Autophosphorylating protein kinase 500 is a serine protein kinase expressed progressively with the steps of cellular transformation, approaching levels from 50- to 100-fold in the terminal stages of malignancy. The enzyme possesses a sharply restricted range of substrates: itself and a ribosomal protein with a molecular weight of 31,000 (S6). We report here on the characterization of a monoclonal antibody directed against the autophosphorylation domain of AUT-PK 500. The specificity of the antibody is evidenced by blockage of the enzyme phosphorylation without interfering with the native S6 or synthetic octapeptide (S6-1) serine residue phosphorylations. This represents an important step in identifying a probe that can be used to explore the structure and potential function of AUT-PK 500 in cellular transformation.
Suppression of delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-OHD) and glucose-6-phosphate dehydrogenase (G-6-PD) activities were observed in the rat ovarian tissues following treatment with Mitomycin C (MC), an antibiotic which depresses DNA synthesis. The same treatment also resulted in accumulation of cholesterol and ascorbic acid in the ovaries and a decrease of uterine weight. The atretic changes in the treated ovaries were judged from the activity of the lysosomal enzyme leucine amino-peptidase (LAP). The results suggest a diminution in ovarian steroid biogenesis following an alteration of DNA synthesis.
Context: Preparation of the root canal system is recognized as being one of the most important stages in root canal treatment which removes organic debris and microorganisms from the root canal system by means of chemicomechanical preparation and irrigation of the canals. The use of nickel-titanium instruments has drastically reduced the time and the difficulties that were encountered with traditional hand instruments made up of stainless steel. Utilizing properties of super-elasticity, shape memory and different tapers of these instruments reduces not only the possibility of canal transportation but also affects both the geometry and volume of root canals. This subjects the root dentin to stress and consequently dentinal defects which increases the risk of root fracture during or after root canal treatment. Clinicians now have the opportunity to choose from differently tapered instruments having unique characteristics in their geometry and metallurgy. These are progressively tapered instruments, fixed tapered instruments, and variable tapered instruments, which come with the benefit of conforming to the root canal anatomy as well as removing dentin as little as possible while cleaning and shaping. The aim of this study was to examine the influence o Aim: f instrument taper on the fracture resistance of endodontically treated roots under in vitro experimental conditions.Conclusion: Under the limitations of this study in in-vitro conditions there were no significant differences between the fracture loads between the different file systems used, however samples prepared with Hyflex EDM recorded the highest fracture resistance, followed by ProTaper NEXT, ProTaper Gold and NeoEndo Flex respectively.
We undertook this study to determine the quality, quantity, and temporal relationship of pep M5-induced cytokine release. The ability of pep M5 to stimulate interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) production by a T-cell-depleted, monocyte- and B-cell-enriched cell population was dependent on the presence of T cells. The requirement for T cells could be met by addition of exogenous gamma interferon (IFN-gamma). In the presence of IFN-gamma, pep M5 induced the release of TNF-alpha, IL-1, and IL-6, TNF-alpha levels peaked at 24 h, while IL-1 and IL-6 levels peaked at 48 h. pep M5 induced T cells to produce IFN-gamma, which may have accounted for the ability of the super antigen to induce the production of IL-1, IL-6, TNF-alpha, and TNF-beta by peripheral blood mononuclear cells (PBMC). The addition of excess IFN-gamma to cultures of pep M5 and PBMC did not further increase the release of these cytokines at 24 and 48 h but resulted in sustained higher levels at 72 h. Interestingly, TNF-beta production occurred only in the presence of pep M5 and exogenous IFN-gamma. The ability of pep M5 to induce cytokine production was compared with that of a potent super antigen, staphylococcal enterotoxin B (SEB). SEB was a 2- to 14-fold-more-potent inducer of IFN-gamma production. Furthermore, the profile of cytokine released by PBMC in response to this super antigen mimicked that seen with pep M5 in the presence of exogenous IFN-gamma. In conclusion, pep M5 induces the production of cytokines that are involved in immune regulation and inflammation. These cytokines also play a major role in human T-cell responses to this super antigen.
The kinetics of meiosis and spermiogenesis in Ascaris lumbricoides in vitro was studied by keeping 12 mature males in nutrient medium. The spermatocytes were made radioactive by supplementing the medium with 3H-thymidine for 2 h, following which they were transferred to fresh medium without 3H-TdR. The nematodes were then killed for preparing histological and squash preparations of the testis. An analysis of the migration of "hot" spermatocytes till the formation of mature spermatozoa, in Kodak AR-10 autoradiograms, suggested that the duration of meiosis and spermiogenesis was a little more than 5.5 and 7.6 days, respectively. The total duration of these two events was about 13.1 days when radioactive spermatozoa were detected for the first time.
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