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2.  Randomized Trial of a Family-based, Automated, Conversational Obesity Treatment Program for Underserved Populations 
Obesity (Silver Spring, Md.)  2013;21(9):E369-E378.
To evaluate the acceptability and feasibility of a scalable obesity treatment program integrated with pediatric primary care and delivered using interactive voice technology (IVR) to families from underserved populations.
Design and Methods
Fifty parent-child dyads (child 9–12 yrs, BMI >95th percentile) were recruited from a pediatric primary care clinic and randomized to either an IVR or a wait-list control (WLC) group. The majority were lower-income, African-American (72%) families. Dyads received IVR calls for 12 weeks. Call content was informed by two evidenced-based interventions. Anthropometric and behavioral variables were assessed at baseline and 3 mo follow-up.
Forty-three dyads completed the study. IVR parents ate 1 cup more fruit than WLC (p < .05). No other groups differences were found. Children classified as high users of the IVR decreased weight, BMI and BMI z-score compared to low users (p<.05). Mean number of calls for parents and children were 9.1 (5.2 SD) and 9.0 (5.7 SD), respectively. Of those who made calls, >75% agreed that the calls were useful, made for people like them, credible, and helped them eat healthy foods.
An obesity treatment program delivered via IVR may be an acceptable and feasible resource for families from underserved populations.
PMCID: PMC3695059  PMID: 23512915
3.  Homozygous mutation of MTPAP causes cellular radiosensitivity and persistent DNA double-strand breaks 
Cell Death & Disease  2014;5(3):e1130-.
The study of rare human syndromes characterized by radiosensitivity has been instrumental in identifying novel proteins and pathways involved in DNA damage responses to ionizing radiation. In the present study, a mutation in mitochondrial poly-A-polymerase (MTPAP), not previously recognized for its role in the DNA damage response, was identified by exome sequencing and subsequently associated with cellular radiosensitivity. Cell lines derived from two patients with the homozygous MTPAP missense mutation were radiosensitive, and this radiosensitivity could be abrogated by transfection of wild-type mtPAP cDNA into mtPAP-deficient cell lines. Further analysis of the cellular phenotype revealed delayed DNA repair, increased levels of DNA double-strand breaks, increased reactive oxygen species (ROS), and increased cell death after irradiation (IR). Pre-IR treatment of cells with the potent anti-oxidants, α-lipoic acid and n-acetylcysteine, was sufficient to abrogate the DNA repair and clonogenic survival defects. Our results firmly establish that mutation of the MTPAP gene results in a cellular phenotype of increased DNA damage, reduced repair kinetics, increased cell death by apoptosis, and reduced clonogenic survival after exposure to ionizing radiation, suggesting a pathogenesis that involves the disruption of ROS homeostasis.
PMCID: PMC3973239  PMID: 24651433
radiosensitivity; MTPAP; DNA repair; sequencing; reactive oxygen species; DNA damage
4.  Influence of health insurance, hospital factors and physician volume on receipt of immediate post-mastectomy reconstruction in women with invasive and non-invasive breast cancer 
For women with breast cancer who undergo mastectomy, immediate breast reconstruction (IR) offers a cosmetic and psychological advantage. We evaluated the association between demographic, hospital, surgeon and insurance factors and receipt of IR. We conducted a retrospective hospital-based analysis with the Perspective database. Women who underwent a mastectomy for invasive breast cancer (IBC) and ductal carcinoma in situ (DCIS) from 2000 to 2010 were included. Logistic regression analysis was used to determine factors predictive of IR. Analyses were stratified by age (<50 vs. ≥50) and IBC versus DCIS. Of the 108,992 women with IBC who underwent mastectomy, 30,859 (28.3 %) underwent IR, as compared to 6,501 (44.2 %) of the 14,710 women with DCIS who underwent mastectomy underwent IR. In a multivariable model for IBC, increasing age, black race, being married, rural location, and increased comorbidities were associated with decreased IR. Odds ratios (OR) of IR increased with commercial insurance (OR 3.38) and Medicare (OR 1.66) insurance (vs. self-pay), high surgeon-volume (OR 1.19), high hospital-volume (OR 2.24), and large hospital size (OR 1.20). The results were identical for DCIS, and by age category. The absolute difference between the proportion of patients who received IR with commercial insurance compared to other insurance, increased over time. Immediate in-hospital complication rates were higher for flap reconstruction compared to implant or no reconstruction (15.2, 4.0, and 6.1 %, respectively, P <.0001). IR has increased significantly over time; however, modifiable factors such as insurance status, hospital size, hospital location, and physician volume strongly predict IR. Public policy should ensure that access to reconstructive surgery is universally available.
PMCID: PMC3651032  PMID: 23053659
Breast reconstruction; Insurance; Hospital volume
5.  A randomized phase II of gemcitabine and sorafenib versus sorafenib alone in patients with metastatic pancreatic cancer 
Investigational new drugs  2011;30(3):1175-1183.
Patients with metastatic pancreatic cancer have limited therapeutic options. The role of the Ras-Raf-MAPK pathway and of vascular endothelial growth factor in pancreatic carcinogenesis provided the rational to evaluate the efficacy of sorafenib with or without gemcitabine in a randomized phase II study.
Patients with metastatic pancreatic cancer were randomized to sorafenib alone (arm A) or sorafenib with gemcitabine (arm B).
Arm A was closed to accrual at interim analysis due to the lack of objective response. Median PFS and OS were 2.3 and 4.3 months respectively. There was one partial response among the 37 patients in arm B. Median PFS and OS were 2.9 and 6.5 months respectively. There were more grade 3 and 4 toxicities in arm B with the most common being neutropenia (17%), thrombocytopenia (8%), alkaline phosphatase elevation (14%), venous thromboembolism (8%), diarrhea, hypokalemia and ALT elevation (5%) each. Several associations were noted between single nucleotide polymorphisms in ribonucleotide reductase, Cox-2, vascular endothelial growth factor and survival in patients treated with gemcitabine and sorafenib.
Neither sorafenib alone or sorafenib in combination with gemcitabine manifested promising activity in metastatic pancreatic cancer.
PMCID: PMC3745766  PMID: 21424698
Pancreatic cancer; Sorafenib; Gemcitabine; Ribonulceotide reductase
9.  Phase I trial of sorafenib in patients with recurrent or progressive malignant glioma 
Neuro-Oncology  2011;13(12):1324-1330.
Sorafenib is an inhibitor of multiple kinases that has demonstrated antiproliferative and antiangiogenic activity in a number of in vitro and in vivo model systems. A phase I study was conducted to determine the maximum tolerated dose (MTD) of sorafenib in patients with recurrent malignant glioma. Sorafenib was given orally, twice a day (BID), continuously in 28-day cycles. The dose was escalated in 2 groups of patients stratified by use of enzyme-inducing antiseizure drugs (±EIASDs). Dose-limiting toxicity (DLT) was defined as any grades 3–4 nonhematological toxicity, grade 4 hematological toxicity, and febrile neutropenia. The number of evaluable patients enrolled in the +EIASD and −EIASD arms were 23 and 24, respectively. DLTs were predominantly dermatological and gastrointestinal effects, as observed in previous clinical trials of sorafenib. The MTD was 600 mg BID for patients receiving EIASDs and 800 mg BID for those who were not. The plasma pharmacokinetics of sorafenib were not significantly affected by the concurrent administration of EIASDs. The MTD of sorafenib given orally BID on a continuous basis was established as 600 mg BID in patients with malignant glioma who were concurrently receiving EIASDs and 800 mg BID in those who were not. Further evaluation is warranted of sorafenib at the recommended MTD against recurrent or progressive malignant glioma in combination with other molecularly targeted drugs or in the newly diagnosed setting concurrent with chemoradiation.
PMCID: PMC3223097  PMID: 21954442
angiogenesis; glioma; pharmacokinetics; proliferation; targeted therapy
10.  Rescue of the murine amelogenin null phenotype with two amelogenin transgenes 
European Journal of Oral Sciences  2011;119(Suppl 1):70-74.
The amelogenin proteins are required for normal enamel development; the most abundant amelogenins expressed from alternatively spliced mRNAs are M180 and leucine rich amelogenin protein (LRAP). The Amelx null (KO) mouse has an enamel defect similar to human X-linked amelogenesis imperfecta. The disorganized enamel layer in KO mice is 10–20% the thickness of wild-type (WT) enamel and lacks prismatic structures. When the KO mice were mated with mice that express TgM180-87, partial rescue of the phenotype was observed such that enamel thickness, volume and density increased. A second transgene was introduced by mating the TgM180KO mice with TgLRAP mice, and male offspring were characterized for genotype and tooth phenotype was evaluated by SEM. TgM180LRAPKO molar enamel thickness further increased, and the structure was improved, with a more defined decussation pattern compared to singly rescued mice. We conclude that TgM180 provides significant rescue of the KO phenotype. Although the effectiveness of TgLRAP to rescue by itself is less obvious, the addition of TgLRAP to TgM180 in KO enamel leads to added improvement in both amount and structure and thus these transgenes function in a complementary manner. Together the two most abundant amelogenins lead to formation of obvious enamel decussation patterns.
PMCID: PMC3270886  PMID: 22243230
amelogenin; transgenic mice; amelogenesis imperfecta; phenotypic rescue
11.  The role of amelogenin during enamel crystallite growth and organization in vivo 
European Journal of Oral Sciences  2011;119(Suppl 1):65-69.
Amelogenin is critical for enamel formation and human AMELX gene mutations cause hypoplastic and/or hypomaturation enamel phenotypes. The Amelx null (AKO) mouse has a severe hypoplastic phenotype. This study evaluated the effect of amelogenin loss on enamel formation and crystallite morphology. Enamel from AKO and wild type (WT) mice was used. AKO mice were mated with transgenic mice expressing the most abundant known amelogenin isoform TgM180-87 to rescue (KOM180-87) the enamel crystallite phenotype. Molar enamel was embedded, sectioned with a diamond microtome and photographed using transmission electron microscopy. Crystallite sizes from multiple sections were measured using Image J. Crystallite mean thicknesses were (WT = 26 nm, AKO = 16 nm, KOm180-87 = 25 nm) and the mean widths were (WT = 96 nm, AKO = 59 nm, KOm180-87 = 85 nm). Despite a complete loss of amelogenin in AKO mice, a mineralized enamel layer with well-defined and organized crystallites forms. Enamel crystallites forming in the absence of amelogenin were reduced in thickness and width. For the first time we show that introduction of the m180 amelogenin isoform into the AKO mouse through crossbreeding rescues the crystallite phenotype. We conclude that amelogenin is essential for the development of normal crystallite size.
PMCID: PMC3293103  PMID: 22243229
amelogenin; crystallite; transgenic mice; amelogenesis imperfecta
12.  Crystallization and preliminary X-ray diffraction analysis of the protease from Southampton norovirus complexed with a Michael acceptor inhibitor 
The crystallization of the recombinant protease from Southampton norovirus is described. Whilst the native crystals were found to diffract only to medium resolution (2.9 Å), cocrystals with a designed covalently bound inhibitor diffracted X-rays to 1.7 Å resolution.
Noroviruses are the predominant cause of human epidemic nonbacterial gastroenteritis. Viral replication requires a cysteine protease that cleaves a 200 kDa viral polyprotein into its constituent functional parts. Here, the crystallization of the recombinant protease from the Southampton norovirus is described. Whilst the native crystals were found to diffract only to medium resolution (2.9 Å), cocrystals of an inhibitor complex diffracted X-rays to 1.7 Å resolution. The polypeptide inhibitor (Ac-EFQLQ-propenyl ethyl ester) possesses an amino-acid sequence designed to match the substrate specificity of the enzyme, but was synthesized with a reactive Michael acceptor group at the C-terminal end.
PMCID: PMC3001671  PMID: 21045318
3C proteases; noroviruses; Michael acceptors; inhibitor complexes
15.  Safe, Long-term Hepatic Expression of Anti-HCV shRNA in a Nonhuman Primate Model 
Molecular Therapy  2012;20(9):1737-1749.
The hepatitis C virus (HCV) chronically infects 2% of the world population and effective treatment is limited by long duration and significant side-effects. Here, we describe a novel drug, intended as a “single-shot ” therapy, which expresses three short hairpin RNAs (shRNAs) that simultaneously target multiple conserved regions of the HCV genome as confirmed in vitro by knockdown of an HCV replicon system. Using a recombinant adeno-associated virus (AAV) serotype 8 vector for delivery, comprehensive transduction of hepatocytes was achieved in vivo in a nonhuman primate (NHP) model following a single intravenous injection. However, dose ranging studies performed in 13 NHP resulted in high-expression levels of shRNA from wild-type (wt) Pol III promoters and dose-dependent hepatocellular toxicity, the first demonstration of shRNA-related toxicity in primates, establishing that the hepatotoxicity arises from highly conserved features of the RNA interference (RNAi) pathway. In the second generation drug, each promoter was re-engineered to reduce shRNA transcription to levels that circumvent toxicity but still inhibit replicon activity. In vivo testing of this modified construct in 18 NHPs showed conservation of hepatocyte transduction but complete elimination of hepatotoxicity, even with sustained shRNA expression for 50 days. These data support progression to a clinical study for treatment of HCV infection.
PMCID: PMC3437581  PMID: 22735378
16.  In Vitro Characterization of the Activity of PF-05095808, a Novel Biological Agent for Hepatitis C Virus Therapy 
PF-05095808 is a novel biological agent for chronic hepatitis C virus (HCV) therapy. It comprises a recombinant adeno-associated virus (AAV) DNA vector packaged into an AAV serotype 8 capsid. The vector directs expression of three short hairpin RNAs (shRNAs) targeted to conserved regions of the HCV genome. These shRNAs are processed by the host cell into the small interfering RNAs which mediate sequence-specific cleavage of target regions. For small-molecule inhibitors the key screens needed to assess in vitro activity are well defined; we developed new assays to assess this RNA interference agent and so to understand its therapeutic potential. Following administration of PF-05095808 or corresponding synthetic shRNAs, sequence-specific antiviral activity was observed in HCV replicon and infectious virus systems. To quantify the numbers of shRNA molecules required for antiviral activity in vitro and potentially also in vivo, a universal quantitative PCR (qPCR) assay was developed. The number of shRNA molecules needed to drive antiviral activity proved to be independent of the vector delivery system used for PF-05095808 administration. The emergence of resistant variants at the target site of one shRNA was characterized. A novel RNA cleavage assay was developed to confirm the spectrum of activity of PF-05095808 against common HCV clinical isolates. In summary, our data both support antiviral activity consistent with an RNA interference mechanism and demonstrate the potential of PF-05095808 as a therapeutic agent for chronic HCV infection.
PMCID: PMC3294929  PMID: 22203606
17.  Severe Isospora (Cystoisospora) belli Diarrhea Preceding the Diagnosis of Human T-Cell-Leukemia-Virus-1-Associated T-Cell Lymphoma 
Isospora (Cystoisospora) belli diarrhea can sometimes be fulminant in immunocompromised patients. It is endemic in tropical and subtropical areas, and sporadic episodes have been reported in nonendemic areas in nursing homes, day-care centers, and psychiatric institutions. We describe isosporiasis in an HIV-negative Sudanese-American female who presented with a debilitating diarrheal illness and profound weight loss. Isospora belli was detected in her stool by modified acid-fast staining. Serologic testing was negative for HIV but positive for HTLV-1 infection. Treatment with TMP-SMZ led to improvement in her diarrhea which recurred after stopping antibiotics. Subsequently, she developed generalized lymphadenopathy which was diagnosed as ATLL on immunohistochemical staining. Chemotherapy was initiated, but her condition continued to worsen due to persistent diarrhea and resulting profound electrolyte abnormalities. The patient opted for comfort measures and died a few weeks later at a nursing facility. This case emphasizes that the detection of I. belli should trigger testing for HIV, HTLV-1, and other causes of immunocompromise. We suggest that treatment with TMP-SMZ should be initiated and continued for a prolonged period of time in immunocompromised patients with I. belli diarrhea.
PMCID: PMC3431052  PMID: 22953083
18.  Amelogenesis Imperfecta: Genotype-Phenotype Studies in 71 Families 
Cells, Tissues, Organs  2011;194(2-4):279-283.
Amelogenesis imperfecta (AI) represents hereditary conditions affecting the quality and quantity of enamel. Six genes are known to cause AI (AMELX, ENAM, MMP20, KLK4, FAM83H, and WDR72). Our aim was to determine the distribution of different gene mutations in a large AI population and evaluate phenotype-genotype relationships. Affected and unaffected family members were evaluated clinically and radiographically by one examiner. Genotyping was completed using genomic DNA obtained from blood or saliva. A total of 494 individuals were enrolled, with 430 (224 affected, 202 unaffected, and 4 not definitive) belonging to 71 families with conditions consistent with the diagnosis of AI. Diverse clinical phenotypes were observed (i.e. hypoplastic, hypocalcified, and hypomaturation). Genotyping revealed mutations in all 6 candidate genes. A molecular diagnosis was made in 132 affected individuals (59%) and in 26 of the families (37%). Mutations involved 12 families with FAM83H (46%), 6 families with AMELX (23%), 3 families with ENAM (11%), 2 families with KLK4 and MMP20 (8% for each gene), and 1 family with a WDR72 mutation (4%). Phenotypic variants were associated with allelic FAM83H and AMELX mutations. Two seemingly unrelated families had the same KLK4 mutation. Families affected with AI where candidate gene mutations were not identified could have mutations not identifiable by traditional gene sequencing (e.g. exon deletion) or they could have promoter sequence mutations not evaluated in this study. However, the results suggest that there remain new AI causative genes to be identified.
PMCID: PMC3178091  PMID: 21597265
Enamel; Amelogenesis imperfecta; Phenotype; Genotype; Gene; Mutation
19.  Safety of Liver Gene Transfer Following Peripheral Intravascular Delivery of Adeno-Associated Virus (AAV)-5 and AAV-6 in a Large Animal Model 
Human Gene Therapy  2010;22(7):843-852.
Intravascular delivery of adeno-associated virus (AAV) vector is commonly used for liver-directed gene therapy. In humans, the high prevalence of neutralizing antibodies to AAV-2 capsid and the wide cross-reactivity with other serotypes hamper vector transduction efficacy. Moreover, the safety of gene-based approaches depends on vector biodistribution, vector dose, and route of administration. Here we sought to characterize the safety of AAV-5 and AAV-6 for liver-mediated human factor IX (hFIX) expression in rabbits at doses of 1 × 1012 or 1 × 1013 viral genomes/kg. Circulating therapeutic levels of FIX were observed in both cohorts of AAV-6-hFIX, whereas for AAV-5-hFIX only the high dose was effective. Long-lasting inhibitory antibodies to hFIX were detected in three of the 10 AAV-6-injected animals but were absent in the AAV-5 group. Overall, vector shedding in the semen was transient and vector dose-dependent. However, the kinetics of clearance were remarkably faster for AAV-5 (3–5 weeks) compared with AAV-6 (10–13 weeks). AAV-6 vector sequences outside the liver were minimal at 20–30 weeks post-injection. In contrast, AAV-5 exhibited relatively high amounts of vector DNA in tissues other than the liver. Together these data are useful to further define the safety and potential for clinical translation of these AAV vectors.
In this study, Favaro and colleagues characterize the safety of AAV-5 and AAV-6 for liver-mediated human factor IX (hFIX) expression in rabbits at doses of 1 × 1012 and 1 × 1013 viral genomes/kg. Circulating therapeutic levels of FIX were observed in both AAV-6-hFIX cohorts, whereas for the AAV-5-hFIX cohorts only the high dose was effective. The authors also report that the kinetics of vector clearance from the semen were remarkably faster for AAV-5 (3–5 weeks) compared with AAV-6 (10–13 weeks).
PMCID: PMC3135234  PMID: 21126217
20.  Pharmacological Modulation of Humoral Immunity in a Nonhuman Primate Model of AAV Gene Transfer for Hemophilia B 
Molecular Therapy  2012;20(7):1410-1416.
Liver gene transfer for hemophilia B has shown very promising results in recent clinical studies. A potential complication of gene-based treatments for hemophilia and other inherited disorders, however, is the development of neutralizing antibodies (NAb) against the therapeutic transgene. The risk of developing NAb to the coagulation factor IX (F.IX) transgene product following adeno-associated virus (AAV)-mediated hepatic gene transfer for hemophilia is small but not absent, as formation of inhibitory antibodies to F.IX is observed in experimental animals following liver gene transfer. Thus, strategies to modulate antitransgene NAb responses are needed. Here, we used the anti-B cell monoclonal antibody rituximab (rtx) in combination with cyclosporine A (CsA) to eradicate anti-human F.IX NAb in rhesus macaques previously injected intravenously with AAV8 vectors expressing human F.IX. A short course of immunosuppression (IS) resulted in eradication of anti-F.IX NAb with restoration of plasma F.IX transgene product detection. In one animal, following IS anti-AAV6 antibodies also dropped below detection, allowing for successful AAV vector readministration and resulting in high levels (60% or normal) of F.IX transgene product in plasma. Though the number of animals is small, this study supports for the safety and efficacy of B cell-targeting therapies to eradicate NAb developed following AAV-mediated gene transfer.
PMCID: PMC3392987  PMID: 22565846
21.  Comparison of Trihalomethanes in Tap Water and Blood: A Case Study in the United States 
Environmental Health Perspectives  2012;120(5):661-667.
Background: Epidemiological studies have used various measures to characterize trihalomethane (THM) exposures, but the relationship of these indicators to exposure biomarkers remains unclear.
Objectives: We examined temporal and spatial variability in baseline blood THM concentrations and assessed the relationship between these concentrations and several exposure indicators (tap water concentration, water-use activities, multiroute exposure metrics).
Methods: We measured water-use activity and THM concentrations in blood and residential tap water from 150 postpartum women from three U.S. locations.
Results: Blood ΣTHM [sum of chloroform (TCM), bromodichloromethane (BDCM), dibromo-chloromethane (DBCM), and bromoform (TBM)] concentrations varied by site and season. As expected based on variable tap water concentrations and toxicokinetic properties, the proportion of brominated species (BDCM, DBCM, and TBM) in blood varied by site (site 1, 24%; site 2, 29%; site 3, 57%) but varied less markedly than in tap water (site 1, 35%; site 2, 75%; site 3, 68%). The blood–water ΣTHM Spearman rank correlation coefficient was 0.36, with correlations higher for individual brominated species (BDCM, 0.62; DBCM, 0.53; TBM, 0.54) than for TCM (0.37). Noningestion water activities contributed more to the total exposure metric than did ingestion, but tap water THM concentrations were more predictive of blood THM levels than were metrics that incorporated water use.
Conclusions: Spatial and temporal variability in THM concentrations was greater in water than in blood. We found consistent blood–water correlations across season and site for BDCM and DBCM, and multivariate regression results suggest that water THM concentrations may be an adequate surro-gate for baseline blood levels.
PMCID: PMC3346785  PMID: 22281753
blood THM; blood–water correlations; brominated THMs; noningestion water activities; trihalomethanes
22.  Microgenomics of Ameloblastoma 
Journal of Dental Research  2011;90(4):463-469.
Gene expression profiles of human ameloblastoma microdissected cells were characterized with the purpose of identifying genes and their protein products that could be targeted as diagnostic and prognostic markers as well as for potential therapeutic interventions. Five formalin-fixed, decalcified, paraffin-embedded samples of ameloblastoma were subjected to laser capture microdissection, linear mRNA amplification, and hybridization to oligonucleotide human 41,000 RNA arrays and compared with universal human reference RNA, to determine the gene expression signature. Assessment of the data by Significance Analysis of Microarrays (SAM) and cluster analysis showed that 38 genes were highly expressed (two-fold increase) in all samples, while 41 genes were underexpressed (two-fold reduction). Elements of the sonic hedgehog pathway and Wingless type MMTV integration site family were validated by immunohistochemistry. We have identified the expression of multiple genes and protein products that could serve as potential diagnostic, prognostic, and therapeutic targets.
PMCID: PMC3144135  PMID: 21282726
ameloblastoma; gene expression profile; human; microarray
23.  Nonnutritive, Low Caloric Substitutes for Food Sugars: Clinical Implications for Addressing the Incidence of Dental Caries and Overweight/Obesity 
Caries and obesity are two common conditions affecting children in the United States and other developed countries. Caries in the teeth of susceptible children have often been associated with frequent ingestion of fermentable sugars such as sucrose, fructose, glucose, and maltose. Increased calorie intake associated with sugars and carbohydrates, especially when associated with physical inactivity, has been implicated in childhood obesity. Fortunately, nonnutritive artificial alternatives and non-/low-caloric natural sugars have been developed as alternatives to fermentable sugars and have shown promise in partially addressing these health issues. Diet counseling is an important adjunct to oral health instruction. Although there are only five artificial sweeteners that have been approved as food additives by the Food and Drug Administration (FDA), there are additional five non-/low caloric sweeteners that have FDA GRAS (Generally Recognized as Safe) designation. Given the health impact of sugars and other carbohydrates, dental professionals should be aware of the nonnutritive non-/low caloric sweeteners available on the market and both their benefits and potential risks. Dental health professionals should also be proactive in helping identify patients at risk for obesity and provide counseling and referral when appropriate.
PMCID: PMC3296175  PMID: 22505906
24.  Characterization of a Recombinant Adeno-Associated Virus Type 2 Reference Standard Material 
Human Gene Therapy  2010;21(10):1273-1285.
Here, the AAV Reference Standard Working Group presents the results of their international collaboration to produce and characterize a recombinant AAV serotype 2 Reference Standard Material. The purpose of this material is to provide a universal standard for particle titer, vector genome titer, and infectious titer for AAV2 gene transfer vectors.
A recombinant adeno-associated virus serotype 2 Reference Standard Material (rAAV2 RSM) has been produced and characterized with the purpose of providing a reference standard for particle titer, vector genome titer, and infectious titer for AAV2 gene transfer vectors. Production and purification of the reference material were carried out by helper virus–free transient transfection and chromatographic purification. The purified bulk material was vialed, confirmed negative for microbial contamination, and then distributed for characterization along with standard assay protocols and assay reagents to 16 laboratories worldwide. Using statistical transformation and modeling of the raw data, mean titers and confidence intervals were determined for capsid particles ({X}, 9.18 × 1011 particles/ml; 95% confidence interval [CI], 7.89 × 1011 to 1.05 × 1012 particles/ml), vector genomes ({X}, 3.28 × 1010 vector genomes/ml; 95% CI, 2.70 × 1010 to 4.75 × 1010 vector genomes/ml), transducing units ({X}, 5.09 × 108 transducing units/ml; 95% CI, 2.00 × 108 to 9.60 × 108 transducing units/ml), and infectious units ({X}, 4.37 × 109 TCID50 IU/ml; 95% CI, 2.06 × 109 to 9.26 × 109 TCID50 IU/ml). Further analysis confirmed the identity of the reference material as AAV2 and the purity relative to nonvector proteins as greater than 94%. One obvious trend in the quantitative data was the degree of variation between institutions for each assay despite the relatively tight correlation of assay results within an institution. This relatively poor degree of interlaboratory precision and accuracy was apparent even though attempts were made to standardize the assays by providing detailed protocols and common reagents. This is the first time that such variation between laboratories has been thoroughly documented and the findings emphasize the need in the field for universal reference standards. The rAAV2 RSM has been deposited with the American Type Culture Collection and is available to the scientific community to calibrate laboratory-specific internal titer standards. Anticipated uses of the rAAV2 RSM are discussed.
PMCID: PMC2957240  PMID: 20486768
25.  Increased Diacylglycerols Characterize Hepatic Lipid Changes in Progression of Human Nonalcoholic Fatty Liver Disease; Comparison to a Murine Model 
PLoS ONE  2011;6(8):e22775.
Background and Aims
The spectrum of nonalcoholic fatty liver disease (NAFLD) includes steatosis, nonalcoholic steatohepatitis (NASH), and progression to cirrhosis. While differences in liver lipids between disease states have been reported, precise composition of phospholipids and diacylglycerols (DAG) at a lipid species level has not been previously described. The goal of this study was to characterize changes in lipid species through progression of human NAFLD using advanced lipidomic technology and compare this with a murine model of early and advanced NAFLD.
Utilizing mass spectrometry lipidomics, over 250 phospholipid and diacylglycerol species (DAGs) were identified in normal and diseased human and murine liver extracts.
Significant differences between phospholipid composition of normal and diseased livers were demonstrated, notably among DAG species, consistent with previous reports that DAG transferases are involved in the progression of NAFLD and liver fibrosis. In addition, a novel phospholipid species (ether linked phosphatidylinositol) was identified in human cirrhotic liver extracts.
Using parallel lipidomics analysis of murine and human liver tissues it was determined that mice maintained on a high-fat diet provide a reproducible model of NAFLD in regards to specificity of lipid species in the liver. These studies demonstrated that novel lipid species may serve as markers of advanced liver disease and importantly, marked increases in DAG species are a hallmark of NAFLD. Elevated DAGs may contribute to altered triglyceride, phosphatidylcholine (PC), and phosphatidylethanolamine (PE) levels characteristic of the disease and specific DAG species might be important lipid signaling molecules in the progression of NAFLD.
PMCID: PMC3153459  PMID: 21857953

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