizing radiation remains poorly understood. Extensive studies have been performed on the radiobiological effects associated with radiation doses above 0.1 Gy, and are well characterized, but recent studies on low-dose radiation exposure have revealed complex and highly variable responses. We report here the novel finding that demonstrate the capability of Raman spectroscopy to detect radiation-induced damage responses in isolated lymphocytes irradiated with doses of 0.05 and 0.5 Gy. Lymphocytes were isolated from peripheral blood in a cohort of volunteers, cultured ex vivo and then irradiated. Within 1 h after irradiation spectral effects were observed with Raman microspectroscopy and principal component analysis and linear discriminant analysis at both doses relative to the sham-irradiated control (0 Gy). Cellular DNA damage was confirmed using parallel γ-H2AX fluorescence measurements on the extracted lymphocytes per donor and per dose. DNA damage measurements exhibited interindividual variability among both donors and dose, which matched that seen in the spectral variability in the lymphocyte cohort. Further evidence of links between spectral features and DNA damage was also observed, which may potentially allow noninvasive insight into the DNA remodeling that occurs after exposure to ionizing radiation.

Spatial variation of the colonic microbiota in patients with ulcerative colitis and control volunteers.

OBJECTIVES: The relevance of spatial composition in the microbial changes associated with UC is unclear. We coupled luminal brush samples, mucosal biopsies and laser capture microdissection with deep sequencing of the gut microbiota to develop an integrated spatial assessment of the microbial community in controls and UC. DESIGN: A total of 98 samples were sequenced to a mean depth of 31,642 reads from nine individuals, four control volunteers undergoing routine colonoscopy and five patients undergoing surgical colectomy for medically-refractory UC. Samples were retrieved at four colorectal locations, incorporating the luminal microbiota, mucus gel layer and whole mucosal biopsies. RESULTS: Interpersonal variability accounted for approximately half of the total variance. Surprisingly, within individuals, asymmetric Eigenvector map analysis demonstrated differentiation between the luminal and mucus gel microbiota, in both controls and UC, with no differentiation between colorectal regions. At a taxonomic level, differentiation was evident between both cohorts, as well as between the luminal and mucosal compartments, with a small group of taxa uniquely discriminating the luminal and mucosal microbiota in colitis. There was no correlation between regional inflammation and a breakdown in this spatial differentiation or bacterial diversity. CONCLUSIONS: Our study demonstrates a conserved spatial structure to the colonic microbiota, differentiating the luminal and mucosal communities, within the context of marked interpersonal variability. While elements of this structure overlap between UC and control volunteers, there are differences between the two groups, both in terms of the overall taxonomic composition and how spatial structure is ascribable to distinct taxa.

Correlations between colonic crypt mucin chemotype, inflammatory grade and Desulfovibrio species in ulcerative colitis.

AIM: The colonic mucus gel layer is composed of mucins that may be sulphated or sialyated. Sulphated mucins predominate in health while in ulcerative colitis (UC) sulphation is reduced. These differences result directly from inflammatory events. It may also be hypothesized that they arise in part from alterations in the colonic microbiota, particularly changes in the burden of sulphated mucin-metabolizing species, such as Desulfovibrio (DSV) bacteria. The aim of this study was to correlate colonic mucin chemotypes and inflammatory scores in health and UC and relate these changes to changes in the colonization of colonic crypts by DSV. METHOD: Paired colonic biopsies from 34 healthy controls (HC) and 19 patients with active UC were collected for the purpose of parallel histological and microbiological assessment. High-iron diamine and Alcian blue staining and haematoxylin and eosin of mucosal biopsy specimens were used to assess histological changes within the clinical spectrum of UC. Quantitative real-time polymerase chain reaction analysis was employed to determine the total and DSV copy number within the colonic crypts. RESULTS: Compared with HC, the mucin chemotype in UC was less sulphated and inversely correlated with the degree of mucosal inflammation. A weak but significant negative correlation was found between the abundance of sulphated mucins and DSV burden. CONCLUSION: Mucin composition strongly correlates with the degree of mucosal inflammation, and to a lesser extent with DSV burden. These data suggest that mucin chemotype and DSV burden are linked phenomena and highlight the need to consider changes in mucin chemotype in the setting of microbial dysbiosis occurring within the colitic colon. What does this paper add to the literature? Decreased sulphation of mucins has been associated with inflammation in ulcerative colitis. Currently there are few data describing the relationship between microbial species and changes in mucin chemotype. This study validates previous findings and presents evidence of changes in mucin chemotype occurring in tandem with coherent changes in the microbiota within crypt niches.

ADAM-17: a novel therapeutic target for triple negative breast cancer.

BACKGROUND: Validated targeted therapy is currently unavailable for patients with invasive breast cancer negative for oestrogen receptors, progesterone receptors and HER2 [i.e., those with triple-negative (TN) disease]. ADAM-17 is a protease involved in the activations of several ligands that bind to and promotes intracellular signalling from the EGFR/HER family of receptors. PATIENTS AND METHODS: Expression of ADAM-17 was measured in 86 triple-negative and 96 non-triple-negative breast cancers. The ADAM-17 specific inhibitor, PF-5480090 (TMI-002, Pfizer) was tested in a panel of breast cancer cell lines for effects on functional outputs. RESULTS: In this study we show using both Western blotting and immunohistochemistry that ADAM-17 is expressed at significantly higher levels in TN than non-TN breast cancers. Using a panel of breast cancer cell lines in culture, PF-5480090 was found to decrease release of the EGFR ligand, TGF-alpha, decrease levels of phosphorylated EGFR and block cell proliferation in a cell-type-dependent manner. Potentially important was the finding of a significant and moderately strong correlation between ADAM-17 activity and extent of proliferation inhibition by PF-5480090 (r = 0.809; p = 0.003; n = 11). Pretreatment of cell lines with PF-5480090 enhanced response to several different cytotoxic and anti-EGFR/HER agents. CONCLUSION: It is concluded that inhibition of ADAM-17, especially in combination with chemotherapy or anti-EGFR/HER inhibitors, may be a new approach for treating breast cancer, including patients with TN disease.

Compliance with school F-milk and non-F milk intake in 3 to 4 and 6 to 7-year-old children.

BACKGROUND: Fluoridated (F) milk schemes are employed in six countries to reduce dental caries in children. To maximise their benefits considerable uptake is required. Measuring compliance and understanding contributing factors is important in evaluating the effectiveness of schemes since it can be unclear whether reported sub-optimal fluoride (F) intakes, measured through urinary F excretion, are due to sub-optimal F contents of milks or lack of compliance with consumption. OBJECTIVES: To determine compliance with milk consumption for children receiving non-F or F milk (containing 0.5 or 0.9 mgF per 189 ml carton) and rationalise the use of compliance data for clinical observational or intervention studies involving F milk schemes. RESEARCH DESIGN: Partially randomised, partial cross-over study. PARTICIPANTS: 50 children aged 3-4 and 6-7y consuming non-F (n=50) and F milk (0.5 mgF; n=15 children; 0.9mg F; n=16 children) at school. RESULTS: Mean compliance for both non-F and F milk was > or =90% in each of the groups studied and showed no statistically significant difference for children using both milks. The 95% central range of proportions of milk consumed for groups of individuals was wider for 0.9mgF milk (25% to 100%) than for 0.5 mgF milk (81% to 100%) although the greatest range of variation in compliance for within individual observations was seen for non-F milk consumption and in older children. CONCLUSION: Assessment of compliance with consumption should be included when dental efficacy of F milk consumption is being investigated or evaluated to quantify F exposure from milk. This is important, particularly if a change in the F dose of F milk might be under consideration.

Developing an assessment in dental public health for clinical undergraduates attending a primary dental care outreach programme.

BACKGROUND: This paper describes the development and implementation of a Dental Public Health (DPH) assessment within the Primary Dental Care Outreach (PDCO) course at Newcastle University. The assessment was piloted alongside the delivery of the Bachelor of Dental Surgery (BDS) curriculum in accordance with established learning outcomes. AIM: To design and implement a pilot summative assessment, incorporating patients' social histories obtained by undergraduate students attending primary dental care outreach clinics. METHOD: Undergraduates were tasked with obtaining a detailed social history from a patient seen during their two-year outreach attachment. Each student submitted a written account of their patient's social history and placed this in context by researching a number of demographic and social variables centred upon their patient's home residence. The final component involved writing a concise case feature for a nominated newspaper based upon the case history, where students were encouraged to identify one or more public health messages using language appropriate to a lay readership. RESULTS: Seventy one clinical undergraduates (98.6% of the year-group) subsequently submitted all components of the assessment. Eighty six per cent of the year-group was deemed to have passed the assessment with 9.9% achieving a 'Merit' grade and 76% a 'Satisfactory' grade. Following the assessment, students and clinical teachers were asked for their feedback through a focus group for staff, and a brief feedback form for students. CONCLUSION: Undergraduates subsequently reported greater awareness of the significance and importance of obtaining a detailed social history and its relevance when devising appropriate and realistic treatment plans.

The development of a primary dental care outreach course.

The aim of this work was to develop the first north-east based primary dental care outreach (PDCO) course for clinical dental undergraduate students at Newcastle University. The process of course design will be described and involved review of the existing Bachelor of Dental Surgery (BDS) degree course in relation to previously published learning outcomes. Areas were identified where the existing BDS course did not meet fully these outcomes. This was followed by setting the PDCO course aims and objectives, intended learning outcomes, curriculum and structure. The educational strategy and methods of teaching and learning were subsequently developed together with a strategy for overall quality control of the teaching and learning experience. The newly developed curriculum was aligned with appropriate student assessment methods, including summative, formative and ipsative elements.

Decrease in numbers of glandular cell groups in post-LLETZ liquid-based cytology preparations.

OBJECTIVE: Large loop excision of the transformation zone (LLETZ) has become standard of care in the management of cervical squamous neoplasia and with cone biopsy glandular intraepithelial neoplasia. Controversy remains about the long-term effects of this traumatic procedure. The aim of this study was to count and compare the number of endocervical glandular cell groups in pre- and post-LLETZ cervical preparations using liquid-based cytology to establish a cyto-morphological correlate of destruction of the transformation zone. METHODS: The cytology/histology correlation audit records of the Cytopathology Department of St Luke's Hospital in 2003 and early 2004 were used to select patients with a cytological diagnosis of high grade dyskaryosis followed by LLETZ. Only those cases with post-LLETZ cytological follow-up were selected. Cases using conventional smears were excluded. One hundred and twenty slides (60 pairs of slides) in total were retrieved. The cases underwent review and all groups of >3 glandular cells in each slide were counted by AM while blinded as to whether smears were pre- or post-LLETZ. Medians were compared using a Mann-Whitney U-test. RESULTS: The median number of groups of endocervical glandular cells of the pre-treatment group was 5.5 and of the post-treatment group was 2.0. There were significantly fewer endocervical glandular cell groups in the post-LLETZ population (P = 0.03). CONCLUSIONS: The number of endocervical glandular groups in cervical cytological preparations decreases significantly following LLETZ procedure. This suggests that cytological follow-up may not be as useful in glandular neoplasia cases. Few or absent glandular cell groups in post-LLETZ preparations may have implications for adequacy assessment.

Adenovirus-mediated delivery of catalase to retinal pigment epithelial cells protects neighboring photoreceptors from photo-oxidative stress.

Oxidative stress is involved in the pathogenesis of many diseases. Overexpression of antioxidant enzymes by gene therapy may protect tissues from oxidative damage. Because the reactive oxygen species hydrogen peroxide can diffuse across cell membranes, we hypothesized that overexpression of the antioxidant catalase within certain cells might protect neighboring cells. To test this hypothesis, we transduced retinal pigment epithelial (RPE) cells in vitro and in vivo with adenovirus carrying the catalase gene (Ad.CMV.catalase). After transduction of only a subset of RPE cells in vitro, all cells in the culture were protected from exogenous hydrogen peroxide. Similarly, in vivo, eyes injected with Ad. CMV. catalase had high catalase levels in the RPE, which protected the adjacent photoreceptors from light damage and reduced photoreceptor oxidative stress as measured by the markers 4-hydroxynonenal and nitrotyrosine. Both in vitro and in vivo, gene therapy with Ad. CMV. catalase protected neighboring cells from oxidative stress-induced terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) positivity. The data provide a paradigm for antioxidant gene therapy with catalase, designed to protect not only transduced cells, but also neighboring cells.

Oral health and related factors in cystic fibrosis and other chronic respiratory disorders.

AIM: To compare the prevalence of dental caries, dental calculus, and enamel defects in children with cystic fibrosis (CF) and children with other chronic respiratory disorders. METHODS: A cross sectional observational survey. One examiner (AN) undertook oral examinations to assess dental caries, periodontal health, and enamel defects in children attending respiratory outpatient clinics. RESULTS: A total of 74 patients with CF (35 male; mean age 10.7 years, range 2.5-16.5) were compared with a control group of 106 patients with other chronic respiratory disorders (52 male; mean age 9.1 years, range 3.0-16.5). There were significantly more defects of enamel in the permanent teeth of CF patients, compared with the teeth of those children with other chronic respiratory disorders. In addition, non-significant trends towards a lower caries prevalence in both dentitions, increased numbers of sextants with calculus deposits, and a reduced number of healthy gingival sextants were observed in the patients with cystic fibrosis. CONCLUSIONS: Enamel defects, particularly enamel opacities, which can be disfiguring, are more common in CF patients. Early, regular dental visits may prevent such defects becoming dentally disabling and would also permit the removal of dental calculus deposits. The use of long term antibiotics and pancreatic enzymes may confer some protection against the development and progression of dental caries in patients with cystic fibrosis. The inclusion of a specialist paediatric dentist, as part of the multiprofessional team managing the care of these children, would be an advantage.

Efficient trans-splicing in the retina expands the utility of adeno-associated virus as a vector for gene therapy.

Recombinant vectors based on adeno-associated virus (AAV) can efficiently transduce many different cell types, including cells of the retina, resulting in stable gene expression. A major shortcoming of this vector is its small packaging capacity. A trans-splicing approach, which reconstitutes gene expression from two independent AAV vectors, can be used to overcome the vector's packaging limitations. The efficiency of this system to date has been disappointing, and therefore its utility for therapeutic application limited. We demonstrate here that efficiency and cellular specificity of trans-splicing is dependent on selection of the appropriate AAV serotype. Efficiency of transgene expression resulting from trans-splicing in skeletal muscle approaches that obtained when delivering the intact transgene when using AAV2 vectors packaged with AAV5 capsids (AAV2/5). This expands the potential of AAV vectors for retinal gene therapy. The use of AAV2/5 also increases the efficiency of trans-splicing in photoreceptors. Selection of the appropriate AAV serotype is likely to affect efficiency of trans-splicing in other organ systems as well.

Structure-activity relationship of indomethacin analogues for MRP-1, COX-1 and COX-2 inhibition. identification of novel chemotherapeutic drug resistance modulators.

We report the screening of analogues of indomethacin to investigate the structure-activity relationship (SAR) of indomethacin-mediated multidrug resistance associated protein-1 (MRP-1) inhibition. By examining the activities of compounds with minor variations of the parent structure, we were able to separate MRP-1, glutathione-S-transferase (GST), cyclooxygenase (COX)-1 and COX-2 inhibitory activities. Combination cytotoxicity assays were utilised to identify agents which possess synergistic potential in MRP-1-expressing cell lines. MRP-1 Inside Out Vesicles (IOVs) were utilised to demonstrate the ability of the indomethacin analogues to inhibit the pump directly. Most of the indomethacin analogues active as MRP-1 inhibitors were poor GST inhibitors when compared with the GST-inhibitory activity of indomethacin. Two of the MRP-1 inhibitory analogues were found to have no COX-1 inhibitory activity and low COX-2 inhibitory activity, suggesting potentially reduced clinical toxicity. One MRP-1 inhibitory indomethacin analogue was also found to have low COX-1 inhibitory activity, but significant COX-2 inhibitory activity, making this analogue again interesting in terms of low potential toxicity, but with the possibility of direct inhibitory effects on tumour growth.

Comparison of external jugular and central venous pressures in mechanically ventilated patient.

We compared central venous pressures, measured via a 150 mm triple lumen catheter in the internal jugular vein with simultaneous external jugular venous pressures, measured with a 5 mm cannula in the external jugular vein, in 24 patients undergoing major surgery. Patients were mechanically ventilated in the supine position. Six sets of paired measurements of mean central venous pressure and mean external jugular venous pressure were taken by a blinded observer, in random order and at end-expiration at 30-min intervals during surgery. Four patients were not studied because of a failure to cannulate the external jugular vein. The remaining 20 patients yielded 111 sets of paired measurements. The mean difference between external jugular venous pressure and central venous pressure was 0.3 mmHg over a range of central venous pressure of 0-22 mmHg. Limits of agreement were 3.6 to +3.0 mmHg (95% CI 4.1 to +3.5 mmHg). We conclude that external jugular venous pressure is an accurate estimate of central venous pressure in surgical patients undergoing mechanical ventilation.

Allogeneic bone marrow transplant improves outcome for juvenile myelomonocytic leukaemia.

OBJECTIVE: To correlate clinical presentation and therapeutic outcomes in children with a diagnosis of juvenile myelomonocytic leukaemia. METHODS: The medical records of 14 children who fulfilled the International Juvenile Myelomonocytic Leukaemia Working Group Criteria for a diagnosis of juvenile myelomonocytic leukaemia (JMML) presenting to a single institution were reviewed, and their clinical status at September 2000 was documented. RESULTS: The most common presenting features were hepatosplenomegaly and lymphadenopathy. Fifty per cent of cases presented in the first year of life. Nine of 14 patients initially received chemotherapy otherwise used in the treatment of acute myeloid or lymphoblastic leukaemia with no apparent benefit. All six patients who received conditioning therapy with chemotherapy alone, followed by allogeneic bone marrow transplant (BMT), are in complete remission at a median follow-up duration of 12 months (range 5-91 months). Five of six patients surviving post-allogeneic BMT received marrow from an unrelated donor. Only one of seven patients who did not receive BMT survived long-term. CONCLUSION: Children with a diagnosis of JMML should be treated with allogeneic BMT as soon as a suitable donor is found. The role of anti-leukaemic therapy in this disease, prior to BMT, requires further investigation in the context of a multicentre clinical trial.

Exchange of surface proteins impacts on viral vector cellular specificity and transduction characteristics: the retina as a model.

Recombinant vectors based on adeno-associated virus (AAV) or human immunodeficiency 1 (lentivirus) are promising tools for long term in vivo gene delivery. Their design allows the exchange of capsids or envelopes, respectively, theoretically providing the opportunity to transduce a range of cell types. We constructed AAV vectors encoding enhanced green fluorescent protein (EGFP) within an AAV serotype 2 (AAV2) genome contained in an AAV2, five or one capsid (called AAV2/2, AAV2/5 and AAV2/1, respectively). Similarly we produced lentiviral vectors, encoding the same expression cassette present in the AAV vectors, pseudotyped with proteins from vesicular stomatitis virus glycoprotein (VSVG) or Mokola envelopes. Transduction characteristics of these vectors were evaluated in the murine retina following subretinal or intravitreal administration. The time of onset of transgene expression and the targeted cell types differed between the various recombinants. Onset of transgene expression was 3-4 days for lentiviral vectors and AAV2/1. In contrast, onset was at 2-4 weeks for AAV2/5 and AAV2/2, respectively. After subretinal injection, both lenti-VSVG and AAV2/5 transduced the retinal pigment epithelium (RPE) and photoreceptors efficiently whereas transgene expression was restricted to RPE cells using lenti with the Mokola envelope or AAV2/1. After intravitreal administration, only AAV2/2 and lenti-VSVG transduced the inner retina. Vector-mediated fluorescence was detected in the retina for over 12 weeks for all of the vectors. We conclude that pseudotyping provides a useful means to manipulate viral vector cell targeting specificity as well as retinal transduction characteristics of vectors containing the same genome.