718 research outputs found

    Design and analysis report for the RL10-2B breadboard low thrust engine

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    The breadboard low thrust RL10-2B engine is described. A summary of the analysis and design effort to define the multimode thrust concept applicable to the requirements for the upper stage vehicles is provided. Baseline requirements were established for operation of the RL10-2B engine under the following conditions: (1) tank head idle at low propellant tank pressures without vehicle propellant conditioning or settling thrust; (2) pumped idle at a ten percent thrust level for low G deployment and/or vehicle tank pressurization; and (3) full thrust (15,000 lb.). Several variations of the engine configuration were investigated and results of the analyses are included

    PLAGL1 protein is differentially expressed in the nephron segments and collecting ducts in human kidney

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    Introduction. PLAGL1 (pleiomorphic adenoma gene-like 1) is a C2H2-type zinc finger transcription factor associated with the regulation of cell growth and development. Although PLAGL1 expression in kidney was assessed by biochemical methods, the exact localization of the PLAGL1 protein in human kidney has not yet been described. Material and methods. Macroscopically unchanged specimens of kidney tissue were collected from 39 patients undergoing nephrectomy due to renal cell carcinoma. H & E staining of paraffin sections was used to assess histology of the kidney whereas immunohistochemistry was used to localize PLAGL1 protein in kidney compartments. In addition, database sequences search for putative PLAGL1 binding sites among the kidney-related genes was performed. Results. PLAGL1 staining intensity differed depending on the kidney compartment. Strong PLAGL1 immunoreactivity was found in thick ascending limbs of Henle’s loop, distal tubules and collecting ducts, whereas PLAGL1 expression in proximal tubules and renal corpuscles (including podocytes) was moderate and weak, respectively. By the in sillico screening of promoter sequences for PLAGL1 specific DNA-binding sites GGG­GCCCC we designated 43 candidate genes for PLAGL1-regulated genes. Analysis of their functional annotations identified three significantly over-represented gene sets: inositol phosphate metabolic processes (GO), endocrine and other factor-regulated calcium reabsorption (KEGG) and calcium signaling pathways (KEGG). Conclusion. Differences in the renal expression of PLAGL1 suggest that this protein may be involved in the regulation of several cellular pathways both as transcriptional factor and coactivator/corepressor of other tran­scription factors reflecting its role in the cell type-specific control of gene expression.

    Immunohistochemical visualization of pro-inflammatory cytokines and enzymes in ovarian tumors

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    Epithelial ovarian cancer represents one of the most deadly gynaecological neoplasms in developed countries and is a highly heterogeneous disease. Epidemiological studies show that anti-inflammatory drugs reduce the incidence and mortality of several types of cancer, indicating the potential role of pro-inflammatory factors in carcinogenesis. The expression of pro-inflammatory factors in various cancer types, including ovarian cancer, was assessed in many studies, yielding in consistent results, often due to the histological heterogeneity of various cancers. The aim of the study was to investigate the expression of IL-1, IL-6, TGF-β, TNF-α, COX-2,iNOS, and NF-kB in serous and mucinous ovarian cancers. Ninety cases of ovarian tumors classified into mucous and serous type (45 patients in each group) were selected. Each group was classified into subgroups according to the three stages of tumor differentiation, i.e. into (i) benign, (ii) borderline and (iii) malignant tumors. The presence of proteins of interest in paraffin sections was analysed by immunohistochemistry. The expression of most of the studied factors depended on the histological tumor subtype and the degree of malignancy. Expression of NF-κB appears to be related to the level of the neoplastic differentiation only in the group of serous tumors, while the presence of IL-6 in the mucinous tumor subtype was observed only in the case of benign lesions. Expression of IL-1, TNF-α and COX-2 increased with the stage of the disease in both serous and mucinous tumors. The highest level of TGF-β expression was observed in serous borderline tumors. The different levels of iNOS immunoreactivity between the groups of serous and mucinous tumors were observed only in borderline tumors. The results of our study may be helpful in designing therapeutic strategies depending on the type of ovarian cancer

    Underexpression of LATS1 TSG in colorectal cancer is associated with promoter hypermethylation

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    AIM: To investigate large tumor suppressor 1 (LATS1) expression, promoter hypermethylation, and microsatellite instability in colorectal cancer (CRC). METHODS: RNA was isolated from tumor tissue of 142 CRC patients and 40 colon mucosal biopsies of healthy controls. After reverse transcription, quantitative polymerase chain reaction (PCR) was performed, and LATS1 expression was normalized to expression of the ACTB and RPL32 housekeeping genes. To analyze hypermethylation, genomic DNA was isolated from 44 tumor CRC biopsies, and methylation-specific PCR was performed. Microsatellite instability (MSI) status was checked with PCR using BAT26, BAT25, and BAT40 markers in the genomic DNA of 84 CRC patients, followed by denaturing gel electrophoresis. RESULTS: Decreased LATS1 expression was found in 127/142 (89.4%) CRC cases with the average ratio of the LATS1 level 10.33 ± 32.64 in CRC patients vs 32.85 ± 33.56 in healthy controls. The lowest expression was found in Dukes’ B stage tumors and G1 (well-differentiated) cells. Hypermethylation of the LATS1 promoter was present in 25/44 (57%) CRC cases analyzed. LATS1 promoter hypermethylation was strongly associated with decreased gene expression; methylated cases showed 162× lower expression of LATS1 than unmethylated cases. Although high-grade MSI (mutation in all three markers) was found in 14/84 (17%) cases and low-grade MSI (mutation in 1-2 markers) was found in 30/84 (36%) cases, we found no association with LATS1 expression. CONCLUSION: Decreased expression of LATS1 in CRC was associated with promoter hypermethylation, but not MSI status. Such reduced expression may promote progression of CRC

    EQIP\u27s First Year: A Step Closer to Higher Quality in Surgical Education.

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    OBJECTIVE: To describe the first year of the Educational Quality Improvement Program (EQIP) DESIGN: The Educational Quality Improvement Program (EQIP) was formed by the Association of Program Directors in Surgery (APDS) in 2018 as a continuous educational quality improvement program. Over 18 months, thirteen discrete goals for the establishment of EQIP were refined and executed through a collaborative effort involving leaders in surgical education. Alpha and beta pilots were conducted to refine the data queries and collection processes. A highly-secure, doubly-deidentified database was created for the ingestion of resident and program data. SETTING & PARTICIPANTS: 36 surgical training programs with 1264 trainees and 1500 faculty members were included in the dataset. 51,516 ERAS applications to programs were also included. Uni- and multi-variable analysis was then conducted. RESULTS: EQIP was successfully deployed within the timeline described in 2020. Data from the ACGME, ABS, and ERAS were merged with manually entered data by programs and successfully ingested into the EQIP database. Interactive dashboards have been constructed for use by programs to compare to the national cohort. Risk-adjusted multivariable analysis suggests that increased time in a technical skills lab was associated with increased success on the ABS\u27s Qualifying Examination, alone. Increased time in a technical skills lab and the presence of a formal teaching curriculum were associated with increased success on both the ABS\u27s Qualifying and Certifying Examination. Program type may be of some consequence in predicting success on the Qualifying Examination. CONCLUSIONS: The APDS has proved the concept that a highly secure database for the purpose of continuous risk-adjusted quality improvement in surgical education can be successfully deployed. EQIP will continue to improve and hopes to include an increasing number of programs as the barriers to participation are overcome

    First-In-Human Study in Cancer Patients Establishing the Feasibility of Oxygen Measurements in Tumors Using Electron Paramagnetic Resonance With the OxyChip

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    Objective: The overall objective of this clinical study was to validate an implantable oxygen sensor, called the ‘OxyChip’, as a clinically feasible technology that would allow individualized tumor-oxygen assessments in cancer patients prior to and during hypoxia-modification interventions such as hyperoxygen breathing. Methods: Patients with any solid tumor at ≤3-cm depth from the skin-surface scheduled to undergo surgical resection (with or without neoadjuvant therapy) were considered eligible for the study. The OxyChip was implanted in the tumor and subsequently removed during standard-of-care surgery. Partial pressure of oxygen (pO2) at the implant location was assessed using electron paramagnetic resonance (EPR) oximetry. Results: Twenty-three cancer patients underwent OxyChip implantation in their tumors. Six patients received neoadjuvant therapy while the OxyChip was implanted. Median implant duration was 30 days (range 4–128 days). Forty-five successful oxygen measurements were made in 15 patients. Baseline pO2 values were variable with overall median 15.7 mmHg (range 0.6–73.1 mmHg); 33% of the values were below 10 mmHg. After hyperoxygenation, the overall median pO2 was 31.8 mmHg (range 1.5–144.6 mmHg). In 83% of the measurements, there was a statistically significant (p ≤ 0.05) response to hyperoxygenation. Conclusions: Measurement of baseline pO2 and response to hyperoxygenation using EPR oximetry with the OxyChip is clinically feasible in a variety of tumor types. Tumor oxygen at baseline differed significantly among patients. Although most tumors responded to a hyperoxygenation intervention, some were non-responders. These data demonstrated the need for individualized assessment of tumor oxygenation in the context of planned hyperoxygenation interventions to optimize clinical outcomes

    Mapping quantitative trait loci (QTL) in sheep. I. A new male framework linkage map and QTL for growth rate and body weight

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    A male sheep linkage map comprising 191 microsatellites was generated from a single family of 510 Awassi-Merino backcross progeny. Except for ovine chromosomes 1, 2, 10 and 17, all other chromosomes yielded a LOD score difference greater than 3.0 between the best and second-best map order. The map is on average 11% longer than the Sheep Linkage Map v4.7 male-specific map. This map was employed in quantitative trait loci (QTL) analyses on body-weight and growth-rate traits between birth and 98 weeks of age. A custom maximum likelihood program was developed to map QTL in half-sib families for non-inbred strains (QTL-MLE) and is freely available on request. The new analysis package offers the advantage of enabling QTL × fixed effect interactions to be included in the model. Fifty-four putative QTL were identified on nine chromosomes. Significant QTL with sex-specific effects (i.e. QTL × sex interaction) in the range of 0.4 to 0.7 SD were found on ovine chromosomes 1, 3, 6, 11, 21, 23, 24 and 26

    Frequent, Geographically Structured Heteroplasmy in the Mitochondria of a Flowering Plant, Ribwort Plantain (Plantago lanceolata)

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    Recent research has convincingly documented cases of mitochondrial heteroplasmy in a small set of wild and cultivated plant species. Heteroplasmy is suspected to be common in flowering plants and investigations of additional taxa may help understand the mechanisms generating heteroplasmy as well as its effects on plant phenotypes. The role of mitochondrial heteroplasmy is of particular interest in plants as cytoplasmic male sterility is controlled by mitochondrial genotypes, sometimes leading to co-occurring female and hermaphroditic individuals (gynodioecy). Paternal leakage may be important in the evolution of mating systems in such populations. We conducted a genetic survey of the gynodioecious plant Plantago lanceolata, in which heteroplasmy has not previously been reported, and estimated the frequencies of mitochondrial genotypes and heteroplasmy. Sanger sequence genotyping of 179 individuals from 15 European populations for two polymorphic mitochondrial loci, atp6 and rps12, identified 15 heteroplasmic individuals. These were distributed among 6 of the 10 populations that had polymorphisms in the target loci and represented 8% of all sampled individuals and 15% of the individuals in those 6 populations. The incidence was highest in Northern England and Scotland. Our results are consistent with geographic differences in the incidence of paternal leakage and/or the rates of nuclear restoration of male fertility

    Classification and evolutionary history of the single-strand annealing proteins, RecT, Redβ, ERF and RAD52

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    BACKGROUND: The DNA single-strand annealing proteins (SSAPs), such as RecT, Redβ, ERF and Rad52, function in RecA-dependent and RecA-independent DNA recombination pathways. Recently, they have been shown to form similar helical quaternary superstructures. However, despite the functional similarities between these diverse SSAPs, their actual evolutionary affinities are poorly understood. RESULTS: Using sensitive computational sequence analysis, we show that the RecT and Redβ proteins, along with several other bacterial proteins, form a distinct superfamily. The ERF and Rad52 families show no direct evolutionary relationship to these proteins and define novel superfamilies of their own. We identify several previously unknown members of each of these superfamilies and also report, for the first time, bacterial and viral homologs of Rad52. Additionally, we predict the presence of aberrant HhH modules in RAD52 that are likely to be involved in DNA-binding. Using the contextual information obtained from the analysis of gene neighborhoods, we provide evidence of the interaction of the bacterial members of each of these SSAP superfamilies with a similar set of DNA repair/recombination protein. These include different nucleases or Holliday junction resolvases, the ABC ATPase SbcC and the single-strand-binding protein. We also present evidence of independent assembly of some of the predicted operons encoding SSAPs and in situ displacement of functionally similar genes. CONCLUSIONS: There are three evolutionarily distinct superfamilies of SSAPs, namely the RecT/Redβ, ERF, and RAD52, that have different sequence conservation patterns and predicted folds. All these SSAPs appear to be primarily of bacteriophage origin and have been acquired by numerous phylogenetically distant cellular genomes. They generally occur in predicted operons encoding one or more of a set of conserved DNA recombination proteins that appear to be the principal functional partners of the SSAPs
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