PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Processing factor”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1992

The manufacturing process of recombinant factor VIII, recombinate.

In summary, this brief report documents the cell culture and rAHF purification systems used to produce rFVIII and has focused on the unique characteristics of the cell line, the production process, and purification system used. This review emphasizes the general philosophy used throughout the research and development of this innovative and complex therapeutic agent, in order to provide a safe and efficacious rAHF in the management of individuals with hemophilia A. This review provides a brief description of the in-process system and controls that have been incorporated to meet the high standards and safety objective.

Animals↗
PubMed1977

Comparison of the cross-linking patterns of lamprey fibrinogen and fibrin by the action of the intrinsic lamprey factor XIII and human factor XIII during the process of blood coagulation.

Intrinsic lamprey factor XIII cross-links the gamma chain of lamprey fibrin (50,000 daltons) to the gamma-dimer (100,000 daltons). The alpha-chain (110,000 daltons) is cross-linked very slowly to alpha-dimer (210,000 daltons) and alpha-trimer (330,000 daltons). In contrast, human factor XIII, when added in combination with intrinsic lamprey factor XIII, cross-links the alpha-chain of lamprey fibrin to a high molecular weight polymer, and any remaining gamma-chain is also cross-linked to a polymer. However, the gamma-chain that has previously cross-linked to the gamma-dimer by the intrinsic lamprey factor XIII remains as a gamma-dimer. Factor XIII-free lamprey fibrin cross-links all its subunits (alpha, beta, gamma) to high molecular weight polymers when human factor XIII is added. In contrast to human and bovine fibrin where alpha-chain cross-linking in the process of blood coagulation commences when all of the gamma-chain has cross-linked, the lamprey alpha-chain will begin to cross-link when approximately half of the gamma-chain has cross-linked to the gamma-dimer.

Animals↗
PubMed1987

Disruption of intracellular processing of epidermal growth factor by methylamine inhibits epidermal growth factor-induced DNA synthesis but not early morphological or transcriptional events.

Upon internalization, epidermal growth factor (EGF) is proteolytically processed from its COOH terminus as it traverses intracellular vesicles and lysosomes. This report describes experiments which were conducted to determine whether lysosomotropic amines such as methylamine, which are known to inhibit degradation of EGF, are able to significantly inhibit the COOH-terminal processing of EGF, and whether disruption of EGF processing would negatively affect EGF-stimulated events such as DNA synthesis and induction of specific mRNA species. The results of these experiments indicated that, whereas methylamine treatment had no effect on EGF binding or internalization, vesicular translocation from endocytic vesicles to lysosomes was halted and processing of EGF was severely inhibited. The stimulation of DNA synthesis beginning 12 h after EGF exposure was also markedly inhibited by methylamine treatment. However, addition of methylamine alone produced a non-specific inhibition of DNA synthesis. The ability of EGF to induce specific transcription of the rat transin gene within 6 h of treatment was also not inhibited by methylamine treatment, but was actually increased in the presence of methylamine. These results suggest that at least some early transcriptionally regulated events induced by EGF do not require vesicular processing of EGF (or its receptor) and that the signal transduced by the binding of EGF to its receptor occurs in, or proximal to, the endocytic vesicles.

Animals↗
PubMed1978

The isolation and characterization of elongation factor eEF-Ts from Krebs-II mouse-ascites-tumor cells and its role in the elongation process.

A factor having activity similar to that described in other systems for the eukaryotic elongation factor eEF-Ts was isolated from the heavy, aggregate form of eEF-TH (formally named EF-1H). This protein has a molecular weight of 52000 under native conditions and of 25500 under denaturing conditions. It has been shown to stimulate eEF-Tu-dependent aminoacyl-tRNA binding to ribosomes and therefore eEF-Tu/eEF-G-dependent polyphenylalanine synthesis by ribosomes and was found to stimulate GDP-GTP exchange in eEF-Tu . GDP complexes. In the course of this work, it was also demonstrated that the removal of deacylated tRNA from the ribosome is a GTP-dependent process. This report, therefore, adds further support to the concept that a third elongation factor, eEF-Ts, may be common to all systems in the eukaryotic domain.

Animals↗
PubMed1991

Factors affecting the process of color matching restorative materials to natural teeth.

Resin-based restorative materials have to not only function properly but also fulfill esthetic demands; restorations must harmonize in shape and shade with natural teeth. The human perception of color is affected by external factors. The influence of these factors is discussed in regard to two pairs of composite resins: Silux/Valux and Pekalux/Pekafill. With the knowledge of the influence of these factors and with the accuracy of modern color measurement instruments, it is today possible to carry out restorative work to meet the highest esthetic standards.

Color↗
PubMedDate not supplied

[Effect of endogenous factors on the process of gas bubble formation in the body in decompression].

Animal experiments were carried out to study the effects of a feeding regimen and diet composition on the intensity of post-decompression bubble formation as well as to establish a correlation between this process and previous decompression, increased and decreased muscle work, and physico-chemical and morphological blood parameters. There was a correlation between the rate of bubble formation during decompression and the above factors.

Animals↗
PubMed1992

Host factor requirements for processive antitermination of transcription and suppression of pausing by the N protein of bacteriophage lambda.

The N protein of phage lambda prevents termination of transcription by Escherichia coli RNA polymerase at Rho-dependent and -independent terminators in the lambda early operons. The modification of RNA polymerase by N requires an N-utilization (nut) site, present in each lambda early operon, and involves the E. coli factors NusA, NusB, NusG, and ribosomal protein S10. We show that, in the presence of NusA, N inhibits pausing by RNA polymerase and Rho-dependent termination in vitro at three sites in the lambda terminator tR1 which are located less than 100 base pairs downstream from nutR. NusA is also sufficient for partial antitermination at sites located farther downstream from nutL and nutR if there is a high concentration of N in the reaction. At low concentrations of N, the additional factors NusB, S10, and NusG are essential for antitermination at distal sites. In these conditions, the presence of NusA, NusB, S10, and NusG in the reaction enables N-modified RNA polymerase to elongate efficiently and processively through Rho-dependent and -independent terminators over distances as great as 7 kilobases downstream from the lambda nut sites. This substantial processivity of antitermination in vitro also occurs in vivo and probably reflects the stable association of N, NusA, NusB, S10, and NusG with RNA polymerase and nut site RNA in elongation complexes transcribing the lambda chromosome.

Bacterial Proteins↗
PubMed1981

Long-term epidermal growth factor-receptor internalization and processing in quiescent human fibroblasts.

Epidermal growth factor is internalized into cells and concomitantly induces a massive clearance of up to 90% of its total surface receptors. The hormone-receptor complex is delivered to lysosomes and degraded or inactivated. Lysosomotropic alkylamines block the degradation but not the binding or internalization of ligand-receptor complexes and thus their presence results in a marked potentiation of intracellular accumulation of epidermal growth factor. We have used these alkylamines as pharmacological tools to trap internalized 125I-labeled epidermal growth factor and now report that the residual population of epidermal growth factor receptors remaining on human fibroblasts after completion of the receptor clearance process is not only accessible for ligand binding but also directs the continued internalization and degradation of this growth factor over prolonged periods of time. We also show that down regulation of epidermal growth factor receptors does not result in desensitization of cells to the mitogenic response.

Cell Compartmentation↗
PubMed1986

Organization and sequence of the human insulin-like growth factor I gene. Alternative RNA processing produces two insulin-like growth factor I precursor peptides.

Insulin-like growth factor I (IGF-I), a 70-amino acid basic polypeptide, plays a fundamental role in postnatal mammalian growth as a major mediator through which growth hormone exerts its biological effects. We have recently identified two human IGF-I cDNAs which predict distinct peptide precursors of 153 and 195 amino acids. In the present study, both cDNAs were used to isolate and characterize the human IGF-I gene from genomic libraries. The IGF-I gene extends over at least 45 kilobase pairs and contains five exons interrupted by four introns. The DNA sequence of exons 1 through 4 encodes the 195-amino acid precursor, while exons 1, 2, 3, and 5 code for the 153-residue peptide, confirming the hypothesis that at least two IGF-I mRNAs are generated by alternative RNA processing of the primary gene transcript. The structure of the IGF-I gene resembles that of its companion somatomedin, IGF-II, as judged by the analogous location of two introns and considerable nucleotide and amino acid sequence similarity, but appears more distantly related to other members of the insulin gene family. Restriction endonuclease polymorphisms in the IGF-I gene, which map near exon 5 as determined by Southern blot analysis, will be useful in defining the genetics of familial growth failure.

Amino Acid Sequence↗
PubMed1988

Quantitative evaluation of the factors affecting the process of fibroblast-mediated collagen gel contraction by separating the process into three phases.

Kinetics of collagen gel contraction by fibroblasts cultured in vitro was examined in detail for quantitative analysis. The process of collagen gel contraction was not expressed by a simple function of time. It appeared to consist of three distinct phases; a lag phase before the initiation of contraction, a rapid contraction phase and a slow contraction phase. Factors affecting the gel contraction can be classified into four groups. The first group includes increase in cell number, in culture temperature or in serum concentration, which strengthened the contraction in all the three phases, suggesting that they affected cellular activity particularly in interacting with collagen. The second group repressed the later two phases of contraction but not the first lag phase, typically increase in collagen concentration and a low dose of nocodazole or colcemid. Increasing population doubling levels of fibroblasts belongs to the third group which caused a reduced lag time but no change in the later two phases. Cytochalasin D at a low dose (0.03-0.1 microgram/ml) is another example of the third group which shortened the lag time. The last group did not change the contraction curves. Donor age of fibroblasts isolated from the skin is an example of this group. The rate of rapid contraction in the second phase was always found to be closely correlated with the degree of contraction at the end of the third phase, in a whole set of the factors above mentioned. The results suggest that the extent of the later two phases might be a reflection of the same cellular activity, particularly cytokinetical one. The lag time is directly related to the time for cells to become elongate in shape as observed by using the video-microscopy, suggesting that the lag phase is also governed by cytokinetical activity. The two cytokinetical activities are closely related, but may be distinct, since the factors affecting the collagen gel contraction can be differentiated into four groups.

Adult↗
PubMed1992

Situational factors and thought processes associated with unprotected intercourse in heterosexual students.

Heterosexual students were asked to recall two sexual encounters from the preceding six months: one in which they had unprotected intercourse ('unsafe' encounter) and one in which they resisted a strong temptation to have unprotected intercourse ('safe' encounter). The aims were to record justifications for unprotected intercourse that respondents had given themselves during the unsafe encounter and to identify factors that distinguished between the encounters. In respondents recalling an unsafe encounter (n = 284), the most common self-justification reported was that there was no need for concern since measures to avoid pregnancy had been taken. The first factor that emerged from a Factor Analysis of the self-justification data involved using perceptible characteristics to infer that the partner was unlikely to be infected. Among respondents recalling both encounters (n = 173), there was a trend for type of partner to distinguish between the encounters. With this variable controlled (n = 115), desires, knowledge of condom availability, communication about condom use, degree of boredom, and level of intoxication differentiated between the encounters. The results are discussed in relation to those obtained in our earlier study of gay men.

Adolescent↗
PubMed1991

[Proteinases as a pathogenetic factor in inflammatory processes in periodontal tissues].

Collagenolytic activity (CA) in cervical fluid of patients with inflammation of periodontium was increased with increasing activity of the pathological process. Enhanced CA in patients with severe forms of periodontitis is probably due to depletion of endogenous inhibitors and to the transition of the latent collagenase to its active form. Studies of the effect of EDTA, PMSF and PCMB on CA show that proteinases are an essential factor in inflammation of periodontium.

Adolescent↗