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PubMed2004

PKC downstream of Pl3-kinase regulates peroxynitrite formation for Nrf2-mediated GSTA2 induction.

The protective adaptive response to electrophiles and reactive oxygen species is mediated by the induction of phase II detoxifying genes including glutathione S-transferases (GSTs). NF-E2-related factor-2 (Nrf2) phosphorylation by protein kinase C (PKC) is a critical event for its nuclear translocation in response to oxidative stress. Previously, we have shown that peroxynitrite plays a role in activation of Nrf2 and Nrf2 binding to the antioxidant response element (ARE) via the pathway of phosphatidylinositol 3-kinase (Pl3-kinase) and that nitric oxide synthase in hepatocytes is required for GSTA2 induction. In view of the importance of PKC and Pl3-kinase in Nrf2-mediated GST induction, we investigated the role of these kinases in peroxynitrite formation for GSTA2 induction by oxidative stress and determined the relationship between PKC and Pl3-kinase. Although PKC activation by phorbol 12-myristate-13-acetate (PMA) did not increase the extents of constitutive and inducible GSTA2 expression, either PKC depletion by PMA or PKC inhibition by staurosporine significantly inhibited GSTA2 induction by tert-butylhydroquinone (t-BHQ) a prooxidant chemical. Therefore, the basal PKC activity is requisite for GSTA2 induction. 3-Morpholinosydnonimine (SIN-1), which decomposes and yields peroxynitrite, induced GSTA2, which was not inhibited by PKC depletion, but slightly enhanced by PKC activation, suggesting that PKC promotes peroxynitrite formation for Nrf2-mediated GSTA2 induction. Treatment of cells with S-nitroso-N-acetyl-penicillamine (SNAP), an exogenous NO donor, in combination with t-BHQ may produce peroxynitrite. GSTA2 induction by SNAP + t-BHQ was not decreased by PKC depletion, but rather enhanced by PKC activation, showing that the activity of PKC might be required for peroxynitrite formation. LY294002 a Pl3-kinase inhibitor blocked GSTA2 induction by t-BHQ, which was reversed by PMA-induced PKC activation. These results provide evidence that PKC may play a role in formation of peroxynitrite that activates Nrf2 for GSTA2 induction and that PKC may serve an activator for GSTA2 induction downstream of Pl3-kinase.

Animals↗
PubMedDate not supplied

Induction with sevoflurane-remifentanil is comparable to propofol-fentanyl-rocuronium in PONV after laparoscopic surgery.

PURPOSE: To compare sevoflurane-remifentanil induction and propofol-fentanyl-rocuronium induction with regards to the frequency of moderate to severe postoperative nausea and vomiting (PONV) in the first 24 hr after laparoscopic day surgery. METHODS: After informed consent, 156 ASA physical status class I to III patients undergoing laparoscopic cholecystectomy or tubal ligation were randomized to either induction with sevoflurane 8%, N(2)O 67% and iv remifentanil 1 to 1.5 microg.kg(-1) or induction with iv fentanyl 2 to 3 microg.kg(-1), propofol 2 mg.kg(-1), and rocuronium 0.3 to 0.5 mg.kg(-1). All patients received iv ketorolac 0.5 mg.kg(-1) at induction and sevoflurane-N(2)O maintenance anesthesia with rocuronium as needed. PONV was treated with iv ondansetron, droperidol, or dimenhydrinate; postoperative pain was treated with opioid analgesics. Patients were followed for 24 hr with regards to PONV and pain. Intubating conditions, induction and emergence times, time to achieve fast-track discharge criteria, and drug costs were measured. RESULTS: No differences were seen between the two groups in their frequencies of 24-hr moderate to severe PONV and postoperative pain, or in their intubating conditions, induction and emergence times, and time to achieve fast-track discharge criteria. Patients undergoing sevoflurane-remifentanil induction received more morphine (11 mg vs 8 mg; P < 0.001) in the postanesthetic care unit. Sevoflurane-remifentanil induction resulted in similar anesthetic and total drug costs for both procedures. CONCLUSION: We did not demonstrate any difference in PONV, pain, or anesthetic/recovery times or costs between the sevoflurane and propofol groups. Sevoflurane-remifentanil induction is a feasible technique for anesthetic induction.

Adult↗
PubMed2001

Initial clinical experience with interleukin-2 receptor antagonist induction in combination with tacrolimus, mycophenolate mofetil and steroids in simultaneous kidney-pancreas transplantation.

Since 1996, our standard immunosuppressive protocol for simultaneous kidney-pancreas transplantation (SKPT) has been tacrolimus (TAC), mycophenolate mofetil (MMF) and steroids without antibody induction. When basiliximab and daclizumab, monoclonal antibodies directed against the interleukin-2 receptor (IL-2R), became available, we selectively added these agents to our standard protocol. The purpose of this prospective, open-label study was to evaluate the safety and efficacy of IL-2 receptor antagonists in SKPT. From April 1998 to August 1999, 35 SKPTS were performed. One patient with delayed graft function received Thymoglobulin and was excluded; 17 received no induction, and 17 received IL-2R antagonists (9 basiliximab, 8 daclizumab) as induction. Demographic- and transplant characteristics were similar between the two groups. At 6 months, patient survival was 88 % (15/17) in the induction arm compared to 100 % (17/17) in the no-induction arm, P = NS. The 2 causes of death were sepsis and hemolytic uremic syndrome, and both patients died with functioning grafts. Death-censored pancreas and kidney graft survival rates in the induction and the no-induction groups were 88 % vs. 100 % respectively, in both groups. The incidence of acute rejection (kidney or pancreas) at 6 months did not differ between the two groups (35 % in both groups). Biopsy proven pancreas and kidney acute rejections were 35 % vs. 24 % and 12 % vs. 12 % in the induction- and no-induction groups, respectively. The incidences of major infection and readmission did not differ between groups. TAC trough levels and mean daily doses of TAC, MMF and steroids did not differ between the two groups at 1, 3, and 6 months. The incidence of event-free survival (no death, rejection, or graft loss) at 6 months was 59 % (10/17) in the induction and 65 % (11/17) in the no-induction group. Basiliximab and daclizumab appear to be safe in SKPT. However, the preliminary results of this study do not demonstrate a significant benefit in either reducing the incidence of acute rejection or improving outcomes at 6 months. Larger studies with longer follow-up are needed to confirm these findings.

Adrenal Cortex Hormones↗
PubMed2005

Herbivores, vascular pathways, and systemic induction: facts and artifacts.

Over the past 10 years there has been tremendous growth in our understanding of molecular, chemical, and morphological induction of traits involved in the resistance of plants to herbivores. Although it is well established that the patterns of induction can be constrained by a plant's vascular architecture, studies often fail to account for these constraints. Failure to do so has the potential to severely underestimate both the patterns and extent of induction. Here I review (1) the evidence for vascular control of induced responses, (2) how interspecific variation in phyllotaxy influences spatial patterning of induction, (3) the factors, phloem transport and volatile production, that may break down vascular constraints and lead to more widespread induction, and (4) the experimental approaches that could be compromised when vascular architecture is not considered. I show that vascular constraints in systemic induction are commonplace, but vary among species. I suggest that when induction is more widespread than expected from patterns of phyllotaxy, differences in vascular connectivity and volatile production may be responsible. I argue that advances in the mechanisms of systemic induction, cross-talk between different signal transduction pathways, specificity of induction, costs and benefits of systemic induction, and the effects of induced changes on herbivores and their natural enemies require that experiments be designed to examine and/or control for vascular constraints in systemic induction.

Animals↗
PubMed2006

Induction of human UDP-glucuronosyltransferase 1A1 by cortisol-GR.

During the course of the study of UGT1A1 induction by bilirubin, we could not detect the induction of the reporter gene (-3174/+14) of human UGT1A1 in HepG2 by bilirubin (Mol. Biol. Rep. 31: 151-158 (2004)). In this report, we show the finding of the induction of the reporter gene of UGT1A1 by cortisol at 1 microM, a major natural cortico-steroid, with human glucocorticoid receptor (GR). RU486 of a typical GR antagonist at 10 microM inhibited the induction by cortisol from 5.9- to 1.8-fold. This result indicates that the induction by cortisol-GR is dependence on ligand-binding. This induction is caused by the UGT reporter gene itself, from the results of noinduction with control vector pGL2 (equal to pGV-C) in the presence of cortisol-GR. We confirmed that the induction of the reporter gene by cortisol is dependent on the position of proximal element (-97/-53) of UGT1A1. From this result, we concluded that the increase of corticosteroid in neonates must induce the elevation of UGT1A1 after birth and prevent jaundice. With the study of induction by corisol, we studied the influence of co-expression of PXR (pregnenolone xenobiotic receptor) with the UGT1A1 reporter gene and we could not find the induction of UGT1A1 expression in the presence of dexamethasone, rifampicin, or pregnenolone 16alpha-carbonitrile of the PXR ligands. These results suggest that the induction of UGT1A1 expression by GR is not mediated by PXR, unlike the induction of CYP3A4 through PXR.

Base Sequence↗
PubMed2004

Induction concurrent chemoradiation therapy for invading apical non-small cell lung cancer.

OBJECTIVE: Although non-small cell lung cancer (NSCLC) involving the superior sulcus has been generally treated with radiation therapy (RT) followed by surgery, local recurrence is still a big problem to be solved. We investigated a role of induction therapy, especially induction concurrent chemoradiation therapy (CRT), on the surgical results of this type of NSCLC. METHOD: We retrospectively reviewed 30 patients with NSCLC invading the apex of the chest wall who underwent surgery from 1987 to 1996. Ten patients (57 +/- 8 years) received surgery alone, 9 (55 +/- 13 years) received RT (42 +/- 7 Gy) followed by surgery and 11 (51 +/- 9 years) received cisplatin based chemotherapy and RT (47 +/- 5 Gy) as an induction therapy. RESULTS: Two and 4-year survival rates were 30% and 20% in patients with surgery alone, 22% and 11% in patients with induction RT, and 73% and 53% in patients with induction CRT, respectively. The survival was significantly better in patients with induction CRT than those with induction RT or surgery alone. Univariate analysis demonstrated that curability (yes versus no: p = 0.027) and induction therapy (surgery alone and RT versus CRT: p = 0.0173) were significant prognostic factors. Multivariate analysis revealed that only induction therapy (p = 0.0238) was a significant prognostic factor. CONCLUSIONS: Induction CRT seems to improve the survival in patients with NSCLC invading the apex of the chest wall compared with induction RT or surgery alone.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

Treatment of extensive stage small cell bronchogenic carcinoma. Effects of variation in intensity of induction chemotherapy.

Forty-nine consecutive previously untreated patients with extensive stage small cell bronchogenic carcinoma were treated with cyclophosphamide 1,000 mg/m2, doxorubicin 50 mg/m2, etoposide (VP-16-213) 125 mg/m2, and vincristine 1.4 mg/m2 (maximum 2 mg) as induction chemotherapy. Thirty-four patients were given high-intensity therapy, receiving these drugs on both Days 1 and 8 of two or three 21-day induction courses. Fifteen other patients were treated with moderate intensity, receiving these drugs only on Day 1 of two 21-day induction courses. The number and intensity of induction courses were determined by the time of entry into the study. There were 31 complete or partial remissions among the 33 evaluable patients treated with high-intensity therapy (94 percent), including eight complete remissions (24 percent), whereas there were 11 responses (73 percent) including three complete responses (20 percent) among the 15 patients treated with moderate-intensity therapy. There was no marked tendency for the patients in the high-intensity group to have a more favorable response to the induction chemotherapy (p = 0.22), and survival experience was very similar in the two groups (p = 0.92). Overall median survival was 12 months. Within the high-intensity group, there was no significant difference between patients receiving two or three courses of induction therapy with respect to response (p = 0.97) or survival (p = 0.32). There were six induction deaths in the high-intensity induction group (18 percent) and one induction death in the moderate-intensity group (7 percent) (p = 0.59). In addition to the expected hematologic and infectious complications, there were unexpectedly high frequencies of mucositis, reversible congestive heart failure, and severe peripheral neuropathy in patients treated with high-intensity induction. Only two patients, both in the high-intensity group, were alive and free of disease at 24 months. Increasing the intensity of induction chemotherapy with these drugs did not significantly improve response or survival in extensive stage small cell bronchogenic carcinoma.

Adult↗
PubMed1991

Striatal c-fos induction by drugs and stress in neonatally dopamine-depleted rats given nigral transplants: importance of NMDA activation and relevance to sensitization phenomena.

Induction of the proto-oncogene c-fos occurred in cells of the striatum in response to stimuli that are known to release dopamine (DA). As revealed by fos immunocytochemistry, amphetamine (AMPH) produced c-fos induction in many cells of the medial two-thirds of the striatum of normal rats, with patchy labeling in the lateral third. The lateral patches were found to be coincident with patches of striatal neurons lacking calbindin immunoreactivity. In animals DA-depleted at birth, few fos-immunoreactive neurons were present in response to AMPH. In those with unilateral transplants of DA-rich mesencephalic tissue, c-fos induction was greater on the transplanted side. The DA D1 antagonist SCH 23390 completely blocked c-fos induction in all animals. The N-methyl-D-aspartate antagonist MK-801 also blocked c-fos induction by AMPH within the medial striatum, but intensified c-fos induction laterally in those animals with DA innervation. A second set of experiments examined the functional importance of c-fos induction in the AMPH sensitization of turning behavior that occurs in these animals. Both AMPH and stress produced turning, but only AMPH produced widespread c-fos induction, and stress-induced turning only occurred after exposure to AMPH. Treatment with MK-801 prior to AMPH administration blocked the subsequent development of stress-induced turning. Whereas a high dose of MK-801 (1.0 mg/kg) completely blocked c-fos induction, a lower dose (0.1 mg/kg) blocked c-fos induction in controls, but left patches of fos-immunoreactive neurons in lesioned animals given transplants. Thus the sensitization of transplant-related behaviors is NMDA dependent and associated with c-fos induction in host striatal neurons.

Amphetamine↗
PubMed1993

Metrazole induction of c-fos and proenkephalin gene expression in the rat adrenal and hippocampus: pharmacological characterization.

We have previously reported that the administration of metrazole (MTZ) produces a sequential, dose-dependent induction of c-fos and proenkephalin (Penk) gene expression in the rat hippocampus and adrenal. The adrenal is more sensitive to induction of these genes by MTZ. In the present study, we have compared the induction of c-fos and Penk in the hippocampus and adrenal, and examined the consequences of selected pharmacological manipulations. Treatment with LY274614, a competitive NMDA-receptor antagonist, blocked MTZ-induced convulsions and the MTZ-induction of c-fos and PPenk mRNAs in the hippocampus, and PPenk mRNA in the adrenal. However, in the adrenal the MTZ-induction of c-fos was only partially inhibited by LY274614. A combination of peripheral acting cholinergic antagonists (chlorisondamine plus methylatropine) prevented the MTZ-induction of adrenal c-fos and PPenk mRNA without significant alterations in the MTZ-induction of hippocampal c-fos mRNA or convulsions. Trifluoperazine, a calcium/calmodulin inhibitor, attenuated the MTZ-induction of c-fos mRNA while potentiating the MTZ-induction of PPenk mRNA in both the hippocampus and the adrenal. These results demonstrate that the MTZ induction of c-fos and Penk gene expression in the rat adrenal can be modulated by drugs acting in the CNS at NMDA receptors, in the periphery at postsynaptic cholinergic receptors and intracellularly at the calcium/calmodulin signal transduction pathway. Furthermore, we provide additional evidence that MTZ-induction of c-fos and Penk mRNAs can be dissociated by drugs acting at these sites.

Adrenal Glands↗
PubMed2006

Role of cyclic nucleotides in fetal hemoglobin induction in cultured CD34+ cells.

OBJECTIVE: In vivo, several drugs have been shown to increase fetal hemoglobin (HbF), including 5-azacytidine (AZA), sodium butyrate (SB), and hydroxyurea (HU). Studies in K562 cells suggest that cyclic guanosine monophosphate (cGMP) is required for HbF induction; however, the role of cyclic nucleotides in HbF induction in primary erythroid cultures has not been established. METHODS: CD34-selected peripheral blood monocytes cultured in a semi-solid serum-free system that mimics in vivo F-cell production are utilized to explore the role of cyclic adenosine monophosphate (cAMP) and cGMP in HbF induction in response to HU, AZA, and SB. RESULTS: In serum-free CD34 cultures, HU, SB, and AZA all markedly stimulate FNRBC production up to 30-fold, associated with induction of gamma-globin mRNA and total HbF protein. Guanylate cyclase inhibition results in only minimal blunting of HbF induction by each agent. In contrast, adenylate cyclase inhibition markedly reduces HU, SB, and AZA-mediated FNRBC induction and gamma-globin mRNA induction. The adenylate cyclase activator forskolin modestly induces FNRBC production and augments the action of standard induction agents. HU, AZA, and SB, however, fail to significantly stimulate adenylate cyclase themselves. CONCLUSIONS: In human CD34(+) cultures, cAMP production is required for full induction of HbF by HU, SB, and AZA, while perturbation of cGMP production has only minimal effects. These findings are in marked contrast to data in K562 cells where cGMP production is critical for HbF induction while cAMP stimulation blunts HbF response, and suggest that these agents may share a common induction pathway.

Adenylyl Cyclases↗
PubMed2005

Multivariate analysis of antibody induction therapy and their associated outcomes in deceased donor transplants.

AIMS: The aims of this study were to describe factors associated with the use of overall induction, classes of induction agents, and to evaluate the incidence of acute rejection, short-term graft survival, and patient survival. METHODS: Of 24,901 transplants reported to the United Network for Organ Sharing (UNOS) between 1999 and 2001, 51% received induction therapy including Thymoglobulin (T; n = 3090), Simulect (S; n = 6063), or Zenapax (Z; n = 3755). Propensity scores (PS) were calculated to indicate factors associated with use of induction and for each induction agent. Outcome parameters included graft survival (GS), hazard ratio (HR) for graft loss (GL), and odds ratio (OR) for first-year acute rejection (AR). RESULTS: Pediatric (PS = 1.29; 95% confidence interval [CI] 1.12-1.49, vs adults) and retransplanted recipients (PS = 1.36; 1.23-1.49, vs first) were more likely to receive induction. One-year GS (90.1 vs 88.0%; P < .001), GL = 0.92% (0.86-0.98; P = .01), and AR free = 0.74 (P < .001) were superior in patients receiving induction. Using multivariate analysis, the odds of rejection 0.73 (0.68-0.78), GL 0.91 (0.85-0.97), and death 0.90 (0.82-0.98) were lower in those receiving induction. Among patients given induction, those receiving T were more likely sensitized (PS = 1.50%; 1.31-1.71), retransplanted (PS = 1.51; 1.31-1.75), or had delayed graft function (PS = 1.75; 1.58-1.93). T decreased the odds of rejection compared with S or Z (OR = 0.74; 0.69-0.79), but the type of induction agent did not have an impact on graft outcome HR for T = 1.07 (0.96-1.19). CONCLUSIONS: The use of antibody induction was associated with lower risk of rejection and better GS. There were no differences in GS among individual regimens. Comparative safety data were not analyzed but should be taken into consideration when choosing antibody preparations.

Adult↗
PubMed1992

Infusion of propofol to identify smallest effective doses for induction of anaesthesia in young and elderly patients.

We studied 110 patients older than 60 yr or aged 18-50 yr as separate groups in two stages to identify the smallest effective doses of propofol for induction of anaesthesia. In the elderly patients, in stage 1, at infusion rates of 25, 50 or 100 mg min-1 the mean (SD) doses administered were propofol 0.82 (0.14) mg kg-1, 1.22 (0.24) mg kg-1 and 1.65 (0.60) mg kg-1 and the induction times 140.1 (21.9) s, 103.2 (23.5) s and 69.4 (10.0) s, respectively. In stage 2, after induction with a fixed dose of 0.82 mg kg-1 as a bolus over 5 s or as an infusion at 25 mg min-1, the times for induction were 38.5 (14.0) s and 144.5 (36.6) s, respectively. In the young patients, at induction rates of 33.3, 50, 100 or 200 mg min-1, the doses administered were propofol 1.36 (0.28) mg kg-1, 1.46 (0.12) mg kg-1, 1.85 (0.43) mg kg-1 and 2.39 (0.50) mg kg-1 and the induction times 145.0 (25.4) s, 120.0 (18.4) s, 80.2 (19.2) s and 54.5 (10.4) s, respectively. In stage 2, a fixed induction dose of 1.46 mg kg-1 resulted in induction times of 35.0 (8.5) s and 134.0 (26.8) s, respectively. In stage 2 of each age group, induction was achieved with smaller doses than those recommended previously and there was no difference in the number of patients in whom induction of anaesthesia was successful or in the measured cardiorespiratory variables between the two induction regimens. This suggests the latter effects are caused by the dose administered and not the rate of administration.

Adolescent↗
PubMed2004

Two-dose daclizumab induction therapy in 209 liver transplants: a single-center analysis.

BACKGROUND: Patient and graft survival after liver transplantation are adversely affected by early posttransplant renal dysfunction. Therefore, our immunosuppressive strategies should be as "renal sparing" as possible. This is the largest published series to date using daclizumab induction therapy in a renal-sparing regimen. METHODS: This is a retrospective, nonrandomized study comparing 209 adult liver transplants with daclizumab induction to 115 transplants with no induction. RESULTS: Patient and graft survival were similar, despite higher pretransplant acuity of illness and older age in the induction group. Acute rejection within the first 6 months occurred less commonly in the induction group (25.4% vs. 39.1%, P=0.01), despite significantly delayed initiation and lower doses of a calcineurin inhibitor. Mycophenolate mofetil was used more commonly in induction patients, but the efficacy of daclizumab in preventing rejection was independent of this. Patients with a pretransplant creatinine concentration 1.5 mg/dL or less had less rejection if they received induction. Renal function worsened in noninduction patients but showed sustained improvement throughout follow-up in induction patients with a pretransplant creatinine concentration greater than 1.5 mg/dL. Induction therapy provided better rejection prophylaxis among those requiring temporary calcineurin inhibitor cessation because of renal dysfunction. The incidences of histologic hepatitis C recurrence and cytomegalovirus infection were similar in each group. CONCLUSIONS: Liver recipients with and without pretransplant renal dysfunction have less acute rejection with daclizumab induction therapy. This is not associated with an increased risk of over-immunosuppression. Sustained renal improvement in recipients with pretransplant renal dysfunction is possible with daclizumab induction.

Antibodies, Monoclonal↗
PubMed2005

Electromagnetic interference of implantable unipolar cardiac pacemakers by an induction oven.

Induction ovens have been reported to exert electromagnetic interference on implanted cardiac pacemakers. In an attempt to quantitatively investigate the electromagnetic interference caused by an induction oven on implantable unipolar cardiac pacemakers, we measured the distribution profile of the magnetic field intensity, both with and without a pan on the induction oven. We also performed the inhibition test and asynchronous test using four kinds of pacemakers housed in the standardized Irnich human body model, and measured the maximal distance from the induction oven up to which the interference occurred. In the pan-detection mode of the oven in the absence of a pan, the distribution profile of the magnetic field intensity peaked at the center of the cooking plate, and during induction heating of a pan placed on the induction oven, it was the largest at the circular top-edge of the pan. Pacemaker pulses were inhibited by the induction oven, or generated by the reversion mechanism. The maximal interference distance from the oven was 34 cm for one of the pacemakers. Thus, the safe distance from an induction oven of a patient with an implanted cardiac pacemaker is considered to be 50 cm or more. In conclusion, in the pan-detection mode of the oven in the absence of a pan, the distribution profile of the magnetic field intensity peaked at the center of the cooking plate, and during the induction heating of a pan placed on the oven, it peaked at the circular edge of the pan. The induction oven asynchronized or generated pulses in implantable unipolar cardiac pacemakers up to a maximal distance of 34 cm from the induction oven.

Electromagnetic Fields↗
PubMed1987

Genetic variations in kinetic constants that describe beta-glucuronidase mRNA induction in androgen-treated mice.

The kinetics of beta-glucuronidase mRNA induction by androgen in mouse kidney were determined for A, B, and CS haplotypes of the beta-glucuronidase gene. After a lag period, the kinetics of mRNA (R) induction are approximated by the turnover equation dR/dt = k1 - k2R. The A haplotype differs from the B primarily in the duration of the lag period and in k1, the rate constant determining the initial slope of the induction curve. The CS haplotype differs from B primarily in k2, the first-order rate constant that determines the half-time for induction. None of the haplotypes differs significantly in the half-life of beta-glucuronidase mRNA as measured by deinduction. Thus, there was no correlation between the half-time or extent of induction and the half-life of the RNA. Comparing half-times for induction with the half-life of the mRNA suggests that message stabilization can at most account for only part of the induction. We conclude that transcriptional activation of the beta-glucuronidase gene must be an important component of induction. Estimating absolute numbers of mRNA molecules and absolute rates of gene transcription, it appears that before induction there is approximately one molecule of beta-glucuronidase mRNA per cell and that each gene copy is transcribed once every 35 to 40 h. Depending on the haplotype examined, after induction, mRNA goes up to 80 to 400 molecules per induced cell. In the A haplotype, which has the highest induction, this corresponds to one transcript from each gene every 6 min if there is no induced stabilization of beta-glucuronidase mRNA, and one every 30 min if there is. Thus, it seems unlikely that more than one transcript is ever being synthesized at the same time from the beta-glucuronidase gene.

Animals↗
PubMed1995

Induction of c-fos and c-jun gene products and heat shock protein after brief and prolonged cerebral ischemia in gerbils.

BACKGROUND AND PURPOSE: Proto-oncogene activation and induction of heat shock protein (HSP) occur in response to various stimuli to brain, but the role in neuronal survival after cerebral ischemia remains uncertain. We compared the extent of insults and induction of c-fos and c-jun gene products (c-FOS and c-JUN) as well as HSP in ischemic and postischemic gerbil brains immunohistochemically. METHODS: Common carotid arteries of Mongolian gerbils were occluded for 5 or 15 minutes and recirculated for 0 minutes to 7 days. Antibodies for c-FOS, c-JUN, and HSP 70 were used for immunohistochemistry, and positive reactions were semiquantitatively analyzed. The presence of ischemic and postischemic lesions was ascertained with an antibody for microtubule-associated proteins. RESULTS: After ischemia for 15 minutes and reperfusion, c-FOS was induced promptly after 1 to 6 hours in pyramidal cells of the CA3 and CA4 regions, while c-JUN became visible in the same areas after recirculation for 4 to 48 hours. HSP 70 was detected after recirculation for 24 hours in the CA3 region. In layers I and II of the cerebral cortex, c-FOS and c-JUN peaked at 3 hours and HSP 70 at 96 hours. Induction of these proteins was absent or negligible in the areas that developed ischemic or postischemic lesions, including the subiculum-CA1 and CA1 regions of the hippocampus and layers III/IV and Vb/VI of the cerebral cortex. After shorter ischemia for 5 minutes and reperfusion, c-FOS and c-JUN were rapidly induced at 15 minutes to 1 hour except for the subiculum-CA1 and CA1 regions of the hippocampus. Induction of HSP 70 did not occur for 24 hours and was noted only in the hippocampus. CONCLUSIONS: Induction of c-FOS and c-JUN occurred in the areas surviving after transient cerebral ischemia, but the extent of induction and the latent period varied depending on the duration of the insult and the location. In the areas with ischemic or postischemic damage detected by loss of the reaction for microtubule-associated proteins, the induction of c-FOS and c-JUN was either absent or minimal, suggesting that active induction of those immediate early gene products occurred early in surviving neurons. On the other hand, the induction of HSP 70 did not occur until reperfusion for 24 hours and actively occurred only in the areas with earlier induction of c-FOS and/or c-JUN, suggesting that the induction of HSP 70 occurred in neurons that survived to that point, but it did not participate in early responses for neuronal survival after global cerebral ischemia.

Animals↗
PubMed1985

Tissue factor induction in human monocytes. Two distinct mechanisms displayed by different alloantigen-responsive T cell clones.

One component of the cellular immune response to antigens is the expression of procoagulant activity (PCA) by monocytes and macrophages. Induction of human monocyte PCA in response to alloantigenic stimulation requires the collaboration of HLA-DR-responsive T cells. In mixed lymphocyte cultures (MLCs), the induction of monocyte tissue factor appears to be mediated exclusively by a T cell-derived lymphokine. We have used a soft agar cloning method to generate alloantigen-responsive T cell clones from MLCs between irradiated Daudi lymphoblastoid cells and human peripheral blood mononuclear cells. Developing clones were screened for the ability to induce PCA in fresh autologous monocytes in response to Daudi stimulator cells. PCA induction was observed with some, but not all, proliferating T cell clones and two modes of induction were apparent. Some T cell clones mediated PCA induction exclusively by lymphokine production, whereas other clones delivered induction signals by direct cellular collaboration with the monocyte effector cells. These two inductive pathways were represented in distinct, non-inclusive functional subsets of T cell clones. Constitutive production of soluble inducer signals was not observed in T inducer clones. The magnitude of the monocyte PCA response increased in response to an increase in the allogeneic stimulator/T clone responder ratio, and third-party allogeneic cells were unable to elicit the PCA-inducing lymphokine signals from T inducer clones. Both modes of induction were shown to generate tissue factor protein activity in monocytes. Collectively, these results suggest that PCA induction can be initiated in response to alloantigens through collaboration with certain OKT3+, OKT4+, OKT8-, OKM1- T inducer clones, and that induction can be mediated by at least two different functional subsets of human T cells. Stimulation with the appropriate alloantigen may elicit both lymphokine and T cell-contact pathways of induction of tissue factor in human monocytes.

Antigens, Differentiation, T-Lymphocyte↗
PubMed2003

Sputum induction leads to a decrease of exhaled nitric oxide unrelated to airflow.

Measurement of exhaled nitric oxide (eNO) and analysis of induced sputum are both established noninvasive methods for studying airway inflammation in asthma. Both methods are often used sequentially within short time frames. The aim of the present study was to evaluate the influence of sputum induction on eNO in adults and to follow the kinetics of airway eNO production after induction in relation to forced expiratory volume in one second (FEV1). eNO and FEV1 were measured in 41 adult patients (aged 29 (range 23-50) yrs, 56% male) with asymptomatic atopy or mild asthma (mean FEV1 97.2+/-3% predicted) prior to and immediately after sputum induction with hypertonic saline (4%). Sputum induction with isotonic saline was also performed in 13 subjects (control group). Repeatability of eNO decrease after sputum induction was also studied in 27 patients on separate occasions and kinetics of eNO production after sputum induction were followed over 24 h in another 10 patients. Sputum induction with hypertonic, but not isotonic, saline led to a marked decrease in eNO (log) immediately after the procedure (pre: 3.85+/-0.13 parts per billion (ppb); post: 3.24+/-0.14 ppb). This decrease was shown to be highly reproducible and not related to a fall in FEV1 following sputum induction. While FEV1 returned to baseline within 1 h, decreased eNO levels were observed over 4 h and returned to baseline after 24 h. Hypertonic saline sputum induction leads to a prolonged reduction in exhaled nitric oxide in adult atopics that is reproducible within subjects and not related to a reduction in airflow following sputum induction. This methodological interference should be taken into account when sputum induction and exhaled nitric oxide measurements are performed in the same subject.

Adult↗