P11.65.B GBM AGILE: A global, phase 2/3 adaptive platform trial to evaluate multiple treatment regimens in newly diagnosed and recurrent glioblastoma

Background

GBM AGILE (Glioblastoma Adaptive, Global, Innovative Learning Environment) is a biomarker based, multi-arm, international, seamless Phase 2/3 Response Adaptive Randomization platform trial designed to rapidly identify experimental therapies that improve overall survival and confirm efficacious experimental therapies and associated biomarker signatures to support new drug approvals and registration. It is a collaboration between academic investigators, patient organizations and industry, under the sponsorship of the non-profit organization, Global Coalition for Adaptive Research, to support new drug applications for newly diagnosed and recurrent GBM.

Material and Methods

The primary objective of GBM AGILE is to identify therapies that effectively improve overall survival in patients with newly diagnosed or recurrent GBM. Bayesian response adaptive randomization is used within subtypes of the disease to assign participants to investigational arms based on their performance. Operating under a master protocol, GBM AGILE allows multiple drugs from different pharmaceutical companies to be evaluated simultaneously and/or over time against a common control arm. Based on performance, a drug may graduate and move to a Stage 2 (Phase 3) within the trial, and the totality of the data can be used for a new drug application and registration process. New experimental therapies are added as information about promising new drugs is identified while other therapies are removed as they complete their evaluation. The master protocol/ trial infrastructure includes efficiencies through an adaptive trial design, shared control arm and operational processes such as risk-based monitoring and enhanced remote activities. With its adaptable structure, GBM AGILE has continued trial activation, inclusion of new investigational therapies, and enrollment globally through the challenges of a global pandemic.GBM AGILE provides an efficient mechanism to screen and develop robust information regarding the efficacy of proposed novel therapeutics and associated biomarkers for GBM and to quickly move therapies and biomarkers into clinic. GBM AGILE received initial approval from the United States FDA in April 2019, and in Europe through the Voluntary Harmonization Procedure (VHP) in April, 2021. As of 2022, AGILE has screened over 1000 patients studying multiple investigational treatments. Enrollment rates are 3 to 4 times greater than traditional GBM trials, with active sites averaging 0.75 to 1 patients/site/month.

Currently, there are 41 sites activated in the US, 4 in Canada and 2 in Switzerland and an estimated 24 sites yet to open in Germany, France, Switzerland, Italy and Austria. In addition to the continued expansion in Europe, effort is undergoing to extend the trial to China and Australia as well. Clinical trial information: NCT03970447

A Round Trip to the Desert: In situ Nanopore Sequencing Informs Targeted Bioprospecting

Bioprospecting expeditions are often performed in remote locations, in order to access previously unexplored samples. Nevertheless, the actual potential of those samples is only assessed once scientists are back in the laboratory, where a time-consuming screening must take place. This work evaluates the suitability of using Nanopore sequencing during a journey to the Tabernas Desert (Spain) for forecasting the potential of specific samples in terms of bacterial diversity and prevalence of radiation- and desiccation-resistant taxa, which were the target of the bioprospecting activities. Samples collected during the first day were analyzed through 16S rRNA gene sequencing using a mobile laboratory. Results enabled the identification of locations showing the greatest and the least potential, and a second, informed sampling was performed focusing on those sites. After finishing the expedition, a culture collection of 166 strains belonging to 50 different genera was established. Overall, Nanopore and culturing data correlated well, since samples holding a greater potential at the microbiome level also yielded a more interesting set of microbial isolates, whereas samples showing less biodiversity resulted in a reduced (and redundant) set of culturable bacteria. Thus, we anticipate that portable sequencers hold potential as key, easy-to-use tools for in situ-informed bioprospecting strategies.

The microbial terroir: open questions on the Nagoya protocol applied to microbial resources

The Nagoya Protocol on Access and Benefit‐sharing (https://www.cbd.int/abs/), primarily designed for vascular plant and animal resources, is also extended to the use of microbial resources, but its application to the microbiological realm has raised many doubts and provoked criticisms. This is because of the particularities of microbial ecology and the technical and legal difficulties encompassed in its application.

Extremophilic microbial communities on photovoltaic panel surfaces: a two-year study

Solar panel surfaces can be colonized by microorganisms adapted to desiccation, temperature fluctuations and solar radiation. Although the taxonomic and functional composition of these communities has been studied, the microbial colonization process remains unclear. In the present work, we have monitored this microbial colonization process during 24 months by performing weekly measurements of the photovoltaic efficiency, carrying out 16S rRNA gene high-throughput sequencing, and studying the effect of antimicrobial compounds on the composition of the microbial biocenosis. This is the first time a long-term study of the colonization process of solar panels has been performed, and our results reveal that species richness and biodiversity exhibit seasonal fluctuations and that there is a trend towards an increase or decrease of specialist (solar panel-adapted) and generalist taxa, respectively. On the former, extremophilic bacterial genera Deinococcus, Hymenobacter and Roseomonas and fungal Neocatenulostroma, Symmetrospora and Sporobolomyces tended to dominate the biocenosis; whereas Lactobacillus sp or Stemphyllium exhibited a decreasing trend. This profile was deeply altered by washing the panels with chemical agents (Virkon), but this did not lead to an increase of the solar panels efficiency. Our results show that solar panels are extreme environments that force the selection of a particular microbial community.

Sphingomonas solaris sp. nov., isolated from a solar panel in Boston, Massachusetts

Solar panel surfaces, although subjected to a range of extreme environmental conditions, are inhabited by a diverse microbial community adapted to solar radiation, desiccation and temperature fluctuations. This is the first time a new bacterial species has been isolated from this environment. Strain R4DWN^T belongs to the genus Sphingomonas and was isolated from a solar panel surface in Boston, MA, USA. Strain R4DWN^T is a Gram-negative, non-motile and rod-shaped bacteria that tested positive for oxidase and catalase and forms round-shaped, shiny and orange-coloured colonies. It is mesophilic, neutrophilic and non-halophilic, and presents a more stenotrophic metabolism than its closest neighbours. The major fatty acids in this strain are C_18:1ω7c/C_18:1ω6c, C_16:1ω7c/C_16:1ω6c, C_14:0 2OH and C_16:0. Comparison of 16S rRNA gene sequences revealed that the closest type strains to R4DWN^T are Sphingomonas fennica, Sphingomonas formosensis, Sphingomonas prati, Sphingomonas montana and Sphingomonas oleivorans with 96.3, 96.1, 96.0, 95.9 and 95.7 % pairwise similarity, respectively. The genomic G+C content of R4DWN^T is 67.9 mol%. Based on these characteristics, strain R4DWN^T represents a novel species of the genus Sphingomonas for which the name Sphingomonas solaris sp. nov. is proposed with the type strain R4DWN^T (=CECT 9811^T=LMG 31344^T).

Microbial communities of the Mediterranean rocky shore: ecology and biotechnological potential of the sea-land transition

Microbial communities from harsh environments hold great promise as sources of biotechnologically relevant strains and compounds. In the present work, we have characterized the microorganisms from the supralittoral and splash zone in three different rocky locations of the Western Mediterranean coast, a tough environment characterized by high levels of irradiation and large temperature and salinity fluctuations. We have retrieved a complete view of the ecology and functional aspects of these communities and assessed the biotechnological potential of the cultivable microorganisms. All three locations displayed very similar taxonomic profiles, with the genus Rubrobacter and the families Xenococcaceae, Flammeovirgaceae, Phyllobacteriaceae, Rhodobacteraceae and Trueperaceae being the most abundant taxa; and Ascomycota and halotolerant archaea as members of the eukaryotic and archaeal community respectively. In parallel, the culture-dependent approach yielded a 100-isolates collection, out of which 12 displayed high antioxidant activities, as evidenced by two in vitro (hydrogen peroxide and DPPH) and confirmed in vivo with Caenorhabditis elegans assays, in which two isolates, CR22 and CR24, resulted in extended survival rates of the nematodes. This work is the first complete characterization of the Mediterranean splash-zone coastal microbiome, and our results indicate that this microbial niche is home of an extremophilic community that holds biotechnological potential.

Rationale and design of a pilot study to evaluate the acceptability and effectiveness of a revised protein sparing modified fast (rPSMF) for severe obesity in a pediatric tertiary care weight management clinic

Aggressive dietary interventions may provide an accessible treatment option for children and adolescents with severe obesity who are not successful with traditional lifestyle behavioral interventions or do not want or qualify for weight loss surgery. One such intensive dietary option is the protein sparing modified fast (PSMF). The PSMF involves minimal carbohydrate intake to induce ketosis, while maintaining adequate or high protein intake to minimize catabolism. The PSMF, under medical supervision, can be an effective and safe intervention for children and adolescents, yet the PSMF diet is not regularly used in the treatment of pediatric severe obesity. This paper describes the rationale and design for a pilot study to evaluate the acceptability and effectiveness of a revised PSMF (rPSMF) implemented as a weight loss treatment option for children and adolescents with severe obesity in a pediatric tertiary care weight management clinic. The primary aim of the study is to evaluate the acceptability of the rPSMF as assessed by adherence, satisfaction with the intervention, and participation rate using quantitative and qualitative methods. The secondary aim is to investigate the effectiveness of the rPSMF on improving a) anthropometric measures (weight, body mass index [BMI], BMI z-score); b) metabolic measures (lipid profile, glycosylated hemoglobin, liver function tests); and c) quality of life. Results of this study will provide guidance for the standardization of a pediatric rPSMF protocol in a clinic setting, delineate which factors improve or hinder adherence and weight loss and provide preliminary data for a multicenter randomized controlled trial.

Clinicaltrialsgov identifier

NCT03899311.

Bioprospecting the Solar Panel Microbiome: High-Throughput Screening for Antioxidant Bacteria in a Caenorhabditis elegans Model

Microbial communities that are exposed to sunlight typically share a series of adaptations to deal with the radiation they are exposed to, including efficient DNA repair systems, pigment production and protection against oxidative stress, which makes these environments good candidates for the search of novel antioxidant microorganisms. In this research project, we isolated potential antioxidant pigmented bacteria from a dry and highly-irradiated extreme environment: solar panels. High-throughput in vivo assays using Caenorhabditis elegans as an experimental model demonstrated the high antioxidant and ultraviolet-protection properties of these bacterial isolates that proved to be rich in carotenoids. Our results suggest that solar panels harbor a microbial community that includes strains with potential applications as antioxidants.

Microbial Ecology on Solar Panels in Berkeley, CA, United States

Solar panels can be found practically all over the world and represent a standard surface that can be colonized by microbial communities that are resistant to harsh environmental conditions, including high irradiation, temperature fluctuations and desiccation. These properties make them not only ideal sources of stress-resistant bacteria, but also standard devices to study the microbial communities and their colonization process from different areas of Earth. We report here a comprehensive description of the microbial communities associated with solar panels in Berkeley, CA, United States. Cultivable bacteria were isolated to characterize their adhesive capabilities, and UV- and desiccation-resistance properties. Furthermore, a parallel culture-independent metagenomic and metabolomic approach has allowed us to gain insight on the taxonomic and functional nature of these communities. Metagenomic analysis was performed using the Illumina HiSeq2500 sequencing platform, revealing that the bacterial population of the Berkeley solar panels is composed mainly of Actinobacteria, Bacteroidetes and Proteobacteria, as well as lower amounts of Deinococcus-Thermus and Firmicutes. Furthermore, a clear predominance of Hymenobacter sp. was also observed. A functional analysis revealed that pathways involved in the persistence of microbes on solar panels (i.e., stress response, capsule development, and metabolite repair) and genes assigned to carotenoid biosynthesis were common to all metagenomes. On the other hand, genes involved in photosynthetic pathways and general autotrophic subsystems were rare, suggesting that these pathways are not critical for persistence on solar panels. Metabolomics was performed using a liquid chromatography tandem mass spectrometry (LC-MS/MS) approach. When comparing the metabolome of the solar panels from Berkeley and from Valencia (Spain), a very similar composition in polar metabolites could be observed, although some metabolites appeared to be differentially represented (for example, trigonelline, pantolactone and 5-valerolactone were more abundant in the samples from Valencia than in the ones from Berkeley). Furthermore, triglyceride metabolites were highly abundant in all the solar panel samples, and both locations displayed similar profiles. The comparison of the taxonomic profile of the Californian solar panels with those previously described in Spain revealed striking similarities, highlighting the central role of both selective pressures and the ubiquity of microbial populations in the colonization and establishment of microbial communities.

Polar solar panels: Arctic and Antarctic microbiomes display similar taxonomic profiles

Solar panels located on high (Arctic and Antarctic) latitudes combine the harshness of the climate with that of the solar exposure. We report here that these polar solar panels are inhabited by similar microbial communities in taxonomic terms, dominated by Hymenobacter spp., Sphingomonas spp. and Ascomycota. Our results suggest that solar panels, even on high latitudes, can shape a microbial ecosystem adapted to irradiation and desiccation.

CPT1A methylation is associated with plasma adiponectin

BACKGROUND AND AIMS

Adiponectin, an adipose-secreted protein that has been linked to insulin sensitivity, plasma lipids, and inflammatory patterns, is an established biomarker for metabolic health. Despite clinical relevance and high heritability, the determinants of plasma adiponectin levels remain poorly understood.

METHODS AND RESULTS

We conducted the first epigenome-wide cross-sectional study of adiponectin levels using methylation data on 368,051 cytosine-phosphate-guanine (CpG) sites in CD4+ T-cells from the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN, n = 991). We fit linear mixed models, adjusting for age, sex, study site, T-cell purity, and family. We have identified a positive association (regression coefficient ± SE = 0.01 ± 0.001, P = 3.4 × 10^-13) between plasma adiponectin levels and methylation of a CpG site in CPT1A, a key player in fatty acid metabolism. The association was replicated (n = 474, P = 0.0009) in whole blood samples from the Amish participants of the Heredity and Phenotype Intervention (HAPI) Heart Study as well as White (n = 592, P = 0.0005) but not Black (n = 243, P = 0.18) participants of the Bogalusa Heart Study (BHS). The association remained significant upon adjusting for BMI and smoking in GOLDN and HAPI but not BHS. We also identified associations between methylation loci in RNF145 and UFM1 and plasma adiponectin in GOLDN and White BHS participants, although the association was not robust to adjustment for BMI or smoking.

CONCLUSION

We have identified and replicated associations between several biologically plausible loci and plasma adiponectin. These findings support the importance of epigenetic processes in metabolic traits, laying the groundwork for future translational applications.

Abstract P5-06-05: Preclinical characterization of VX-984, a selective DNA-dependent protein kinase (DNA-PK) inhibitor in combination with doxorubicin in breast and ovarian cancers

Background: The efficacy of chemotherapeutic agents such as doxorubicin, which cause lethal DNA double-strand breaks (DSBs), is diminished by efficient repair of the damaged DNA in cancer cells. DNA-PK is a key regulator of the non-homologous end joining (NHEJ) pathway, which is responsible for repairing DSBs. Studies of nonselective inhibitors of DNA-PK have shown that cancer cells depend on DNA-PK for survival following treatment with DSB-inducing agents. However, a comprehensive characterization of DNA-PK inhibition has been hampered by a lack of selective inhibitors. Here we describe VX-984, a potent and selective inhibitor of DNA-PK, and its preclinical profile in combination with doxorubicin both in vitro and in vivo.

Methods: VX-984 was examined as a single agent and in combination with doxorubicin or pegylated liposomal doxorubicin (PLD) in a panel of breast cancer cell lines and in mouse xenograft models, respectively.

Results: In vitro, inhibition of DNA-PK by VX-984 enhanced the cytotoxic activity of doxorubicin in established breast cancer cell lines and in primary ovarian tumor explants. Notably, mean Bliss DE >10% (strong synergy) were observed for doxorubicin in the presence of VX-984 in 22 of 35 breast cancer cell lines and 21 of 44 ovarian cancer cell lines in a broad cancer cell line screen. Further, the efficacy observed with VX-984 was associated with increased DNA damage as measured by phosphorylated histone H2AX (gamma-H2AX) and phosphorylated Kruppel-associated protein (pKAP1) in DU4475, MDA-MB-436 and MDA-MB-468 breast cancer cell lines, which is consistent with diminished DSB repair. In vivo, VX-984 significantly enhanced the efficacy of PLD in ovarian cancer patient-derived xenograft models and in cell line xenograft models.

Conclusions: These data provide evidence that inhibition of DNA-PK by VX-984 enhances the efficacy of doxorubicin in preclinical models and support the use of VX-984 in combination with DSB agents such as anthracyclines including PLD for the treatment of breast and ovarian cancers. VX-984 is currently in a Phase 1 clinical trial in combination with PLD.

Sponsored by Vertex Pharmaceuticals Incorporated.

Citation Format: Boucher D, Newsome D, Takemoto D, Hillier S, Wang Y, Arimoto R, Maxwell J, Charifson P, Fields SZ, Tanner K, Penney MS. Preclinical characterization of VX-984, a selective DNA-dependent protein kinase (DNA-PK) inhibitor in combination with doxorubicin in breast and ovarian cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-06-05.

Prospective Evaluation of Genetic Variation in Platelet Endothelial Aggregation Receptor 1 Reveals Aspirin-Dependent Effects on Platelet Aggregation Pathways

Genetic variation in the platelet endothelial aggregation receptor 1 (PEAR1) gene, most notably rs12041331, is implicated in altered on‐aspirin platelet aggregation and increased cardiovascular event risk. We prospectively tested the effects of aspirin administration at commonly prescribed doses (81, 162, and 324 mg/day) on agonist‐induced platelet aggregation by rs12041331 genotype in 67 healthy individuals. Prior to aspirin administration, rs12041331 minor allele carriers had significantly reduced adenosine diphosphate (ADP)‐induced platelet aggregation compared with noncarriers (P = 0.03) but was not associated with other platelet pathways. In contrast, rs12041331 was significantly associated with on‐aspirin platelet aggregation when collagen and epinephrine were used to stimulate platelet aggregation (P < 0.05 for all associations), but not ADP. The influence of PEAR1 rs12041331 on platelet aggregation is pathway‐specific and is altered by aspirin at therapeutic doses, but not in a dose‐dependent manner. Additional studies are needed to determine the impact of PEAR1 on cardiovascular events in aspirin‐treated patients.

Standards not that standard

There is a general assent on the key role of standards in Synthetic Biology. In two consecutive letters to this journal, suggestions on the assembly methods for the Registry of standard biological parts have been described. We fully agree with those authors on the need of a more flexible building strategy and we highlight in the present work two major functional challenges standardization efforts have to deal with: the need of both universal and orthogonal behaviors. We provide experimental data that clearly indicate that such engineering requirements should not be taken for granted in Synthetic Biology.

Paraoxonase 1 (PON1) gene variants are not associated with clopidogrel response

A common functional variant in paraoxonase 1 (PON1), Q192R, was recently reported to be a major determinant of clopidogrel response. This variant was genotyped in 566 participants of the Amish Pharmacogenomics of Anti-Platelet Intervention (PAPI) study and in 227 percutaneous coronary intervention (PCI) patients. Serum paraoxonase activity was measured in a subset of 79 PAPI participants. PON1 Q192R was not associated with pre- or post-clopidogrel platelet aggregation in the PAPI study (P = 0.16 and P = 0.21, respectively) or the PCI cohort (P = 0.47 and P = 0.91, respectively). The Q192 allele was not associated with cardiovascular events (hazard ratio (HR) 0.46, 95% confidence interval (CI) 0.20-1.06; P = 0.07). No correlation was observed between paraoxonase activity and post-clopidogrel platelet aggregation (r(2) < 0.01, P = 0.78). None of 49 additional PON1 variants evaluated was associated with post-clopidogrel platelet aggregation. These findings do not support a role for PON1 as a determinant of clopidogrel response.

Predicting outcome in ex-premature infants supported with extracorporeal membrane oxygenation for acute hypoxic respiratory failure

OBJECTIVE

To identify predictors of outcome in ex-premature infants supported with extracorporeal membrane oxygenation (ECMO) for acute hypoxic respiratory failure.

METHODS

Retrospective review of ex-premature infants with acquired acute hypoxic respiratory failure requiring ECMO support in the United Kingdom from 1992 to 2001. Review of follow up questionnaires completed by general practitioners and local paediatricians.

RESULTS

Sixty four ex-premature infants (5-10 each year) received ECMO support, despite increased use of advanced conventional treatments over the decade. The most common infective agent was respiratory syncytial virus (85% of cases). Median birth gestation was 29 weeks and median corrected age at the time of ECMO support was 42 weeks. Median ECMO support duration was relatively long, at 229 hours. Survival to hospital discharge and to 6 months was 80%, remaining similar throughout the period of review. At follow up, 60% had long term neurodisability and 79% had chronic pulmonary problems. Of pre-ECMO factors, baseline oxygen dependence, younger age, and inpatient status were associated with non-survival (p < or = 0.05). Of ECMO related factors, patient complications were independently associated with adverse neurodevelopmental outcome and death (p < 0.01).

CONCLUSIONS

Survival rates for ex-premature infants after ECMO support are favourable, but patients suffer a high burden of morbidity during intensive care and over the long term. At the time of ECMO referral, baseline oxygen dependence is the most important predictor of death, but no combination of the factors considered was associated with a mortality that would preclude ECMO support.

Molecular scanning for mutations in the insulin receptor substrate-1 (IRS-1) gene in Mexican Americans with Type 2 diabetes mellitus

BACKGROUND

Insulin receptor substrate-1 (IRS-1) is an endogenous substrate for the insulin receptor tyrosine kinase, which plays an important role in insulin signaling. Mutations in the IRS-1 gene are associated in some populations with obesity and Type 2 diabetes.

METHODS

To determine whether variation in the IRS-1 gene contributes to genetic susceptibility to insulin resistance and Type 2 diabetes in Mexican Americans, the entire coding region of the IRS-1 gene was screened for variation in 31 unrelated subjects with Type 2 diabetes using single-stranded conformational polymorphism analysis (SSCP) and dideoxy sequence analysis. Variants encoding amino acid substitutions were genotyped in 27 unrelated nondiabetic Mexican Americans and in all family members of subjects containing these variants, and association analyses were performed. To trace the ancestral origins of the variants, Iberian Caucasians and Pima Indians were also genotyped.

RESULTS

Eight single base changes were found: four silent polymorphisms and four missense mutations (Ala94Thr, Ala512Pro, Ser892Gly and Gly971Arg). Allele frequencies were 0.009, 0.017, 0.017 and 0.043, respectively. There were no significant associations of any of these variants with diabetes, glucose or insulin levels during an oral glucose tolerance test, or with body mass index (BMI) in Mexican American families except for a modest association between the Ala94Thr variant and decreased BMI (30.4 kg/m(2) vs 24.0 kg/m(2); p=0.035). None of these four missense mutations were detected in Pima Indians. In Iberian Caucasians, neither Ala94Thr nor Ser892Gly were detected, and Ala512Pro was detected in only 0/60 diabetic patients and 1/60 nondiabetic controls. Gly971Arg was relatively more common in Iberian Caucasians with 12/58 diabetic patients and 7/60 nondiabetic controls being heterozygous for this variant (p=0.21 for comparison between diabetic and nondiabetic subjects).

CONCLUSIONS

Ala94Thr, Ala512Pro and Ser892Gly mutation are rare in the populations studied. Gly971Arg, is more common in Mexican Americans and Caucasians, but is not a major contributor to genetic susceptibility to Type 2 diabetes.

Mechanical sensitization of cutaneous C-fiber nociceptors by prostaglandin E2 in the rat

While it is generally assumed that nociceptor sensitization underlies peripheral hyperalgesia, there is disagreement regarding the ability of inflammatory mediators to sensitize nociceptors to mechanical stimuli. In this in vivo electrophysiological study, mechanical threshold and response to sustained threshold and sustained suprathreshold mechanical stimuli were measured before and after intradermal administration of prostaglandin E2 (PGE2) into the receptive field of cutaneous C-fiber nociceptors in the rat. PGE2 produced a decrease in mechanical threshold and an increase in response to sustained threshold but not sustained suprathreshold mechanical stimulation. These data suggest that while inflammatory mediators produce a decrease in mechanical threshold and/or an increase in number of action potentials to sustained threshold stimuli, they do not increase the maximal response to mechanical stimuli in C-fiber nociceptors.

Competitive reverse-transcriptase polymerase chain reaction without an artificial internal standard

Advances in our understanding of molecular and cellular physiology necessitate that mRNA levels for specific growth factors and other rare transcripts be measured quantitatively in small samples. Conventional methods such as Northern blot analysis and solution hybridization/ribonuclease protection are not sufficiently sensitive. We now report the theory, development, and validation of a rapid and highly sensitive assay, the RNA/DNA quantitative polymerase chain reaction (RD-PCR), which uses a competitive PCR approach to measure the number of copies of a specific mRNA per cell. Total nucleic acid (RNA and genomic DNA) is isolated from cells in culture. The mRNA of interest is first reverse-transcribed with an oligomer bearing a complementary sequence specific for the mRNA at its 3'-end, and a sequence complementary to an intron of the desired gene at the 5'-end. Competitive PCR is then performed in the presence of the cDNA product and endogenous genomic DNA, with an upstream primer complementary to the exon sequence of the gene of interest, and a downstream primer complementary to the intron sequence that was tagged to the cDNA. The cell's own genomic DNA is thereby used as the internal standard. To control for the efficiency of reverse transcription, a standard curve is used in each assay. The technique was validated by comparing the quantitation of insulin-like growth factor I (IGF-I) mRNA in two human cell lines by RD-PCR and by RNase protection analysis. Both methods gave similar numbers of copies of IGF-I mRNA per cell. For accurate analysis, RNase protection required at least 10(7) cells; RD-PCR required as little as 10(2) cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The two nonallelic Xenopus insulin genes are expressed coordinately in the adult pancreas

We have previously shown that the two nonallelic insulin genes in Xenopus laevis are expressed differentially during neurulation in prepancreatic embryos (Shuldiner et al., 1991, Proc. Natl. Acad. Sci. USA 88, 7679-7683). We now examine pancreatic expression with alterations in ambient temperature, glucose administration, fasting and feeding, somatostatin analog treatment, as well as during postmetamorphic growth. Insulin I and II mRNAs were quantitated by slot blot hybridization with specific probes and were expressed as the number of copies (x 10(8)) per 5 micrograms total RNA +/- SEM. Frogs maintained at 12 degrees showed no significant changes when compared to frogs maintained at 20 degrees. There was a coordinate decrease in insulin I and II mRNA levels in frogs maintained at 29 degrees (Ins I 20, 3.41 +/- 0.34 vs Ins I 29, 2.39 +/- 0.17; Ins II 20, 2.59 +/- 0.36 vs Ins II 29, 1.67 +/- 0.09; P < 0.05). When compared to fasting animals, both insulin I and II mRNA levels decreased slightly in frogs given repeated intraperitoneal injections of glucose and in those fed ad libitum; there were no changes after a single dose of glucose or in frogs given somatostatin. When compared to young frogs (6 to 24 months), older frogs (36 months) had higher insulin I and II mRNA levels (e.g., Ins I 6mo, 2.14 +/- 0.15 vs Ins I 36mo, 3.68 +/- 0.43; Ins II 6mo, 1.21 +/- 0.06 vs Ins II 36mo, 3.26 +/- 0.38; P < 0.05). Further, there was a modest reduction in the percentage of insulin I mRNA with aging (e.g., 6 months 63.6 +/- 3.1% vs 36 months 53.9 +/- 2.7%; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Knowledge about and attitude to HIV/AIDS among dentists and dental assistants in Budapest, November 1992]

118 Dentists and 115 Dental Nurses opinion was evaluated about their knowledges and attitudes to HIV/AIDS problem in Budapest (Hungary) 1992 November. The frequency of false knowledges about the transmission was 5-10%. More than 70% of the asked persons changed their habits in working place and 62% of dentists and 78% of nurses uses rubber gloves. 2.5% of the dentists and 7.8% of nurses thinks they will refuse the treatment of a HIV/AIDS patient. Most informations collected the doctors from professional literature and the nurses from mass medias, the mention of postgraduate trainings was low. Above data are valid for those persons who are working in the state health care system. Data of the private practice will be collected and analysed in the future.

RNA template-specific PCR: an improved method that dramatically reduces false positives in RT-PCR

We report a novel modification of the reverse transcription PCR method, designated RNA template-specific PCR. With this approach, the 5' end of the first strand is tagged with a unique nucleotide sequence during reverse transcription that may then be exploited to amplify preferentially RNA-derived sequences. In our hands, RNA template-specific PCR retains the sensitivity of the traditional method, but greatly reduces the frequency of false positives, and virtually eliminates carryover contamination from PCR products amplified in previous experiments.

Ligase-free subcloning: a versatile method to subclone polymerase chain reaction (PCR) products in a single day

Often, it is convenient to subclone polymerase chain reaction (PCR) products into a plasmid vector for subsequent replication in bacteria, but conventional subcloning methods often fail. We report a rapid and versatile method to subclone PCR products directionally into a specific site of virtually any plasmid vector. The procedure requires only four primers, does not require DNA ligase, and may be accomplished in a single day. Ligase-free subcloning is performed by incorporating into the PCR primers sequences at the 5' ends that result in PCR products whose 3' ends are complementary to the 3' ends of the recipient linearized plasmid. The PCR product and the linearized plasmid are spliced together in a second PCR reaction in which Taq polymerase extends the complementary overlapping 3' ends (ligation by overlap extension). Denaturation followed by heterologous reannealing and cyclization results in a cyclic recombinant plasmid with two nicks that may be used directly to transform competent Escherichia coli. In our hands, ligase-free subcloning is rapid, and offers many advantages over existing strategies.

Use of crossover trials to obtain antihypertensive dose-response curves and to study combination therapy during the development of benazepril

When a new drug is developed, one of the first requirements is to establish the correct dose. Unfortunately, in dose-determination studies, not enough lessons have been learned from the past. Pilot studies are often planned without sufficient statistical power, due to an insufficient number of patients and highly variable blood pressure measurements. In the development of the new angiotensin converting enzyme (ACE) inhibitor benazepril, crossover trials were used to obtain useful information. At the end of phase II of the benazepril development, a double-blind crossover study was carried out with 25 patients, and the results made it possible to redefine the 12- and 24-h effects of benazepril in comparison with placebo. Moreover, the crossover trial allowed an investigation of the biological effects of the treatment. In further work, the efficacy of 10 mg benazepril, administered once a day, was confirmed in comparison with captopril and enalapril, with a beta-risk of less than 20%. Since this crossover study yielded reliable data, and there was no carryover effect, a similar crossover design was used to study the interaction between benazepril and nifedipine. In the past, mistakes were made and many antihypertensive drugs were administered in high doses, with no further beneficial effect on blood pressure and an increased risk of side effects. Work described in this paper shows that fewer but better designed and implemented studies can improve the efficiency and value of dose-finding studies for antihypertensive drugs.

Insulin receptors in developing rat liver. Receptor autophosphorylation and phosphorylation of the endogenous substrate pp120/HA4 (ecto-ATPase) in fetal and neonatal liver

The development of insulin receptors and insulin-stimulated receptor autophosphorylation were studied in livers of prenatal and neonatal rats. Insulin receptors were present in mid-gestation, as early as day 14 in fetal development (full term is 22 days in the rat), with ligand-activated receptor kinase present. In contrast, insulin-stimulated phosphorylation of a Mr 120 kd glycoprotein derived from rat liver membranes, known as pp120/HA4 and more recently identified as ecto-ATPase, was not observed in fetal liver until day 17 of gestation. Thereafter, phosphorylation of pp120/HA4 increased throughout late gestation. The data suggest that maturation of the insulin receptor kinase occurs soon after initial appearance of the receptor in mid-gestation, but insulin-stimulated phosphorylation of endogenous substrate(s) is dependent on the appearance of specific substrates, such as pp120/HA4.

[Effect of riboflavin (vitamin B2) on spontaneous gonarthrosis in the mouse]

Male mice of the C57 black strain were given 1 mg/kg body weight of riboflavin (vitamin B2) in their drinking water daily for 4 months, in addition to the vitamin B2 contained in their standard pellet feed. Controls received the standard feed only. Histological examination of the joints at the end of the experiment showed that the incidence of gonarthrosis in the group given supplementary riboflavin was less than half that found in the controls; the number of mice with bilateral gonarthrosis was also considerably smaller, and the severity of the lesions less marked. Signs of physiological degeneration in the epiphyseal cartilage of the femoral and tibial condyles were only marginally less pronounced than in the controls. The notable inhibitory effect of riboflavin, which is known to promote regenerative processes, on osteoarthritis was compared with that of drugs stimulating wound healing, e.g. flavonoids, tribenoside, and zinc sulfate. These latter substances were also found to exert a similar inhibitory effect on spontaneous gonarthrosis in the mouse.

[Campylobacter pylori, gastritis and ulcer disease. Microbiological, histological and serological studies]

In a prospective study of 70 patients with epigastric pain, gastroduodenoscopy revealed gastric and/or duodenal ulcers in a total of 41 and no ulceration in the remainder. Biopsies were taken to assess the severity of gastritis and the presence of Campylobacter pylori (CP) by histology and culture. Gastritis was found in 54 patients. CP was detected in 78% of the ulcer patients and 52% of the patients without ulcer (p less than 0.05). CP was demonstrated in 83% of the histologically diagnosed cases of gastritis (all grades) but no CP was detectable in patients with normal gastric mucosa. Among the ulcer patients, CP was more frequent in those with no history of medication with nonsteroidal antiinflammatory drugs (p less than 0.01). Sera from CP-positive ulcer and gastritis patients have significantly higher levels of IgG antibodies to CP than sera from those found to be free of ulcer or gastritis. In 200 blood donors an increasing percentage of elevated CP-antibody titres were found with advancing age (50% over 60 years of age). Quantification of circulating CP antibodies, would thus seem a valuable adjunct in the diagnosis of gastritis and probably also of peptic ulcer. The data presented furnish further evidence of the high rate of association of CP and the gastritis-peptic ulcer complex.

Glycogen metabolism in neonatal liver of the rat

Prior to birth the fetus of the rat accumulates large quantities of hepatic glycogen, with these stores mobilized as glucose in the early postnatal period to sustain the newborn until the onset of suckling and gluconeogenesis. The liver acts to mobilize glycogen in the early neonatal period and gradually adjusts to the alternating supply of nutrients that results from the onset of a feeding cycle. Early postnatal glycogen mobilization is reflected in the decreased active form of glycogen synthase (GS), the rate-limiting enzyme of glycogenesis, and increased activation of glycogen phosphorylase (GP), the rate-limiting enzyme of glycogenolysis. Levels of smooth endoplasmic reticulum (SER)-associated synthase phosphatase and phosphorylase phosphatase activities are diminished from high prenatal levels, contributing to these changes in activation of GS and GP. With the onset of suckling at 1-4 h after birth the liver again accumulates small quantities of glycogen. The period of 6 to 12 h after birth is characterized by large scale glycogenolysis. Glycogen levels are again increased at 24 h after birth, reflecting hepatic adaptation to the onset of meal feeding.