Activation of c-Ki-ras by point mutation within exon 1 was studied in 33 specimens of dysplastic gastrointestinal lesions or of cancers presumed to arise from dysplasia. Samples were obtained from ...patients with underlying ulcerative colitis or Barrett's esophagus, two diseases associated with dysplasia and increased rates of colonic or esophageal adenocarcinoma, respectively. Genomic DNA was amplified using primers bounding this exon in the polymerase chain reaction. Polymerase chain reaction products were analyzed by direct dideoxy sequencing. Three point mutations in codon 13 of c-Ki-ras were found, all in colonic specimens (two high-grade dysplasias and one adenocarcinoma arising in ulcerative colitis). No point mutations were observed in the second exon of c-Ki-ras or in and around codons 12, 13, and 61 of c-N-ras and C-Ha-ras in a partial sampling of the specimens. These data indicate that ras family protooncogene activation is an uncommon event at this level of malignant progression in these disease states. Carcinogenesis in ulcerative colitis and Barrett's esophagus may proceed via different pathways than in sporadic colon cancer, perhaps involving loss or inactivation of suppressor genes.
AVR based Fire Fighting Robot Kadam Supriya Sunil; Mane Pratima Shrikant; Mali Dipali Appasaheb ...
International journal of engineering research & technology (Ahmedabad),
03/2015, Volume:
4, Issue:
3
Journal Article
Fibrinogen Baltimore I is one of the very first congenital abnormal fibrinogens reported over several decades ago; however, the molecular defect of this dysfibrinogen has eluded identification. In ...fact, several reports misidentified the functional defect of Baltimore I, which has impaired fibrin monomer polymerization. Reversed-phase high-performance liquid chromatography analysis of lysyl endopeptidase digest of the purified Baltimore I γ-chain showed an abnormal peptide not found in the co-existing normal γ-chain of this heterozygote. Amino acid sequencing of this peptide indicated that γ-chain Gly292 is replaced by valine. This observation was confirmed, and the genetic defect was determined by direct nucleotide sequencing of a polymerase chain reaction product containing codon γ292, which is mutated: GGC → GTC. The molecular defect of Fibrinogen Baltimore I lies in a region of the γ-chain required for fibrin polymerization, suggesting that the integrity of γGly292 is critical for fibrin assembly.
RAS protooncogene activation has been repeatedly demonstrated in neoplastic cell DNA from patients with AML. Despite the convincing demonstration that activating RAS gene point mutations are critical ...in model systems, their precise prevalence and importance in human cancers such as AML remain speculative. The technology for identifying RAS mutations has changed considerably in recent years. We examined a prospective cohort of 43 acute myeloid leukemia (AML) patients admitted to the University of Maryland Cancer Center for first and second exon mutations of NRAS and KRAS using PCR and DNA sequence analysis. Six (14%) 1st exon NRAS mutations were identified. No clinical or biologic parameter has yet been observed to segregate with RAS activation, although a larger study may be needed to demonstrate this.
In the process of developing accurate quantitation of the ras protein (p21), we have screened available anti-ras antibodies for their utility in immunoprecipitation. Immunoprecipitation with the ...anti-ras antibody RAP-5 consistently failed to precipitate p21 present in two different cell lines (HSIC-5 and MCF-7), but did precipitate numerous other proteins present in these cell lines. Specificity in immunoprecipitation could not be achieved by varying the concentration of RAP-5. In addition, immunohistochemical staining of the nuclei of occasional polymorphonuclear leukocytes is seen, further supporting the contention that RAP-5 is binding to proteins other than ras p21. We conclude that while RAP-5 may recognize an epitope present on the ras protein, this epitope also appears to be present on a wide variety of other cellular proteins and, as such, RAP-5 is of no use in the immunoprecipitation of p21.
Activation of ras protooncogenes by any of several possible mutations in codons 12, 13 or 61 has been demonstrated in a variety of human malignancies, including acute non-lymphoblastic leukemia ...(ANLL). In situ staining for the ras gene product, p21, has been demonstrated in carcinomas of several sites. High levels of p21 expression have been associated with histologic anaplasia in prostate cancer and regional lymph node metastasis in breast cancer. We examined 16 marrow aspirates and blood smears from patients with acute leukemia, predominantly ANLL, and eight controls. Marrow aspirates or blood were smeared on glass slides and fixed immediately in 10% buffered formalin. p21 was examined with avidin-biotin linked immunoperoxidase visualization. Particular attention must be paid to antibody selection and fixation protocol to demonstrate p21, owing to its rapid degradation ex vivo. Three of 16 patients exhibited occasional high p21 expression primarily in leukemic blasts, but in no case were more than 10% of blast cells positive. Normal reticuloendothelial and myeloid cells occasionally exhibited mild to moderately heavy staining, but megakaryocytes, erythroid precursors, lymphocytes and plasma cells were consistently negative. Most patients, 5 normal volunteers and 3 patients with non-malignant disease, exhibited no reactivity, or only a faint blush. These data suggest that while point mutation and concomitant activation of c-N-ras occurs regularly in ANLL, high levels of ras p21 expression are rarely found with this technique.
Poly (l-lactide) (PLLA) is one of the most attractive polymers for use in biomedical applications. In such applications it is necessary to reduce the use of toxic chemicals and catalysts used in PLLA ...synthesis, to minimize any adverse effects. In view of this, we have performed ring opening polymerization (ROP) of l-lactide (LA) using biocompatible initiator, namely, Zinc l-Proline (ZnP) in bulk. High molecular weight PLLA (Mw up to 1.45 × 105 Da) was obtained using the ZnP complex. The ZnP complex is safe, easy to prepare, store and handle. 1H and 13C NMR spectra of PLLA were used to determine the extent of monomer conversion and stereo sequence respectively. Differential Scanning Calorimetry (DSC) and Size Exclusion Chromatography (SEC) were used to determine thermal properties, Mn, Mw and polydispersity index respectively. The mechanism of ROP of LA in the presence of ZnP was studied using Density Functional Theory (DFT) which was in good agreement with results from 1H NMR and Matrix-Assisted Laser Desorption/Ionization Spectrometry (MALDI-TOF). Biocompatibility/non toxicity of PLLA prepared using ZnP was studied in-vitro using MTT assay by examining the proliferation rate of mouse myoblast C2C12 cell line. Escherichia coli and Staphylococcus aureus were used for the study of antibacterial activity of PLLA.
Display omitted
•High molecular weight PLLA was prepared using biocompatible initiator through green route.•The ROP mechanism initiated by zinc proline was studied using computational modeling, 1H-NMR and MALDI-TOF.•In-vitro assay was carried out to check biocompatibility and non toxicity of PLLA.
The following research focuses on the use of machine learning-based beamforming algorithms to improve Massive Multiple Input Multiple Output (MIMO) systems in 5G networks. Four unique algorithms ...namely, the Deep Learning Beamforming Algorithm (DLBA), Reinforcement Learning-Based Doa Estimation Algorithm (RLBEA), Clustering based beam forming algorithm(CBA) and GeneticAlgorithm Based Beam Forming Algoeithm were developed after which each of them was undertook evaluation. Widespread trials, in a simulated 5G environment, have revealed that the DLBA and RLBA considerably outperform other technologies by means of system throughput SINR as well Both the DLBA and RLBA achieved high system throughput, increased SINR levels and low BER. CBA and GABA, using clustering and genetic algorithms as their approaches, displayed moderate values on all assessed composite measures. This research offers important insights on the adaptability and learning potential of machine-learning based beamforming algorithms highlighting their ability to improve efficiency in wireless communication networks during the 5G revolution.
PDF
