Power spectral analysis of arterial and central venous pressure signals during graded hemorrhage in anesthetized rats

Based on simultaneous power spectral analysis of systemic arterial pressure (SAP) and central venous pressure (CVP) signals in rats anesthetized with pentobarbital sodium, we assessed the hypotheses that subtle changes in the SAP spectrum exist during hemorrhagic shock, and that the CVP spectrum is a feasible index for central blood volume during acute graded blood loss. During Stage I hemorrhagic shock seen after reduction in 10% of total blood volume (TBV), there was a significant increase in the power of both the very low frequency (VLF, 0-.25 Hz) and low frequency (LF, .25-.8 Hz) components, along with a moderate decrease in the very high frequency (VHF, 5-9 Hz) component, of SAP signals. Substantial reduction in VLF, LF, and VHF components in the SAP spectrum occurred after a blood loss of 25% of TBV (Stage II), which persisted during Stage III hemorrhagic shock when the withdrawn blood reached 50% of TBV and the mean SAP maintained at 40 mm Hg. The depressed SAP-VLF and SAP-LF components sustained the period of spontaneous recovery and subsequent retransfusion of shed blood, although the power of SAP-VHF component gradually elevated during these two periods. The power of the high-frequency (HF, .8-2.4 Hz) component of SAP signals increased discernibly only during Stage III, became significant on spontaneous recovery, and declined during retransfusion. Although CVP and CVP-VHF component progressively declined, the power of the CVP-HF component manifested a gradual increase that was significantly and reversely correlated with the reduction in TBV. We conclude that differential changes in individual components of the SAP spectrum occur during hemorrhagic shock, and that the CVP-HF component may be a reliable indicator for central blood volume during acute graded blood loss.

Edwardsiella tarda bacteraemia--complicated by acute pancreatitis and pyomyoma

Edwardsiella tarda (E. tarda) has recently become recognized as a pathogen in humans. Here we report a new case of E. tarda bacteraemia complicated by acute pancreatitis and pyomyoma. A 46-year-old female came to our emergency room complaining of sudden onset of left upper quadrant pain and vomiting for the previous few hours after drinking three bottles of wine. An abdominal computed tomography (CT) scan revealed multiple biliary stones, acute pancreatitis with extensive inflammatory change, and a large uterine myoma. Fever, watery diarrhoea, and mild suprapubic discomfort with vaginal spotting were noted soon after admission. The patient's blood cultures yielded E. tarda and symptoms subsided after antibiotic therapy. Fever and severe suprapubic pain with rebound tenderness developed 12 days later. Repeat abdominal CT scan revealed an enlarged uterine myoma with central necrosis. The patient subsequently underwent anterior total hysterectomy and bilateral salpingo-oophorectomy, revealing a uterine myoma with infarction and abscess formation. The patient recovered uneventfully and was discharged 1 week later.

Genetic interactions of the Arabidopsis flowering time gene FCA, with genes regulating floral initiation

The genes controlling the timing of the transition from vegetative to reproductive growth are likely candidates for regulators of genes initiating floral development. We have investigated the interaction of one particular gene controlling flowering time, FCA, with the meristem identity-genes TERMINAL FLOWER 1 (TFL1), APETALA 1 (AP1) and LEAFY (LFY) and the floral repression gene EMBRYONIC FLOWER 1 (EMF1). Double mutant combinations were generated and the phenotypes characterized. The influence of strong and intermediate fca mutant alleles on the phenotype conferred by a 35S-LFY transgene was also analysed. The results support a model where FCA function promotes flowering in multiple pathways, one leading to activation of LFY and AP1, and another acting in parallel with LFY and AP1. Only the latter pathway is predicted to be non-functional in the intermediate fca-4 allele. The results are also consistent with AP1 and TFL1 negatively regulating FCA function. Combination of Columbia fca and emf1 mutant alleles confirmed that FCA is required for the early flowering of emf1. EMF1 and FCA are therefore likely to operate in different floral pathways.

EGF induces nuclear translocation of STAT2 without tyrosine phosphorylation in intestinal epithelial cells

Signal transducers and activators of transcription (STATs) are cytoplasmic proteins that bind to activated membrane receptors, undergo ligand-dependent phosphorylation on tyrosine residues, and translocate to the nucleus, where they induce transcription of specific genes in response to a variety of ligands, including cytokines and some growth factors. Using immunocytochemical and biochemical techniques, we investigated the localization and responses of STAT1 and STAT2 to epidermal growth factor (EGF) stimulation in IEC-6 intestinal epithelial cells and HeLa cells. These studies provide the first description of STAT activation and localization in response to EGF in intestinal epithelial cells and some novel findings regarding the activation and localization of STATs in general. These include the following. First, EGF promoted the tyrosine phosphorylation of STAT1 in IEC-6 cells and caused its translocation to the nucleus. Second, in the absence of EGF stimulation both STAT1 and STAT2 were localized to the Golgi apparatus in IEC-6 cells. Third, EGF caused the translocation of STAT2 to the nucleus in both IEC-6 and HeLa cells without inducing the tyrosine phosphorylation of STAT2.

Thioureas differentially induce rat hepatic microsomal epoxide hydrolase and rGSTA2 irrespective of their oxygen radical scavenging effect: effects on toxicant-induced liver injury

Thioureas have been employed as potent hydroxyl radical scavengers and also inhibit production of oxygen free radicals. The in vitro oxygen radical scavenging effect by N,N'-substituted thioureas including dimethylthiourea (DMT), diethylthiourea (DET), tetramethylthiourea (TMT) and diphenylthiourea (DPT) was assessed by the conversion of phi x-174 DNA from supercoiled DNA to the open circular form or to fragmented DNA. Addition of the N,N'-substituted thioureas to the incubation mixture significantly prevented a single strand breakage of phi x-174 DNA induced by autooxidation of benzenetriol. These thioureas were also effective in preventing degradation of phi x-174 DNA induced by autooxidation of benzenetriol in the presence of ferrous iron. In view of the in vitro radical scavenging effect by the thioureas and the role of reactive oxygen species in the induction of phase II detoxifying enzymes, expression of microsomal epoxide hydrolase (mEH) and rGSTA2 in response to these agents was investigated in the rat liver. Rats treated with each of the alkylthioureas exhibited marked increases of mEH and rGSTA2 mRNA levels with TMT being the most effective. DPT an arylthiourea, however, was minimally active in increasing the mRNAs. Time-course studies revealed that DMT, DET and TMT increased the mRNA levels to the greatest extent at 24 h after a single dose of treatment. The levels of mEH and rGSTA2 mRNA were elevated in a dose-dependent manner by the alkylthioureas. Immunoblot analysis showed that the alkylthioureas induced mEH and rGSTA2 proteins in the liver (0.6 mmol/kg per day, 3 days), which was consistent with the increases in the mRNA levels. DMT, DET or TMT enhanced CCl4-induced liver toxicity, as monitored by plasma aminotransferase activity, although each of the agents alone caused only slight increase in the alanine aminotransferase activity. In contrast to the effects of the alkylthioureas, DPT protected the liver against the toxicant-induced injury. All of the thioureas prevented decreases in the hepatic glutathione level by CCl4. Expression of cytochrome P450 2E1 and P450 2B1/2, which are implicated with metabolic activation of CCl4, was assessed after treatment with the thioureas. P450 2E1 and P450 2B1/2 were differentially induced by the alkylthioureas with the expression of P450 2E1 being inversely related with that of P450 2B1/2. These results showed that N,N'-substituted alkylthioureas were capable of inducing mEH and rGSTA2 in the liver with elevation of the mRNAs, that induction of mEH and rGSTA2 by these alkylthioureas might be mediated by production of the reactive oxygens derived from metabolic activation of the agents irrespective of their radical scavenging effect and that the agents rather enhanced toxicant-induced liver injury with the induction of P450 2E1 or P450 2B1/2.

Inappropriate sexual behaviors in dementia: a preliminary report

We investigated types of inappropriate sexual behavior (ISB) and patient characteristics in geriatric patients with dementia. The study group consisted of 133 consecutive geropsychiatric demented patients admitted to our ward. All patients underwent standardized diagnostic procedures for dementia, and ISB was assessed by a questionnaire completed by patients' caregivers and records during hospitalization. Patients were then subdivided on the basis of the presence or absence of ISB. Of the 133 demented patients, 20 (15.0%) were reported to demonstrate ISB at home or during hospitalization. Patients with ISB had various types of dementia. There were no significant differences in patients with and without ISB in regard to age, age of onset, gender, educational level, or Mini-Mental State Examination scores. ISB is not unusual in dementia patients and can be found in different types of dementia. Medical care providers need to be trained to discuss sexual issues with caregivers and offer ideas and training to help cope with patients with ISB.

Mortality in geriatric psychiatric inpatients

OBJECTIVE

This study investigated the deaths of patients sixty-five and older on a psychiatric ward to determine the mortality rate, the characteristics of illness, and the cause of death.

METHODS

We analyzed the case record of patients sixty-five and older who had died during hospitalization on a psychiatric ward during a seventeen-year period. Case data was collected by review of chart records.

RESULTS

The mortality rate in the patients sixty-five and older was 18/1208 (1.5%). Eight of these eighteen patients died of pneumonia. Mortality in the acutely ill geropsychiatric inpatients was difficult to predict. Age, sex, and diagnosis did not predict mortality.

CONCLUSIONS

To reduce mortality, especially in male veterans, management of geropsychiatric patients should include early recognition of pneumonia symptoms, especially for patients with history of pulmonary disease.

Effects of outlet obstruction and its reversal on mitochondrial enzyme activity in rabbit urinary bladders

PURPOSE

This study investigated the effects of outlet obstruction and its reversal on mitochondrial enzyme activity in the rabbit urinary bladder.

MATERIALS AND METHODS

We induced mild bladder outlet obstruction in male New Zealand White rabbits. Following two weeks of obstruction, one group of animals (n = 6) was sacrificed, while outlet obstruction was relieved in three additional groups of animals, which were sacrificed one (n = 5), two (n = 5) and four (n = 5) weeks after relieving the obstruction. Seven sham operated rabbits served as controls. We extracted mitochondria from fresh detrusor and assayed activities of key mitochondrial enzymes in the citric acid cycle, citrate synthase and malate dehydrogenase, as well as those in the electron transport chain, succinate cytochrome c reductase, NADH-cytochrome c reductase and cytochrome c oxidase. With high performance liquid chromatography (HPLC) we determined the tissue content of phosphocreatine and the adenine nucleotides (ATP, ADP and AMP), which was used for calculating energy charge. Responses of detrusor strips to 500 microM bethanechol and 120 mM KCl provided the assessment of detrusor contractility.

RESULTS

Contractile response of the detrusor strips to bethanechol stimulation was significantly reduced by outlet obstruction, nevertheless, it recovered gradually toward the control level after the relief of outlet obstruction. Outlet obstruction reduced the detrusor content of phosphocreatine, ATP and energy charge. After relieving the obstruction, however, these recovered gradually, reaching control levels 4 weeks later. The activities of all assayed enzymes were reduced by two weeks of outlet obstruction. Relieving the obstruction restored enzyme activity gradually but at different rates for different enzymes. Activities of the citric acid cycle enzymes citrate synthase and malate dehydrogenase recovered and were similar to control levels four weeks after relief of the obstruction. Of the enzymes in the electron transport chain, NADH cytochrome reductase activity recovered most quickly by one week after relief of the obstruction. The activity of cytochrome c oxidase improved more slowly, but 4 weeks after relieving the obstruction it, also, was restored and was similar to the control level. Succinate cytochrome reductase activity remained lower than the control over the entire four weeks of recovery.

CONCLUSIONS

The close association between mitochondrial enzyme activity, energy metabolism and contractility of the detrusor indicates the important role of mitochondrial enzyme damage in decreasing energy production and impairing contractile function of the urinary bladders following outlet obstruction. Our findings also show that various mitochondrial enzymes exhibit different susceptibilities and reversibilities to pathological stress.

Softened endothracheal tube reduces the incidence and severity of epistaxis following nasotracheal intubation

BACKGROUND

Many complications were reported to be related with nasotracheal intubation. Various chemical or mechanical techniques have been proposed to decrease hemorrhage and trauma associated with nasotracheal intubation but the results remain controversial. We conducted a prospective, randomized, single-blind study to elucidate the effect of an endotracheal tube softened with warm water before use on the incidence and severity of epistaxis following nasotracheal intubation.

METHODS

Sixty-two healthy, (ASA class I or II) patients scheduled for elective surgery were randomly assigned into two groups. Patients in the treatment group were intubated with a softened endotracheal tube made possible by heating it in warm water while those in the control group were intubated with unsoftened (intact) tube. Epistaxis was evaluated immediately after intubation and its severity was graded as none, mild, moderate and severe. The use of Magill forceps and postoperative nasal morbidity were also recorded.

RESULTS

The total incidence of epistaxis in the "unsoftened" group was significantly higher than that of "softened" group (76.7% vs. 43.8%, P = 0.0002). The severity of nasal hemorrhage was also significantly lightened in the "softened" group. No technical difficulty was encountered in intubation with a softened endotracheal tube by prewarming. The morbidity referable to nasal intubation, however, did not differ in both groups.

CONCLUSIONS

In conclusion, our study shows that using an endotracheal tube softened by warm water could reduce the incidence and severity of epistaxis during the act of nasotracheal intubation. It is an effective way and worth a try.

The kinetics of IL-4 and IFN-gamma gene expression in mice after Trichosansin immunization

Trichosanthin (TCS) is a potent allergen to mice. According to our previous experiments, it could bring out the IgE response to ovabumin (OVA) if TCS was given one day before OVA immunization, while OVA alone could not induce IgE to it. In this work, the kinetics of interleukin 4(IL-4) and interferon gamma(IFN-gamma) gene expression in the mesenteric lymph node (MLN) of TCS-immunized mice was investigated using a semi-quantitative RT-PCR method. It indicated that TCS induced significant IL-4 gene expression and the peaks of IL4 gene expression were on day one after TCS immunization in both primary and secondary response. In contrast, the IFN-gamma gene expression was suppressed. Furthermore, the IL-4 gene expression in the secondary response was lower than that in the primary response. Thus the presence of IgE memory B cells were studied. Results showed that the amount of mature IgE mRNA arose significantly and rapidly one day after TCS restimulation, while in the MLN of the mice primed 30 days before and without boost, it was almost as the same amount of the unimmunized control. These findings suggest the existence of the IgE memory B cells in the mice after the primary TCS immunization.

Biochemical modulation of doxorubicin by high-dose tamoxifen in the treatment of advanced hepatocellular carcinoma

BACKGROUND/AIMS

In vitro data have indicated that tamoxifen (> 2.5 uM) significantly enhances the cytotoxic effect of doxorubicin in hepatocellular carcinoma (HCC) cells. This clinical study was conducted to examine whether tamoxifen, at a dose sufficient to result in a plasma concentration of more than 2.5 uM, may improve the therapeutic efficacy of doxorubicin in patients with advanced HCC.

METHODOLOGY

A prospective phase II study was conducted. Eligible patients had unresectable and non-embolizable HCC, objectively measurable tumors, adequate neogram with absolute granulocyte count > 2,000/mm3 and platelet count > 1 x 10/mm3, total serum bilirubin < 3.0 mg/dl, age > or = 75 year, and a Karnofsky performance status < or = 50%. The treatment included oral tamoxifen 40 mg/m2, q.i.d, Day 1 to 7, and intravenous doxorubicin 60 mg/m2, Day 4, repeated every 3 weeks.

RESULTS

Between May 1994 and December 1996, a total of 38 patients were enrolled in the study. Thirty-six patients were evaluable for tumor response and treatment-related toxicities. There were 32 men and 4 women, with a median age of 49 years. They received an average of 3.8 (range:1-12) courses of chemotherapy. ECOG (Eastern Cooperative Oncology Group) Grade 3-4 leucopenia and Grade 3-4 thrombocytopenia developed in 27.2% and 12.5% courses given, respectively. Gastrointestinal toxicity was generally mild. Three patients developed symptomatic cardiac toxicity. Twelve patients (33.3%, 95% confidence interval 17-51%) had achieved a partial remission (PR), with a median progression-free survival of 7 months. Median survivals of the responders and non-responders were 10 and 3 months, respectively (p<0.05). The median Karnofsky performance status of the responders improved from 74.0+/-6.3% to a post-chemotherapy value of 93.2+/-4.6% (p<0.05)

CONCLUSIONS

High dose tamoxifen appears to be an effective biochemical modulator of doxorubicin in the treatment of HCC. Prospective randomized phase III studies comparing doxorubicin alone versus doxorubicin plus high-dose tamoxifen are needed.

Hoarding behavior in dementia. A preliminary report

Hoarding behavior has been reported in several mental disorders and is occasionally reported by the caregivers of dementia patients. Such behavior may have adverse effects on the patients and increase the burden of the caregivers. This study was conducted to investigate the prevalence of hoarding behavior in patients with dementia and identify the characteristics and psychiatric symptoms associated with it. The sample was 133 dementia patients admitted to a geropsychiatric ward. Of the 133 dementia patients, 30 (22.6%) showed hoarding. Hoarding was found in various types of dementia. Patients with hoarding had a higher prevalence of repetitive behaviors, hyperphagia, and pilfering. Results suggested that hoarding behavior is a common symptom in dementia patients and a complex phenomenon. Better understanding of the underlying pathogenesis may highlight specific pharmacological or behavioral methods for treatment of the behavior.

Bcl-2 prevents topoisomerase II inhibitor GL331-induced apoptosis is mediated by down-regulation of poly(ADP-ribose)polymerase activity

Poly (ADP-ribose) polymerase (PARP), a nuclear enzyme responsible for DNA strand breaks, has been recently suggested to be crucial for apoptosis induced by a number chemotherapeutic drugs. In this study, we demonstrated that the PARP activity could be evidently elevated with a peak at 6 h when HL-60 cells were treated with a new anticancer drug GL331. Coincident with the peak of PARP activity, an apparent DNA fragmentation and apoptotic morphology were observed in cells treated with GL331. The subsequent apoptotic DNA fragmentation induced by GL331 could be completely blocked by transfecting cells with anti-sense PARP retroviral vector or by treating cells with PARP inhibitor, 3-aminobenzamide (3-AB). This blocking effect thus suggests that activation of PARP was critically involved in GL331-induced apoptosis. The fact that Bcl-2 has been found to antagonize cell death induced by a wide variety of agents, accounts for why we examined whether if Bcl-2 could antagonize GL331 effects. Interestingly, ectopic overexpression of Bcl-2 in either HL-60 or U937 cells caused in resistance towards GL331-elicited DNA fragmentation and cytotoxic effect. Additionally, Bcl-2 also attenuated the poly(ADP-ribosyl)ation of PARP itself as well as Histone H1 at the early period of drug treatment. However, Bcl-2 did not influence the extent of DNA strand breaks induced by GL331 in either control or Bcl-2-overexpressing cells. In addition, analysis of basal PARP activity in control and several Bcl-2 overexpressing clones revealed that Bcl-2 down-regulated PARP activity under the condition without DNA damages. Above findings suggest that poly(ADP-ribosyl)ation of nuclear targets is important for apoptosis induced by DNA-reactive anticancer drugs.

Serological characterization of the 3'-proximal encoded proteins of beet yellows closterovirus

The 3'-proximal open reading frames (ORFs) of beet yellows closterovirus, California isolate (BYV-CA), were sequenced and the expression of the corresponding proteins analyzed. The nucleotide sequence of ORF 5 (coding for p24) was most conserved compared with ORF 7 (coding for p20) and ORF 8 (coding for p21) among the isolates analyzed. Polyclonal antisera were produced to GST fusion proteins of p24, p20, and p21. Accumulation of p24, CP, p20 and p21 was studied in infected Tetragonia expansa plants and Chenopodium quinoa protoplasts. All four proteins were expressed in all tissues (old leaves, young leaves and stems), and most abundantly in young leaves. The subcellular localization of each protein in different tissues showed that compared with p24, CP and p21, p20 accumulated less in transfected protoplasts. Immunogold labeling in sugarbeet with p24 and CP antisera demonstrated co-localization of p24 and CP in vascular petiole tissues. In infectivity neutralization tests, antisera against p24 and CP greatly reduced transmission of BYV by viruliferous aphids compared with viruliferous aphids fed on preimmune serum or antiserum to p21.

A possible hydrolysis mechanism of beta-naphthyl acetate catalyzed by antibodies

The mechanism of ester hydrolysis has been extensively studied; however, the precise function of active-site residues in promoting catalysis is unclear. We describe here the structural models for the complex of a catalytic antibody Fv fragment with a phosphonate transition-state analogue, constructed by using gene cloning, sequencing and molecular modeling, mainly based on a known X-ray structure of a catalytic antibody. Hydrophobic and electrostatic analyses of the Fv/analog and Fv/substrate interaction suggest the hydrolysis mechanism: Tyr L91 and Tyr H97 play important roles to stabilize the beta-naphthyl group of hapten through pi-stack; His H35 donates a pair of free electrons at the atom NE2 to an active water and let it to be a partial hydroxide, which attacks the carbon atom of the carbonyl group of the substrate. Both His H35 and Arg L96 can form hydrogen bonds and stabilize the anionic tetrahedral intermediate formed during turnover. This mechanism emphasizes that an active water bridge may be formed during hydrolysis process.

Chromosomal localization of the murine RFC-1 gene encoding a folate transporter and its amplification in an antifolate resistant variant overproducing the transporter

A variant of the L1210 cell (L1210/R83) selected in the presence of the lipophilic antifolate, metoprine, and a concentration of the natural diastereoisomer of 5-formyltetrahydrofolate, lL5CHO-folateH4, suboptimum for growth exhibited a 35-fold increase compared to parental L1210 cells in one-carbon, reduced folate transport. This was evidenced by the increase in Vmax for [3H]MTX (methotrexate) influx and a commensurate increase in the amount of the 46 kilodalton (kDa) transport protein and reduced folate carrier (RFC-1) mRNA. The variant is resistant to lipophilic antifolates, but shows collateral sensitivity to classical folate analogues. Karyotype analysis of L1210/R83 cells revealed the presence of several new chromosome abnormalities. One of these was a large, submetacentric marker chromosome comprising a normal #10 and a longer, abnormally banded arm of uncertain origin which exhibited an interstitial, palely staining, HSR-like segment. The results of Southern and Northern blotting showed that the RFC-1 gene copy number and RNA transcript level were markedly increased (30-35 fold) in L1210/R83 cells. Fluorescence in situ hybridization (FISH) analysis revealed that the HSR-like segment in these cells was the site of amplified RFC-1 genes. Independent revertant subclones, obtained following growth in the absence of selection pressure, showed four- to 12-fold decreases in [3H]MTX influx Vmax and in amount of NHS (N-hydroxysuccinimide)-[3H]MTX affinity labeled one-carbon, reduced folate transporter compared to L1210/R83 cells. RFC-1 gene copy number also decreased, and the mean length of the HSR in these revertants declined 1.6- to 5-fold. Based upon genomic nucleotide sequencing, the RFC-1 gene in the normal mouse genome was localized to chromosome 10 in close association with the alpha 1 (Col18a1) collagen gene at 10B3(locus 41cM). The close association of these genes was confirmed by other data showing that the alpha 1 collagen gene was co-amplified in L1210/R83 cells. These results document the amplification at the site of a putative HSR in an L1210 cell variant of the RFC-1 gene regulating expression of the one-carbon, reduced folate transporter.

FLD interacts with genes that affect different developmental phase transitions to regulate Arabidopsis shoot development

A new fld mutant allele, fld-2, which significantly delayed flowering, was isolated and characterized in Arabidopsis thaliana. Even under long-day conditions after more than 100 days in the greenhouse, the majority of fld-2 mutant plants had not bolted. In addition, mutant inflorescences produced more than 10 co-florescences that were subtended by a high number of rosette-like leaves before giving rise to flowers. The late-flowering phenotype of the fld-2 mutation could be partially overcome by both vernalization and GA treatment but it was not influenced by 5-azaC treatment. Phenotypic analyses of double mutants indicated that fld-2 is epistatic to early flowering mutants elf1, elf2 and elf3. In addition, fld-2 could enhance vegetative characteristics in embryonic flower 1 (emf1) mutants by causing many small sessile leaves in fld-2 emf1 double mutants. The relief of the terminal flower 1 (tfl1) mutant phenotype in fld-2 tfl1 double mutants, and the enhancement of leafy (lfy) and apetala1 (ap1) mutant phenotypes in fld-2 lfy and fld-2 ap1 double mutants, suggest that FLD is also likely to be involved in the floral transition. Our results strongly suggest that the FLD gene plays a key role in regulating the reproductive competence of the shoot and results in different developmental phase transitions in Arabidopsis.

Inhibition of fos-jun-DNA complex formation by dihydroguaiaretic acid and in vitro cytotoxic effects on cancer cells

The effect of dihydroguaiaretic acid (DHGA), isolated from the aryls of Myristica fragrans, on the transcription factor (fos-jun dimer) action was investigated via in vitro assay. DHGA showed an inhibitory effect against the complex formation of the fos-jun dimer and the DNA consensus sequence with an IC50 value of 0.21 micromol. Nordihydroguaiaretic acid (NDGA) and curcumin also inhibited fos-jun dimer action showing IC50 values of 7.9 and 6.9 nmol, respectively. DHGA and NDGA suppressed leukemia, lung cancer and colon cancer in an in vitro bioassay. The in vitro experiment suggested that inhibition of fos-jun-DNA complex formation could be due to the direct interference of fos-jun dimer binding onto the DNA consensus sequence by NDGA and curcumin.

STAT3 complements defects in an interferon-resistant cell line: evidence for an essential role for STAT3 in interferon signaling and biological activities

STAT proteins play critical roles in the signal transduction pathways for various cytokines. The type I interferons (IFNalpha/beta) promote the DNA-binding activity of the transcription factors STAT1, STAT2, and STAT3. Although the requirement for STAT1 and STAT2 in IFNalpha/beta signaling and action is well documented, the biological importance of STAT3 to IFN action has not yet been addressed. We found that STAT3 plays a critical role in signal transduction by IFNalpha/beta. A human cell line that is resistant to the antiviral and antiproliferative activities of IFN but is still IFN-responsive by virtue of STAT1 and STAT2 activation was found to be defective in STAT3 activation and in induction of NF-kappaB DNA-binding activity. Expression of STAT3 in these resistant cells complemented these signaling defects and also markedly increased cellular sensitivity to the antiviral and antiproliferative effects of IFN. Because STAT3 is involved in the induction of NF-kappaB DNA-binding activity and in the induction of antiviral and antiproliferative activity, our results place STAT3 as an important upstream element in type I IFN signal transduction and in the induction of biological activities. Therefore, our results indicate that STAT1 and STAT2 are not the only STATs required for the expression of the key biological activities of IFNalpha/beta.

Crystallization and preliminary X-ray studies of hORF6, a novel human antioxidant enzyme

HORF6 is a member of the novel antioxidant enzyme family found in humans. A recombinant form of hORF6 expressed and purified from E. coli has been crystallized by the hanging-drop method using various PEG's as precipitating agents. HORF6 crystallizes in two different monoclinic space groups, P21 and C2. The P21 crystals have unit-cell dimensions of a = 47.85, b = 75.17, c = 63.30 A and beta = 110.21 degrees and contain two monomers per asymmetric unit, while the C2 crystals have unit-cell dimensions of a = 165.27, b = 95.44, c = 166.44 A and beta = 128.97 degrees and contain more than six monomers per asymmetric unit. The P21 crystals with the smaller unit cell diffract X-rays better and behave well for the X-ray analysis. A native data set from a single crystal of the P21 space group gas been collected to 2.0 A resolution.

Crystal structure of a novel human peroxidase enzyme at 2.0 A resolution

Hydrogen peroxide (H2O2) has been implicated recently as an intracellular messenger that affects cellular processes including protein phosphorylation, transcription and apoptosis. A set of novel peroxidases, named peroxiredoxins (Prx), regulate the intracellular concentration of H2O2 by reducing it in the presence of an appropriate electron donor. The crystal structure of a human Prx enzyme, hORF6, reveals that the protein contains two discrete domains and forms a dimer. The N-terminal domain has a thioredoxin fold and the C-terminal domain is used for dimerization. The active site cysteine (Cys 47), which exists as cysteine-sulfenic acid in the crystal, is located at the bottom of a relatively narrow pocket. The positively charged environment surrounding Cys 47 accounts for the peroxidase activity of the enzyme, which contains no redox cofactors.

Differences in activity between alpha and beta type I interferons explored by mutational analysis

Type I interferon (IFN) subtypes alpha and beta share a common multicomponent, cell surface receptor and elicit a similar range of biological responses, including antiviral, antiproliferative, and immunomodulatory activities. However, alpha and beta IFNs exhibit key differences in several biological properties. For example, IFN-beta, but not IFN-alpha, induces the association of tyrosine-phosphorylated receptor components ifnar1 and ifnar2, and has activity in cells lacking the IFN receptor-associated, Janus kinase tyk2. To define the structural basis for these functional differences we produced human IFN-beta with point mutations and compared them to wild-type IFN-beta in assays that distinguish alpha and beta IFN subtypes. IFN-beta mutants with charged residues (N86K, N86E, or Y92D) introduced at two positions in the C helix lost the ability to induce the association of tyrosine-phosphorylated receptor chains and had reduced activity on tyk2-deficient cells. The combination of negatively charged residues N86E and Y92D (homologous with IFN-alpha8) increased the cross-species activity of the mutant IFN-betas on bovine cells to a level comparable to that of human IFN-alphas. In contrast, point mutations in the AB loop and D helix had no significant effect on these subtype-specific activities. A subset of these latter mutations did, however, reduce activity in a manner analogous to IFN-alpha mutations. The effects of these mutations on IFN-beta activity are discussed in the context of a family of related ligands acting through a common receptor and signaling pathway.

Striatal dopamine dynamics are altered following an intranigral infusion of iron in adult rats

In vivo electrochemical detection was employed to examine iron-induced oxidative injury on dopamine dynamics in the nigrostriatal system of urethane-anesthetized rats. Seven days after an intranigral infusion of iron, oxidative stress was confirmed by an elevated lipid peroxidation in lesioned substantia nigra (SN). Local application of potassium (K+) evoked dopamine releases from the dopamine-containing nerve terminals in the striatum. Both amplitude and rate of clearance (Tc) of evoked dopamine releases were lower in striatum with lesioned SN; however, the time course parameters of dopamine release in the lesioned group were not different from those of the intact group, indicating a reduction in dopamine clearance. Indeed, iron-induced oxidative stress attenuated the effect of nomifensine, a high-affinity dopamine uptake blocker, on dopamine clearance. In striatum with intact SN, the amplitude and time course parameters of signals by exogenous dopamine were increased and Tc was decreased by nomifensine. In contrast, nomifensine did not significantly alter the dopamine signals of the lesioned group. Taken together, in addition to the increased lipid peroxidation in SN, our in vivo electrochemical data demonstrates that iron-induced oxidative injury attenuates K+-evoked dopamine release and dopamine uptake in the ipsilateral striatum. The diminished nomifensine effect implies a lack of high-affinity dopamine uptake sites.

EMF genes interact with late-flowering genes to regulate Arabidopsis shoot development

To investigate the genetic mechanisms regulating the transition from vegetative to reproductive phase in Arabidopsis, double mutants between two embryonic flower (emf) and 12 different late-flowering mutants were constructed and analyzed. Double mutants in all combinations displayed the emf phenotypes without forming rosettes during early development; however, clear variations between different double mutants were observed during late development. fwa significantly enhanced the vegetative property of both emf mutants by producing a high number of sessile leaves without any further reproductive growth in emf1 fwa double mutants. It also produced numerous leaf-like flower structures similar to those in leafy ap1 double mutant in emf2 fwa double mutants. Nine late-flowering mutants, ft, fca, ld, fd, fpa, fe, fy, fha, and fve, caused different degrees of increase in the number of sessile leaves, the size of inflorescence, and the number of flowers only in weak emf1 and emf2 mutant alleles background. Two late-flowering mutants, co and gi, however, had no effect on either emf1 and emf2 mutant alleles in double mutants. Our results suggest that FWA function in distinct pathways from both EMF genes to regulate flower competence by activating genes which specify floral meristem identity. CO and GI negatively regulate both EMF genes, whereas the other nine late-flowering genes may interact with EMF genes directly or indirectly to regulate shoot maturation in Arabidopsis.

Resistance and Susceptibility of Arabidopsis thaliana to Bacterial Wilt Caused by Ralstonia solanacearum

ABSTRACT Tomato bacterial wilt caused by Ralstonia solanacearum is a model system for studying plant-bacterial interactions, because it is genetically one of the best characterized plant diseases. We demonstrate here that four different strains of R. solanacearum, two from radishes (Rd4 and Rd15) and two from tomato (Ps21 and Ps95), can infect 27 different ecotypes of Arabidopsis thaliana, causing different responses. All ecotypes tested were highly susceptible to strain Rd15, which caused symptoms similar to those observed in tomato plants. For example, leaf drooping and discoloration developed just 3 days after inoculation, and plants completely wilted within 1 week. Strains Rd4 and Ps95 were less infectious than Rd15. With these two strains, a variety of disease responses were observed among different ecotypes at 2 weeks after inoculation; both susceptible and resistant ecotypes of A. thaliana were identified. Ps21 was the least infectious of the four strains and caused almost no symptoms in any of the ecotypes of Arabidopsis tested. Direct bacterial isolation and plant skeleton hybridization analysis from infected plants indicated that bacterial colonization was correlated with the severity of symptoms. Growth of bacteria was limited to the infection site in resistant plants, whereas the bacteria spread throughout susceptible plants by 1 week after inoculation.