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PubMed1986

Induction of 2',5'-oligoadenylate synthetase and blast transformation in primary chronic lymphocytic leukemia cells following exposure to interferon in vitro.

Interferon (IFN) can induce blast transformation and differentiation of malignant cells from patients with chronic lymphocytic leukemia (CLL). In this work the capacity of IFN to induce 2',5'-oligoadenylate synthetase (2',5'-A synthetase) in lymphoid cells from patients with CLL was investigated, and the results were related to the induction of blast transformation. IFN induced enhanced levels of 2',5'-A synthetase in unseparated lymphoid cells from 18 of 24 patients with CLL. In a control group of 11 healthy donors, 2',5'-A synthetase was induced in all cases tested. There was a close correlation between induction of 2',5'-A synthetase and induction of blast transformation by IFN. Thus, transformation occurred in clones expressing enhanced levels of 2',5'-A synthetase, but not in those showing no increase in 2',5'-A synthetase. An enhancement of 2',5'-A synthetase was observed in the IFN-sensitive cells following exposure to concentrations as low as 0.5 IFN units/ml. For induction of blast transformation, 10-1000 times more IFN was required. One h of pretreatment was sufficient for induction of 2',5'-A synthetase, whereas 20 h of pretreatment were required for induction of transformation by IFN. The finding that induction of 2',5'-A synthetase parallels interferon-induced blast transformation indicates that the reason why some CLL clones do not differentiate following exposure to IFN is a resistance of these cells to the action of IFN. The resistance to IFN in some CLL clones may be due to a defect in the 2',5'-A synthetase system of the cells, but it could also be at an early stage of the interaction between IFN and the cell, for instance at the receptor level.

2',5'-Oligoadenylate Synthetase↗
PubMed1989

Synergistic effects of phorbol ester and INF-gamma on the induction of indoleamine 2,3-dioxygenase in THP-1 monocytic leukemia cells.

Indoleamine 2,3-dioxygenase (IDO) is a flavin-dependent enzyme which uses superoxide anion as a cosubstrate to catalyze the decyclization of the pyrrole ring of L-tryptophan to form formylkynurenine. This enzyme is induced in some tumor cells after treatment with IFN-gamma. The mechanism of induction of IDO in tumor cells by IFN-gamma was studied in THP-1 human monocytic leukemia cells. Before the addition of IFN-gamma, no IDO could be detected in these cells. Treatment of THP-1 cells with IFN-gamma produced an induction of IDO, with peak activity occurring 72 to 96 h after addition of IFN-gamma. Because phorbol esters are known to induce many enzymes in cells, most likely through the activation of protein kinase C, the effects of PMA on the induction of IDO were determined. PMA potentiated the IFN-gamma-induced elevation of IDO, but by itself, was unable to induce enzyme activity. Maximum induction of IDO in the presence of PMA and IFN-gamma was obtained by preexposure of the cells to PMA for 48 h before the addition of IFN-gamma. Maximum induction of IDO after the addition of IFN-gamma occurred 24 to 48 h after addition of the cytokine to the culture medium. However, the induction of IDO does not appear to be potentiated through the activation of protein kinase C, because the addition of the protein kinase C inhibitor H-7 had no effect on the induction of IDO when the cells were exposed to PMA and IFN-gamma. Moreover, diacylglycerol was unable to replace PMA in these studies. Studies with cAMP and cGMP analogs suggest a role for these compounds in the regulation of IDO expression.

Cyclic AMP↗
PubMed1987

Induction of virus enzymes by phorbol esters and n-butyrate in Epstein-Barr virus genome-carrying Raji cells.

Phorbol esters and n-butyrate (SB) together could induce Epstein-Barr virus (EBV) DNA polymerase and DNase activities in Raji cells (virus nonproducer). Neither 12-O-tetradecanoylphorbol-13-acetate (TPA) nor SB alone could induce these EBV enzyme activities, transcription of the EcoRI C-region or other EBV proteins in Raji cells. The enzyme induction caused by exposure of Raji cells to TPA-SB was the result of the synthesis of virus-specified RNA, and the increase of linear EBV DNA content in Raji cells caused by TPA alone was not sufficient for induction of EBV-enzyme activities. Temporal characteristics of the TPA-SB induction process, but not the phorbol 12,13-dibutyrate-SB induction process, in Raji cells were observed; a critical phase (10-24 h) postphorbol ester treatment in phorbol 12,13-dibutyrate-SB-treated Raji cells which was responsible for the synthesis of virus RNA and enzymes was found. Phospholipase C, which increases intracellular diacylglycerols (and subsequently activates protein kinase C) was able to partially substitute for TPA in the TPA-SB induction for EBV polymerase and DNase activities. Sphingosine, a protein kinase C inhibitor, partially prevented the induction of virus enzyme activities in Raji cells treated with phorbol 12,13-dibutyrate and SB. No apparent changes in the methylation state of EBV DNA (EcoRI C region) were observed when Raji cells were treated with SB and TPA, alone or in combination. These results suggest that induction of EBV polymerase and DNase activities by TPA-SB may involve protein kinase C activation and another factor triggered by SB which together increase transcription of EBV DNA.

Burkitt Lymphoma↗
PubMed1988

Mechanism of induction of mouse kidney alcohol dehydrogenase by androgen. Androgen-induced stimulation of transcription of the Adh-1 gene.

The three alcohol dehydrogenase genes in the mouse are subject to developmental, hormonal, and genetic control as revealed by variation in expression among inbred strains. The primary purpose of this study was to determine the mechanism by which androgen regulates the expression of the Adh-1 gene in kidney. In addition, the fold-induction in several inbred strains was examined in a search for possible genetic variation in the induction process, and Adh-1 expression in several tissues was studied. Testosterone treatment of female mice results in a 10-12-fold increase in alcohol dehydrogenase activity and a corresponding increase in the rate of enzyme synthesis accounts for this induction. The induction of Adh-1 mRNA after androgen treatment is sufficient to account for the induction in enzyme synthesis. An increase in Adh-1 transcription accounts for a substantial part of the increase in Adh-1 mRNA level following androgen simulation. This conclusion was reached using nuclear "run-on" assays, in vivo labeling, and a kinetic analysis of Adh-1 mRNA accumulation and loss in response to hormone. This induction requires androgen receptor. The fold induction by androgen of Adh-1 mRNA is similar in eight inbred mouse strains. There is almost a 100-fold variation in Adh-1 mRNA concentrations among various mouse tissues. Tissues with lowest level of expression are brain and heart, while liver and adrenals have the highest content of Adh-1 mRNA.

Alcohol Dehydrogenase↗
PubMed1988

Role of acetone, dietary fat and total energy intake in induction of hepatic microsomal ethanol oxidizing system.

Chronic ethanol consumption results in the induction of a specific hepatic cytochrome P-450 (P450IIE1). However, since compounds other than ethanol (i.e., acetone) can also serve as P450IIE1 inducers, and since ethanol given with a normal fat-containing (35% of energy) diet is associated with acetonemia, hepatic steatosis and decreased body weight gain, the question has been raised whether induction is mediated specifically by ethanol or whether it might represent a nonspecific response to these other factors. This was investigated by varying both the mode of ethanol administration and the composition of the diet. By administering ethanol in the drinking water, or as part of a low-fat (5% of energy) liquid diet, a significant induction of P450IIE1 and of the activities of the microsomal ethanol oxidizing system and p-nitrophenol hydroxylase was demonstrated in the absence of any significant increase in blood acetone with minimal increase in liver total lipids. Induction of P450IIE1 was comparable with the low or normal fat-containing diets, but MEOS activity rose more with the latter, possibly reflecting a potentiating effect of dietary fat on ethanol oxidation by P-450 enzymes other than P450IIE1. When the lack of weight gain of the alcohol fed animals was mimicked in controls by decreasing the amount of diet ingested, no induction was observed. Varying the pattern of liquid diet feeding had no demonstrable differential effect. Thus, the induction of P450IIE1 after chronic ethanol consumption can be attributed to ethanol itself, but dietary fat can potentiate the induction of the microsomal ethanol oxidizing system and of p-nitrophenol hydroxylase.

Acetone↗
PubMed1982

Sex-related difference in the effect of clofibric acid on induction of two novel long-chain acyl-CoA hydrolases in rat liver.

The sex differences in the induction of two novel long-chain acyl-CoA hydrolases in hepatic cytosol of rats by clofibric acid (p-chlorophenoxyisobutyric acid)-feeding and the properties of the induced acyl-CoA hydrolases were investigated. Marked sex-related difference was observed in the induction of acyl-Coa hydrolase activity. The sex difference was mainly due to the difference in the induction of acyl-CoA hydrolase with higher molecular weight (hydrolase I), but not to the difference in the induction of acyl-CoA hydrolase with lower molecular weight (hydrolase II). The extent of the induction of the hydrolase I in hepatic cytosol of male rats was 3.5 times over that of female rats. Castration of male rats resulted in the marked depression of the ability to induce hydrolase I. The administration of testosterone to the castrated male rats recovered completely the ability to induce hydrolase I. Unlike hydrolase I, the ability to induce hydrolase II did not respond to the changes in state of androgen. The administration of di-(2-ethylhexyl)phthalate also induced both hydrolase I and II, although the extent of the induction of hydrolase I was less compared to that by clofibric acid treatment. Likewise, marked sex difference was observed in the induction of the hydrolase I on di-(2-ethylhexyl)phthalate administration. These two hydrolases showed different kinetic properties and different substrate specificities to each other. Hydrolase I was inhibited by bovine serum albumin in vitro, but was not affected by Mg2+. Hydrolase II was activated slightly in the presence of lower concentrations of bovine serum albumin, Mg2+ or Ca2+.

Animals↗
PubMed1980

Ornithine decarboxylase induction during B1 progression of normal and Rous sarcoma virus-transformed cells.

Ornithine decarboxylase (ODC) induction during G1 phase of the cell cycle was compared in Rat-1 fibroblasts and in Rat-1 fibroblasts transformed by the B77 wild-type Rous sarcoma virus (RSV) and by the thermosensitive mutant LA24/RSV. In Rat-1 cells, maximal enzyme activity detectable at mid G1 declined to basal levels by G1-S. The ODC increase was inhibited by actinomycin D and cycloheximide and was dependent on the addition of serum growth factors. Rat-1 (B77 wild-type RSV) cells expressed a greater amount of enzyme activity after serum stimulation, and the maximal level of enzyme activity detectable at mid G1 declined only 50% so that elevated ODC was maintained during G1-S transition. The enzyme increase in the transformed cell line was not dependent on serum growth factors. Fresh medium addition alone induced enzyme activity. Induction in the presence or absence of serum required both RNA and protein synthesis. ODC induction in the transformed cells was less sensitive to repression by exogenous putrescine addition. A 100-fold greater concentration of the diamine was required to produce comparable inhibition in the Rat-1 (B77 wild-type RSV) as compared to the Rat-1 cell. These alterations in the characteristics of ODC expression were found to be a consequence of the transforming function of RSV in the Rat-1 cell line transformed by the thermosensitive viral mutant LA24. In response to serum stimulation at the nonpermissive temperature (39 degrees), Rat-1 (thermosensitive mutant LA24/RSV) cells displayed a discrete G1-phase ODC induction while those cells maintained at the permissive temperature (35 degrees) exhibited a greater and prolonged ODC induction in G1 and S phases. A shift from 39 to 35 degrees in the absence of any medium or serum addition stimulated the induction of ODC expressed in a transformed phenotypic manner. Greater concentrations of exogenous putrescine were required to repress the induction of ODC at 35 than at 39 degrees. Alterations in ODC regulation, therefore, may be inherent to the neoplastic phenotypic change.

Animals↗
PubMed1995

Bone marrow morphology during induction phase of therapy for acute myeloid leukemia (AML).

Sequential bone marrow aspirates and sections from patients with acute myeloid leukemia (AML) were examined to determine if a correlation exists between bone marrow morphology during induction phase of therapy and outcome. Of 95 patients of AML diagnosed between July 1987 and December 1991, 53 uniformly treated patients (induction therapy with cytosine arabinoside and daunorubicin) had sequential bone marrow examinations performed in the 2- to 5-week period following initiation of induction therapy. Four morphologic patterns were recognized in these 53 patients: Group I (22 patients)--hypocellularity or normal regeneration (> or = 15% cellularity and < 5% blasts) on the initial 2-week marrow followed by marrows showing normal regeneration; Group II (10 patients)--hypocellularity followed by "reactive myeloblastosis" (> or = 15% cellularity, 5% to 34% blasts, with promyelocytes = or > blasts); Group III (12 patients)--residual blasts (> or = 5% blasts with blasts >> promyelocytes) in the initial posttherapy marrow; Group IV (9 patients)--atypical patterns not fitting any of the other categories. Complete remission was achieved in all 32 patients in Groups I and II without additional induction therapy, but was achieved eventually in only 10 of 21 patients in Groups III and IV combined (p < 0.005), 15 of whom received additional induction therapy. Remission duration and actuarial survival for each group were as follows: Group I: 344/596 days; Group II: 443 days/> 660 days; Group III and IV combined: 351/311 days (p = 0.017 for actuarial survival). Seven of 21 patients in Groups III and IV had unfavorable initial morphology (MO, hypoplastic AML and AML preceded by myelodysplasia) compared to only 3 of 32 patients in Groups I and II (p = 0.039). It was thus observed that "reactive myeloblastosis" with up to 34% blasts on the third or fourth week bone marrow following an initial hypocellular marrow does not require additional induction therapy to achieve durable remissions or favorable survival. Also, residual blasts that outnumber promyelocytes, and atypical patterns of regeneration correlate with lower remission induction rates, shortened survival, and unfavorable morphology on the initial diagnostic bone marrow.

Adult↗
PubMed1994

Relationship between Daunorubicin dosage delivered during induction therapy and outcome in adult acute lymphoblastic leukemia.

The long-term results of a therapeutic regimen for adult acute lymphoblastic leukemia (ALL) have been analysed with the main purpose to evaluate the impact of Daunorubicin (DNM) dosage given during the induction. The files of 86 consecutive adult ALL patients treated in our institution between 1974 and 1988 were reviewed. They received the same induction regimen based on Vincristine, DNM and Prednisone, consolidation with L-Asparaginase, central nervous system prophylaxis, and 3-year maintenance with 6-mercaptopurine and Methotrexate with periodic cycles of reinduction. We analysed the overall and disease-free survival (DFS) in relation to various prognostic factors, focusing on the dosage of DNM actually received during the induction period. Complete remission (CR) was achieved in 68 (79%) patients and the overall DFS was of 32 months (median follow-up 37 months); 22 patients (25.6%) are off-therapy and disease-free. The actual dosage of DNM received during induction turned out to be an independent DFS prognostic factor. In fact, patients who received more or less than 175 mg/sqm in induction had a median DFS of 44 and 12 months, respectively (p = 0.05). The plateau of DFS in the two groups was 44% and 21%, respectively. Similar data were found analyzing the dose-intensity (mg/sqm/week) of DNM given in induction. Our data suggest that the actual dosage of DNM given in induction plays a role in the long term DFS of adult ALL.

Adolescent↗
PubMed1996

Phenobarbital induction of hepatic CYP2B1 and CYP2B2: pretranscriptional and post-transcriptional effects of gender, adult age, and phenobarbital dose.

Chemical induction of hepatic monooxygenases should not be viewed as an extracorporal process but rather as one that is liable to be influenced by numerous endogenous factors. In this regard, we examined the interactions of gender, adult age, and barbiturate dose on the course of phenobarbital induction of hepatic CYP2B1 and CYP2B2. We observed that femaleness and youth were associated with the greatest inhibition, so that both the rate and initiation of CYP2B1 and CYP2B2 induction were suppressed most in the young adult (65 days of age) females, followed by the mature adult (150 days of age) females and then by the young adult males, with the mature adult males exhibiting the least suppression of phenobarbital induction. The differential expression rates of hepatic CYP2B1 mRNA in the young and mature male and female rats, similarly reflected at the protein level, suggest that gender- and age-dependent suppression of CYP2B1 occurs at a pretranscriptional or transcriptional level. In contrast, transcript levels of CYP2B2 were unaffected by gender or age. However, accumulation of cytochrome P450 (P450) 2B2 protein was affected by the animal's age and gender, suggesting regulation of a post-transcriptional event. Highly selective (androstenedione 16beta-hydroxylase) as well as nonspecific (total P450 and hexobarbital hydroxylase) P450 2B1- and 2B2-dependent catalytic activities were in agreement with protein levels. Determination of gender- and age-dependent circulating growth hormone profiles indicates that the continuous secretion of the hormone characteristic of the female is more suppressive of CYP2B induction than the episodic pattern growth hormone secretion found in males. The considerably elevated growth hormone pulse amplitudes observed in the young rats of both genders seem to be an additional inhibitory signal antagonizing phenobarbital induction of CYP2B1 and CYP2B2. Phenobarbital administration did not interfere with the normal gender- and age-dependent growth hormone secretory profiles. Last, although as little as 1 mg/kg phenobarbital increased CYP2B1 mRNA concentrations by 100%, there was no translation into detectable levels of protein. In contrast, the same low dose of barbiturate inducing an equal percent increase in CYP2B2 mRNA did result in an expression of protein. Unlike use of the 10 mg/kg dose, CYP2B1 and CYP2B2 induction by phenobarbital at 1 mg/kg was unaffected by age or gender.

Age Factors↗
PubMed1996

Caffeine induces cytochrome P4501A2: induction of CYP1A2 by tea in rats.

Previous reports indicated that treatment of rats with green tea or black tea extracts increased CYP1A2 activity, but such an induction was not observed with decaffeinated green tea in our preliminary study. Herein we report a comparative study on the induction of CYP1A2 with different tea preparations and caffeine as an inducer. When green tea (2%) or black tea (2%) was given to male Fischer 344 rats as the sole source of drinking fluid for 21 days, a 2.4- or 2.7-fold induction, respectively, of CYP1A2-dependent O-methoxyresorufin demethylase (MROD) activity in liver microsomes was observed. Treating rats with caffeine (0.04%) also resulted in an 1.9-fold increase in the MROD activity, but decaffeinated green tea (0.8%) did not cause such an induction. Rats treated with green tea (2%) or caffeine (0.055%) as the sole source of drinking fluid for 1, 3, and 7 days also showed comparable induction (from 1.7- to 2.1-fold) of the MROD activity. The induction was also shown by intragastric administration of caffeine (100 mg/kg). The induced MROD activity caused by consumption of green tea, black tea, and caffeine corresponded to the increase in liver microsomal CYP1A2 protein, as determined by immunoblot analysis. The concentrations of tea polyphenols and caffeine in plasma were also measured. Close correlation of the increase in the MROD activity was observed only with the plasma caffeine level (r = 0.736, n = 10, p = 0.015), not with the combined tea polyphenol level (r = 0.058, n = 6, p = 0.913). The present study establishes caffeine as an inducer of CYP1A2 and demonstrates that caffeine, not tea polyphenols, is the component in tea responsible for the induction of this enzyme.

Animals↗
PubMed1996

Interaction of styrene and ethylmethylketone in the induction of cytochrome P450 enzymes in rat lung, kidney and liver after separate and combined inhalation exposures.

The present study compares the induction of different cytochrome P450 forms (CYP1A1/2, 2B1, 2E1) after pretreatment with styrene, ethylmethylketone separately or in combined exposures. Combined exposures lead to cumulative elevation of CYP levels, except for CYP1A1 and 2B1. Induction of CYP1A1 was higher in liver and kidney respectively and did not change significantly with the pretreatment mode. Styrene produced two times higher induction of CYP1A2 in the lung and kidney than ethylmethylketone. The simultaneous application of both inducers lead to significantly higher induction of CYP1A2 than that estimated after pretreatment with each of the inducers separately. CYP2B1 was induced by styrene to higher extent in the liver, where it was almost indetectable in controls. Major form of cytochrome P450 induced by styrene proved to be CYP2E1--about 3-fold induction of chlorzoxazone hydroxylation activity in the liver and 2.5 times in the lung. Ethylmethylketone significantly potentiated the CYP2E1 induction ability of styrene. This induction of CYP2E1-dependent catalytic activity correlates with the enzyme levels detected by immunoblotting.

Animals↗
PubMed1997

Pharmacokinetic consequences of induction of CYP2E1 by ligand stabilization.

Models of the time course of the effect of P450 induction on substrate clearance have previously only considered induction through enhanced synthesis of protein. Induction of CYP2E1 does not always conform to this model, in that many chemicals induce the enzyme through stabilization of the protein apparently by binding to the active site. While such binding protects the enzyme from degradation, it also results in competitive inhibition of substrate clearance. We present a model based on experimental studies of chemical induction of CYP2E1 by ligand stabilization through which this mechanism of induction can be translated into its pharmacokinetic consequence with regard to clearance of substrate. CYP2E1 is considered to be localized in two pools: Pool 1 at which two mechanisms of degradation, fast and slow, operate and pool 2, at which only the slower mechanism operates. Binding of substrate to enzyme in pool 1 stabilizes it from degradation by the fast process, leaving only the slow process. Ligand stabilization therefore results in induction of CYP2E1 as enzyme accumulates as a consequence of unchanged synthesis. Binding of ligand to the active site results in competitive inhibition of the clearance of substrate. Model-based computer simulations show that the time course of interaction between inhibitor/inducer and substrate can be predicted from knowledge of I/Ki and S/Km and the synthesis and degradation kinetics of CYP2E1. The simulations demonstrate further that as long as inhibitor/inducer administration is not interrupted, the clearance of substrate will always be less than the value observed at low concentration of substrate even if the substrate concentration is raised to displace inhibitor/inducer from the active site. On the other hand, the degree of inhibition of clearance is less than would be seen if induction had not taken place. Clearance of substrate is observed to rise above the value observed in the absence of the inhibitor/inducer only after the inhibitor/inducer concentration declines low enough for substrate to gain access to the active site of the enzyme. The model-based simulations agree with reports of the interaction between isoniazid and acetaminophen in humans.

Acetaminophen↗
PubMed1998

What is the best induction regimen for acute myelogenous leukemia?

The pursuit of the best induction regimen for acute myelogenous leukemia (AML) continues in an attempt to improve complete response rates and long-term disease free and overall survival. At this time, standard induction therapy generally consists of an anthracycline, most commonly daunorubicin given at a dose of 45-60 mg/m2 intravenously for 3 days and cytarabine arabinoside (ara-C) given at a dose of 100-200 mg/m2 intravenously by continuous infusion for 7 days. This regimen is based on findings from classic studies conducted from the late 1960s through the 1980s. Research on intensifying induction therapy has continued over the past decade. Potential strategies for intensifying induction therapy include (1) modulation of the anthracycline dose or agent; (2) modulation of ara-C; (3) the addition of other agents to standard induction therapy; (4) timed-sequential therapy; and (5) very early intensification therapy. Accurate interpretation of results from studies of intensifying induction therapy requires consideration of variables such as patient age, study inclusion criteria (eg, antecedent myelodysplasia), supportive care and, most importantly, patient selection. Furthermore, any benefit in long-term outcome during induction cannot be determined without regard to the choice of postremission therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

A comparison of oral misoprostol tablets and vaginal prostaglandin E2 pessary in induction of labour at term.

OBJECTIVE: To compare the cost-effectiveness, mode of delivery, fetal and maternal outcome of oral Misoprostol and vaginal prostaglandin E2 pessary in induction of labour at term. DESIGN: Randomized clinical trial. PLACE AND DURATION OF STUDY: Hamdard University Hospital, Imam Clinic and General Hospital from February 2002 to January 2003. PATIENTS AND METHODS: The trial was conducted over two groups of patient for labour induction such that Group A received 50 microg oral Misoprostol 4 hourly to a maximum of four doses. Group B received prostaglandin E2 vaginal pessary at 6 hourly intervals upto two doses. Labour induction, number of doses, need of augmentation, induction to delivery time interval, mode of delivery and neonatal outcome were the main outcomes. Test of proportions was used to compare the significance between both managements. RESULTS: Out of a total of 214 women, 106 received oral Misoprostol and 108 received PGE2 vaginal pessary. Ninety-three percent women in misoprostol group were successfully induced compared with 91% in PGE2 group. A significant response of labour induction with the minimal dose (58%, p = 0.001) and earlier induction to vaginal delivery (74%, p = 0.01) was observed in Misoprostol group. Rate of operative delivery was also less (16%, p = 0.16) compared with PGE2 group (25%). CONCLUSION: Oral Misoprostol administration was more efficient and cost-effective than PGE2 vaginal pessary for induction of labour due to earlier response with minimal dose and less number of operative deliveries.

Administration, Intravaginal↗
PubMed2004

Ventromedial prefrontal cortex and amygdala dysfunction during an anger induction positron emission tomography study in patients with major depressive disorder with anger attacks.

CONTEXT: Although a variety of functional neuroimaging studies have used emotion induction paradigms to investigate the neural basis of anger in control subjects, no functional neuroimaging studies using anger induction have been conducted in patient populations. OBJECTIVE: To study the neural basis of anger in unmedicated patients with major depressive disorder with anger attacks (MDD + A), unmedicated patients with MDD without anger attacks (MDD - A), and controls. DESIGN: We used positron emission tomography, psychophysiologic measures, and autobiographical narrative scripts in the context of an anger induction paradigm. SETTING: Academic medical center. PARTICIPANTS: Thirty individuals, evenly divided among the 3 study groups. INTERVENTIONS: In separate conditions, participants were exposed to anger and neutral autobiographical scripts during the positron emission tomography study. Subjective self-report and psychophysiologic data were also collected. MAIN OUTCOME MEASURES: Voxelwise methods were used for analyses of regional cerebral blood flow changes for the anger vs neutral contrast within and between groups. RESULTS: Controls showed significantly (P<.001) greater regional cerebral blood flow increases in the left ventromedial prefrontal cortex during anger induction than patients with MDD + A, whereas these differences were not present in other between-group analyses. Also, in controls, an inverse relationship was demonstrated between regional cerebral blood flow changes during anger induction in the left ventromedial prefrontal cortex and left amygdala, whereas in patients with MDD + A there was a positive correlation between these brain regions during anger induction. There was no significant relationship between these brain regions during anger induction in patients with MDD - A. CONCLUSION: These results suggest a pathophysiology of MDD + A that is distinct from that of MDD - A and that may be responsible for the unique clinical presentation of patients with MDD + A.

Adult↗
PubMed1997

Induction of heat shock protein 70 protects thymocytes against radiation-induced apoptosis.

OBJECTIVES: To determine if induction of heat shock protein 70 (HSP 70), a stress protein that plays a cytoprotective role and inhibits cell death in response to various stimuli, will protect thymocytes and T-cell clones from radiation-induced apoptosis, and to define the mechanism of such protection. DESIGN: Thymocytes from BALB/c mice or T-lymphocyte clones were incubated at 43 degrees C for 1 hour to induce HSP 70, then irradiated. Control cells were irradiated but not heated. Fragmentation of DNA was quantitated, and p53, bax, and bcl-2 expression was analyzed at various times by the Western blot method. RESULTS: Only heated cells expressed HSP 70. The induction of HSP 70 increased basal apoptosis but significantly decreased radiation-induced apoptosis. Furthermore, introduction of an HSP 70 antisense oligomer prior to heating reversed the protective effect of HSP 70. Induction of HSP 70 in T-cell clones with sodium arsenite had a similar protective effect against radiation-induced apoptosis. Irradiation induced p53 and markedly up-regulated bax. The expression of p53 peaked at 4 hours and preceded maximal bax induction. Induction of HSP 70 prior to irradiation suppressed p53 and significantly decreased bax levels. Levels of bcl-2 were unaffected. CONCLUSIONS: Our data show that HSP 70 induction protects thymocytes from radiation-induced apoptosis by down-regulating p53 and bax expression. The induction of HSP 70 may represent a novel mechanism by which the immunosuppressive effects and the associated infectious complications of radiation therapy can be minimized.

Animals↗
PubMed1998

Effect of post-induction nutrient feeding strategies on the production of bioadhesive protein in Escherichia coli.

The effect of post-induction nutrient feeding strategies on the production of bioadhesive protein using an IPTG inducible expression system in Escherichia coli was investigated. Cells were cultured in an exponential fed-batch mode to the OD600 of ca. 100 (48 gDCW/L) prior to induction. Six different post-induction nutrient feeding strategies (pH-stat, exponential, constant and linear change in feeding rate with three different slopes) were then applied, and bioadhesive protein production was examined. It was found that post-induction cell growth was independent of nutrient feeding rate. However, bioadhesive protein production was significantly affected by post-induction feeding strategies. Linearly changing post-induction feeding rate with a suitable slope allowed production of bioadhesive protein up to 5.3 g/L, which was higher than that obtained by the other post-induction feeding strategies.

Animals↗