Clinical outcome and treatment sequences of patients with advanced pancreatic cancer treated with contemporary chemotherapy protocols

Introduction Systemic therapy is firmly established in patients with advanced or metastatic pancreatic ductal adenocarcinoma (PDAC). Clinical efficacy is still modest and options are limited. Combination therapy protocols such as FOLFIRINOX and gemcitabine/nab-paclitaxel (Gem/NP) define standard-of-care. Patients may receive a sequence of both regimens as first- and second-line palliative treatment. However, there is no guidance regarding a preferred order. Methods Retrospective analysis of clinical characteristics, treatment trajectories and outcomes of patients with advanced PDAC treated at the West German Cancer Center Essen from 2014 to 2020 to inform treatment decisions with respect to predictive factors, impact of chemotherapy regimen sequence and maintenance treatment. Results We identified 170 patients with available follow-up. Of those, 160 (94.1%) pts received palliative CTX for primary metastatic, locally advanced or recurrent PDAC. Median PFS upon first palliative chemotherapy was 4.1 (3.1 - 5.9) months. First-line FOLFIRINOX associated with superior PFS (median 6.3 months) and OS (9.7 months, HR 0.7, p=0.03) as compared to gemcitabine/nab-paclitaxel or other regimens (PFS 3.0, OS 6.9 months). However, OS benefit of first-line FOLFIRINOX was lost in patients who received at least two treatment lines (median OS 12.1 vs. 13.1 months, p=0.43). A landmark analysis of patients with clinical benefit (defined at CR/PR/SD for at least 20 weeks) upon first-line therapy revealed improved OS (HR 0.53, p=0.02) for patients receiving continued deescalated maintenance therapy. Second-line regimens resulted in similar PFS (overall log-rank p=0.92, median PFS2 2.3 (1.8-2.9), per-regimen median between 1.8 and 3.9 months). A previously established systemic inflammation score proved to be strongly prognostic and allowed identification of a patient subgroup with dismal prognosis (OS 2.9 vs. 11.4 months, HR 5.23, p<0.001), independent of other prognostic factors and with no relevant interaction with the choice of first-line regimen. Conclusion In this real world population of PDAC patients treated with contemporary combination chemotherapies, a positive impact of first line FOLFIRINOX was only observed when no second or further line treatment was administered. Intensity-reduced maintenance therapy may lead to superior survival.

Peri- and intraoperative EEG signatures in newborns and infants

OBJECTIVE

The electroencephalographic derived indices have been developed for adult patients, however these monitors have not been validated for infants.

METHODS

Frontal EEGs were recorded in 115 infants aged <1 year [0-3-months (N = 27), 4-6-months (N = 30), 7-9-months (N = 29) and 10-12-months (N = 29)] who received general anaesthesia with sevoflurane. Total power (µV²) and relative β-, α-, θ-, δ-power (%) were analyzed. Additionally, in 20 EEGs event marker were added (baseline, loss of consciousness, intraoperative situation, extubation) to assess perioperative EEG dynamics.

RESULTS

Newborns show a mean relative δ-power at 80% in intraoperative EEG compared to infants (10-12 months) showing 47.5%. Relative β-power and α-power are low in newborns (mean 3.2% and 4.6%; respectively), with a marked increase in the older infants (4-6 months) (mean 10.9% and 14.4%; respectively). EEG dynamic in newborns from baseline (relative δ-power of 88%) to the intraoperative situation (80.5%) are discrete. In contrast infants >6-months have a strong reduction of relative δ-power from baseline to the intraoperative situation, which corresponds to an increase of faster frequencies.

CONCLUSIONS

Age dependent perioperative EEG signatures can be demonstrated in infants younger than one year.

SIGNIFICANCE

We demonstrate significant differences in EEG readouts between newborns and infants which questions our monitoring systems in paediatric anaesthesia.

Galectin-3 is inversely associated with cardiorespiratory fitness in the general population

Funding Acknowledgements

Type of funding sources: None.

Introduction

Low cardiorespiratory fitness (CRF) is associated with high mortality and morbidity. Galectin-3 (Gal-3) is a prognostic biomarker for fibrosis, different cancers, renal impairment and, in particular, for heart failure. Further, higher Gal-3 levels are associated with increased cardiovascular mortality. Whether Gal-3 is related with the protective effects of a high CRF is unclear.

Purpose

The present study examined the relation between Gal-3 and CRF as determined by body weight adjusted peak oxygen uptake (VO2peak/kg), oxygen uptake at the anaerobic threshold (VO2@AT) and maximal workload (Wmax).

Methods

We used data of the population-based Study of Health in Pomerania (SHIP-TREND) from Northeast Germany. A total of n = 1,483 participants with a median age of 49 (IQR: 39 – 59 years, male 48%) were included in the analysis. CRF parameters were measured using standardized cardiopulmonary exercise testing on a bicycle ergometer. Plasma galectin-3 concentrations were determined using a quantitative sandwich enzyme immunoassay. Individuals with left ventricular ejection fraction &lt; 40%, previous myocardial infarction, atrial fibrillation, chronic lung disease, severe renal disease (eGFR &lt; 30 ml/min/mm2), a history of cancer, and extreme values for Gal-3 were excluded. Linear regression models adjusted for age, sex and lean mass were used to analyze the association between Gal-3 and CRF.

Results

A one ml/min/kg greater VO2peak was related to a 0.32 ng/ml (95% confidence interval [CI] -0.45 to -0.18, p &lt;.001) lower Gal-3. Further, a one Watt larger power output was also associated with a 1.32 ng/ml (95% CI -2.10 to – 0.54, p &lt;.001) lesser Gal-3. VO2@AT was not related to Gal-3 (β: -3.31 95% CI -8.68 to 2.05, p = .23).

Conclusions

In the general population Gal-3 is inversely associated with CRF. Further studies should investigate whether lower Gal-3, beyond its importance as a biomarker for heart disease, may even play a role in the protective effect of the CRF.

The association between S1P and vascular disease markers in the general population

Funding Acknowledgements

Type of funding sources: None.

Introduction 

Sphingosine-1-phosphate (S1P) is a lipid mediator of the immune system and vascular bed. However, cross-sectional analyses of S1P and parameters of vascular health in the population are sparse.

Purpose 

We explored the relation between S1P concentrations and several parameters of vascular health, i.e. ankle-brachial index (ABI), carotid intima-media thickness (cIMT), presence of carotid atherosclerotic plaques/stenosis, brachial artery flow-mediated dilation (FMD) as well as aortic wall thickness (AWT).

Methods

S1P was measured by liquid chromatography-tandem mass spectrometry in the population-based Study of Health in Pomerania (SHIP-TREND-0). ABI was calculated as the ratio of systolic blood pressure in arms and ankles. For cIMT, the distance between the lumen-intima and media-adventitia interfaces in longitudinal scans were measured. Carotid plaques were defined as a focal protrusion of the carotid vessel wall. Carotid stenosis was assessed with Doppler ultrasonography. FMD was evaluated by measuring the increase in brachial artery diameter after transient forearm ischemia. AWT was assessed by Magnetic Resonance Imaging.  Subjects with cancer, severe renal insufficiency, previous myocardial infarction and extreme values for S1P (&lt; 1st and &gt; 99th percentile) were excluded. Sex stratified linear regression models adjusted for age, smoking, waist-to-hip ratio and platelets were used to assess the relation between S1P and vascular disease parameters.

Results

A total of n = 3,643 participants (48% male, median age 51, 25th and 75th percentile 39 and 63 years) could be included in the analyses. The median S1P concentration was 0.788 µM (25th and 75th percentile 0.679 and 0.906, respectively). In men a 1 standard deviation higher S1P was associated with a significantly greater cIMT (β: 0.0057 95% confidence interval [CI]: 0.00027 to 0.0112 mm; p = 0.0396) and a lower ABI (β: -0.0090 (95% confidence interval [CI]: -0.0153 to -0.0029; p = 0.0038. In women S1P was significantly associated with cIMT (β: 0.0044 95% confidence interval [CI]: 0.0001 to 0.0086 mm; p = 0.0445) while no significant association was found for the relation of S1P with ABI. For both men and women S1P was not associated with FMD, the presence of carotid plaques/stenosis and AWT.

Conclusions

We found that S1P concentrations were positively related to a thicker cIMT in both sexes and lower ABI values in men. There was no association of S1P with any of the other vascular markers of interest. Future studies need to validate our results in other populations.

Combined systemic inflammation score (SIS) correlates with prognosis in patients with advanced pancreatic cancer receiving palliative chemotherapy

PURPOSE

The prognosis of patients with advanced pancreatic ductal adenocarcinoma (PDAC) remains dismal. New cytotoxic agents such as nab-paclitaxel and liposomal irinotecan (nal-Iri) have extended the armamentarium of therapeutic options in the last years. Nowadays, sequential therapeutic strategies with moderately toxic chemotherapeutic protocols can be administered to the patients. However, prognostic and predictive biomarkers are still missing to identify those patients, which profit most from a "continuum of care" concept rather than receiving intensive first-line protocols such as FOLFIRINOX. To this end, we retrospectively evaluated the impact of the systemic inflammation as one essential hallmark of cancer in patients with advanced PDAC treated with sequential systemic.

METHODS

A cohort of 193 PDAC patients treated at our center from January 2005 to August 2011 were retrospectively evaluated for the following systemic inflammatory response (SIR) markers: neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR) C-reactive protein (CRP), and the modified Glasgow Prognostic Score (mGPS). SIR markers were correlated with clinico-pathological findings, response to chemotherapy and overall survival (OS) using Kaplan-Meier curves and Cox proportional models.

RESULTS

All evaluated SIR markers were significantly associated with OS in patients with metastatic disease but not in patients with locally advanced PDAC. Interestingly, all SIR markers were only prognostic in patients not receiving antibiotics as surrogate marker for systemic bacterial infections. Based on the evaluated SIR markers, we propose a new Systemic Inflammation Score (SIS), which significantly correlated with reduced OS (HR: 3.418 (1.802-6.488, p < 0.001)) and the likelihood of receiving further-line systemic therapies (p = 0.028).

CONCLUSION

Routinely assessed SIR biomarkers have potential to support therapeutic decision making in patients with metastatic PDAC.

Long-term outcome of patients with advanced pancreatic cancer treated with sequential chemotherapies before the era of modern combination therapy protocols

INTRODUCTION

Patients (pts) with locally advanced (LAPC) or metastatic pancreatic ductal adenocarcinoma (mPDAC) have a dismal prognosis. Recently, new combination chemotherapies such as FOLFIRINOX and nab-paclitaxel/gemcitabine have demonstrated superiority over gemcitabine monotherapy. However, a substantial proportion of pts cannot tolerate these intensive front-line protocols. Moreover, the long-term superiority of multiagent protocols over less intensive strategies remains to be shown. To provide a benchmark for future studies, we analyzed the outcome of patients with LAPC or mPDAC treated at the West German Cancer Center before the FOLFIRINOX/nab-paclitaxel + gemcitabine era.

METHODS

This retrospective analysis included 201 consecutive pts with LAPC and mPDAC treated between 2007 and 2011. Efficacy parameters were correlated with type of chemotherapy, number of treatment lines and clinicopathological parameters.

RESULTS

Gemcitabine monotherapy was given as first-line therapy in 51.1%, whereas 48.9% received combination chemotherapies such as gemcitabine/oxaliplatin or FOLFOX. Patients received a median of two lines of treatment, with 54.8% receiving second-line and 37.9% receiving third- and further-line therapies. There was no significant difference between gemcitabine monotherapy and combination therapies. Despite moderate activity of first-line treatment, median overall survival for LAPC was 11.3 months and 8.7 months for mPDAC. Multivariate analysis identified age and number of treatment lines as prognostic markers.

CONCLUSION

The long-term outcome of unselected pts with LAPC and mPDAC treated before the introduction of aggressive multiagent chemotherapy protocols compares favorably with the results of contemporary benchmark trials. This suggests a multifactorial benefit from interdisciplinary care provided over sequential treatment lines at high volume expert centers.

Parent-reported attention-deficit hyperactivity disorder and subtypes of conduct disorder as risk factor of recidivism in detained male adolescents

OBJECTIVE

Parents are considered to be crucial informants in child psychiatry, particularly for disorders in which age of onset is included in the diagnostic criteria. In detained adolescents, however, parents all too often are difficult to reach or reluctant to cooperate. The clinical relevance of gathering parental information in this context should therefore be demonstrated. This study examines if parent reports of attention-deficit-hyperactivity disorder (ADHD) and age of onset subtypes of conduct disorder (CD) predict official criminal recidivism.

METHOD

Participants were 110 detained male adolescents from all three Youth Detention Centers in Flanders. Between January 2005 and February 2007, both youth and a parent were interviewed with the Diagnostic Interview Schedule for Children Version IV. Two to 4 years later, information on criminal recidivism was retrieved.

RESULTS

Youth self-reported ADHD and CD (subtypes) were not related with recidivism. Parent-reported ADHD, CD and childhood-onset CD predicted serious property recidivism, while parent-reported adolescent-onset CD predicted future violent arrests. In reverse, childhood-onset CD as reported by parents was negatively associated with violent recidivism.

CONCLUSION

Obtaining parental diagnostic information in delinquent adolescents is crucial for predicting recidivism. This finding emphasizes the need of including parents when studying mental disorder in detained adolescents.

Transitions between oscillatory modes in a glycolytic model system

A glycolytic model system consisting of the enzymes phosphofructokinase (EC 2.7.1.11) and pyruvate kinase (EC 2.7.1.40) is analyzed when subject to periodic substrate addition. The calculations are performed by using detailed rate laws that have been derived for the enzymes of Escherichia coli. Due to linear relationships between the metabolite concentrations, the numerical solutions can be displayed inside a trapezium, so that the concentrations of four different metabolites are indicated along the trapezium edges. The analysis reveals a rich variety of time patterns, corresponding to different periodic, quasiperiodic, and chaotic attractors. These patterns undergo complex hysteresis loops when bifurcation parameters are slowly changed-for example, by modulating the input amplitude. By using this technique up to four attractors coexisting in phase space are found. The time patterns corresponding to coexisting attractors can be switched into one another by triggering the system with short substrate pulses. Furthermore, conditions exist at which the triggering is autonomous-i.e., self-sustained (intermittent) switchings occur. The time between these switchings can be set externally by the value of the input amplitude. For conditions in which the periods of the oscillations are in the order of minutes, the self-sustained switching-which modulates these oscillations-can be in the order of hours.

147. MOLECULAR CHARACTERIZATION OF RENIN - ANGIOTENSIN SYSTEM COMPONENTS IN HUMAN INTRAUTERINE TISSUES AND FETAL MEMBRANES FROM VAGINAL DELIVERY AND CAESAREAN SECTION

The expression of the (pro)renin receptor (ATP6AP2) in late gestational human tissues suggests that the prorenin-angiotensin system (RAS) might influence pregnancy outcome. Here w e characterized the RAS in term fetal membranes (amnion and chorion), decidua and placenta (n = 38) from women undergoing elective cesarean section (non-labouring) or following spontaneous delivery (after labour), and myometrium (n = 16) from elective or emergency cesarean (labouring) deliveries. RT-qPCR was used to quantify prorenin (REN), AGT, ACE, ACE2, AGTR1, AGTR2, ATP6AP2 and MAS1 mRNAs, and immunohistochemistry was used to localize prorenin, AGT, ACE, ACE2 and AGTR1 proteins. In myometrium, mRNAs for downstream signalling proteins (ZBTB16, TGFB1 and PTGS2) were also measured. ACE and AGT mRNA levels were higher in labouring myometrium (P < 0.05), consistent with elevated production of angiotensin II (Ang II), which, by the upregulation of PTGS2 occurring in labour (P = 0.022), could influence labour. In amnion, expression of all RAS component mRNAs, except ATP6AP2, was low. After labour amnion showed lower ACE (P = 0.014) and higher AGTR2 (P = 0.01) mRNA levels. In decidua, RAS components other than AGTR1 and AGTR2 were abundant. Amnion and chorion exhibited higher immunostaining of AGT and prorenin than expected from their low mRNA levels, suggesting that these proteins could have been originated from decidua, where the cognate genes are more active. In placenta, prorenin and AGT were localized to syncytiotrophoblasts and ACE was localized to fetal capillary endothelial cells, while ACE2 distribution was diffuse. AGTR1 mRNA and protein expression was high in the placenta. We propose that ACE in fetal vessels could contribute Ang II to the fetus, while ACE2 in syncytiotrophoblasts might convert placental or maternal circulating Ang II to angiotensin-(1–7), which might then be supplied to the maternal bloodstream. In conclusion, the abundance and distribution of intrauterine RAS components suggest diverse roles for this local RAS in pregnancy.

Properties of strange attractors in yeast glycolysis

The properties of periodic and aperiodic glycolytic oscillations observed in yeast extracts under sinusoidal glucose input were analyzed by the following methods. (1) Spectral analysis, rendering sharp peaks for periodic responses and enhanced broad-band noise for aperiodic oscillations. (2) Phase plane analysis, leading to closed and to open trajectories for periodic and aperiodic oscillations, respectively. (3) Rotation of a phase plane proportionally to time, revealing strange attractors associated with the aperiodic oscillations. (4) Stroboscopic plot on the phase plane, showing that the strange attractors follow a stretch-fold-press process, if the stroboscoping phase is varied. (5) Stroboscopic transfer plot, admitting a period of three transfer processes and thus implying chaos according to the Li-Yorke theorem. (6) Determination of the rate of information production by differentiation of the transfer plot, yielding approx. 0.21 bits per min for the chaotically glycolyzing yeast extract.

Efficient gene delivery with serum into human cancer cells using targeted anionic liposomes

Success of human gene therapy depends upon the development of delivery vehicles or vectors, which can selectively deliver therapeutic genes to target cells with efficiency and safety. Previous studies have shown an efficient, systemic trans-gene expression in many cell lines (in vitro) by using an anionic liposomal vector, based on the composition of retroviral envelopes (artificial viral envelopes, AVEs). The AVE-liposomes and their complexes with plasmid (DNA) were characterized according to zeta potential measurements and transmission electron microscopy (TEM). We successfully demonstrated that AVE liposomes, dispersed in 10% serum-containing growth medium, efficiently delivered plasmid DNA to HuH-7 (human hepatoma cell line) cells. We assessed the utility of liver-targeted vesicles as a drug/gene delivery system for the treatment of liver diseases. We found that small unilamellar AVE vesicles containing 15 mol% digalactosyl diglyceride (DGDG) are efficiently targeted to the liver via the hepatic asialoglycoprotein receptor.

Oscillations and turbulence induced by an activating agent in an active medium

An excitable Belousov-Zhabotinsky reagent becomes oscillatory above a threshold of methanol concentration [Me]. The oscillation period decreases with increasing [Me]. A model describes these observations quantitatively. In a spatiotemporal setup, a [Me] gradient causes waves with spatially varying properties; this leads to wave breaks that end up in turbulence, both in experiments and in simulations with partial differential equations.

A U-rich element in the 5' untranslated region is necessary for the translation of p27 mRNA

Increased translation of p27 mRNA correlates with withdrawal of cells from the cell cycle. This raised the possibility that antimitogenic signals might mediate their effects on p27 expression by altering complexes that formed on p27 mRNA, regulating its translation. In this report, we identify a U-rich sequence in the 5' untranslated region (5'UTR) of p27 mRNA that is necessary for efficient translation in proliferating and nonproliferating cells. We show that a number of factors bind to the 5'UTR in vitro in a manner dependent on the U-rich element, and their availability in the cytosol is controlled in a growth- and cell cycle-dependent fashion. One of these factors is HuR, a protein previously implicated in mRNA stability, transport, and translation. Another is hnRNP C1 and C2, proteins implicated in mRNA processing and the translation of a specific subset of mRNAs expressed in differentiated cells. In lovastatin-treated MDA468 cells, the mobility of the associated hnRNP C1 and C2 proteins changed, and this correlated with increased p27 expression. Together, these data suggest that the U-rich dependent RNP complex on the 5'UTR may regulate the translation of p27 mRNA and may be a target of antimitogenic signals.

Intermingled basins due to finite accuracy

We investigate numerically first a chaotic map interrupted by two small neighborhoods, each containing an attracting point, and secondly a periodically tilted box within which disorderly colliding disks can reach different attracting configurations, due to dissipation. For finite, arbitrarily small accuracy, both systems have basins of attraction that are indistinguishable from intermingled basins: any neighborhood of a point in phase space leading to one attractor contains points leading to the other attractor. A bifurcation destabilizing the fixed points or the disk configurations causes on-off intermittency; the disks then alternate between a "frozen" and a gaslike state.

Swirling granular solidlike clusters

Experiments and three-dimensional numerical simulations are presented to elucidate the dynamics of granular material in a cylindrical dish driven by a horizontal, periodic motion. The following phenomena are obtained both in the experiments and in the simulations: First, for large particle numbers N the particles describe hypocycloidal trajectories. In this state the particles are embedded in a solidlike cluster ("pancake") which counter-rotates with respect to the external driving (reptation). Self-organization within the cluster occurs such that the probability distribution of the particles consists of concentric rings. Second, the system undergoes phase transitions. These can be identified by changes of the quantity dE(kin)/dN (E(kin) is the mean kinetic energy) between zero (rotation), positive (reptation), and negative values (appearance of the totality of concentric rings).

Riddled-like basins of transient chaos

The set of initial conditions leading to transient chaos in the neighborhood of a crisis is shown to display riddled-like behavior for finite, arbitrarily small accuracy. Calculations are performed with the logistic equation, as well as with an experimentally verifiable, quantitative description of a chemical reaction. Limitations in computational or experimental accuracy make the apparent riddling of initial conditions a phenomenon that is indistinguishable from riddled basins.

Shell structures with "magic numbers" of spheres in a swirled dish

Molecular dynamic simulations of a low number N< or = 54 of spheres in a swirled dish yield solid-like shell structures with stable rings. In contrast to known granular media, solidification occurs only at singular values of N: 7, 8, 12, 14, 19, 21, 30, 37, 40. Otherwise, we obtain intermittent switching of particles between rings -- the average switching time scaling exponentially with a control parameter -- or fluid-like disorder. Stable shell structures can be classified by particular geometrical arrangements (one-centered hexagonal, one-centered "quasicircular," three centered, and four centered).

Characterization of the HSD17B4 gene: D-specific multifunctional protein 2/17beta-hydroxysteroid dehydrogenase IV

The HSD17B4 gene codes for a 80 kDa multifunctional enzyme containing three distinct functional domains and is localized in peroxisomes. The N-terminal part exhibits 3-hydroxyacyl-CoA dehydrogenase and 17beta-hydroxysteroid dehydrogenase activity whereas the central part shows enoyl-CoA hydratase activity. The carboxy-terminal part of the protein has sterol-carrier-protein activity. The protein is widely expressed, however in several tissues like brain, uterus and lung its expression is limited to specific cells like Purkinje cells or luminal epithelium. The HSD17B4 gene consist of 24 exons and 23 introns with classical intron-exon junctions spanning more than 100 kbp. The importance of the HSD17B4 protein is stressed by the identification of patients with severe clinical abnormalities due to mutations in the HSD17B4 gene. We have now checked the consequences of one frequent mutation, G16 S, which results in inactivation of the enzyme due to loss of interaction with NAD+.

Peroxisome targeting of porcine 17beta-hydroxysteroid dehydrogenase type IV/D-specific multifunctional protein 2 is mediated by its C-terminal tripeptide AKI

The product of the porcine HSD17B4 gene is a peroxisomal 80 kDa polypeptide containing three functionally distinct domains. The N-terminal part reveals activities of 17beta-estradiol dehydrogenase type IV and D-specific 3-hydroxyacyl CoA dehydrogenase, the central part shows D-specific hydratase activity with straight and 2-methyl-branched 2-enoyl-CoAs. The C-terminal part is similar to sterol carrier protein 2. The 80 kDa polypeptide chain ends with the tripeptide AKI, which resembles the motif SKL, the first identified peroxisome targeting signal PTS1. So far AKI, although being similar to the consensus sequence PTS1, has neither been reported to be present in mammalian peroxisomal proteins, nor has it been shown to be functional. We investigated whether the HSD17B4 gene product is targeted to peroxisomes by this C-terminal motif. Recombinant human PTS1 binding protein Pex5p interacted with the bacterially expressed C-terminal domain of the HSD17B4 gene product. Binding was competitively blocked by a SKL-containing peptide. Recombinant deletion mutants of the C-terminal domain lacking 3, 6, and 14 amino acids and presenting KDY, MIL, and IML, respectively, at their C-termini did not interact with Pex5p. The wild-type protein and mutants were also transiently expressed in the HEK 293 cells. Immunofluorescence analysis with polyclonal antibodies against the C-terminal domain showed a typical punctate peroxisomal staining pattern upon wild-type transfection, whereas all mutant proteins localized in the cytoplasm. Therefore, AKI is a functional PTS1 signal in mammals and the peroxisome targeting of the HSD17B4 gene product is mediated by Pex5p.

Simulation of vessel morphogenesis using cellular automata

We present a cellular automaton model, including lateral inhibition of an autocatalytic morphogen, as well as a genetic switch that differentiates tissue into substrate-depleting vessels. This model yields isotropic morphogenesis, including: dichotomous and lateral branching, blind vessel ends, and closed loops due to anastosmosis. The algorithm consists of a list of simple rules describing the essential biophysical features, permitting comfortable programming and fast computations. Depending on the choice of the substrate s, the model is applicable to leaf veins (s is auxin), insect trachea (s is CO2) or neovascularization (s is an angiogenesis factor). Sequential addition of rules can be correlated to evolutionary steps in leaf morphogenesis.

Two isoforms of protein disulfide isomerase alter the dimerization status of E2A proteins by a redox mechanism

We have shown previously that E2A helix-loop-helix proteins spontaneously form an intermolecular disulfide cross-link that is required for stable homodimer binding to DNA (Benezra, R. (1994) Cell 79, 1057-1067). These homodimers are important for the development of B lymphocytes but are not present in other cell lineages. We have purified two proteins that are capable of regulating the formation of this disulfide bond and found them to be members of the protein disulfide isomerase (PDI) family. By regulating the formation of the disulfide cross-link, these proteins are capable of regulating the dimerization state of E proteins. PDI-mediated reduction appears to dissociate E protein homodimers and favors heterodimer formation with other basic helix-loop-helix proteins in both a purified protein system and in cellular extracts. These studies suggest that PDI may play an important role in the regulation of E2A transcription factor dimerization and the development of the B lymphocyte lineage.

Expression of different 17beta-hydroxysteroid dehydrogenase types and their activities in human prostate cancer cells

The 17beta-hydroxysteroid dehydrogenase (17betaHSD) enzyme system governs important redox reactions at the C17 position of steroid hormones. Different 17betaHSD types (no. 1-4) have been identified to date in peripheral human tissues, such as placenta, testis, and breast. However, there is little information on their expression and activity in either normal or malignant prostate. In the present work, we have inspected pathways of 17beta-oxidation of either androgen or estrogen in human prostate cancer cells (LNCaP, DU145, and PC3) in relation to the expression of messenger RNAs (mRNAs) for 17betaHSD types 1-4. These cell systems feature distinct steroid receptor status and response to hormones. We report here that high expression levels of 17betaHSD4 were consistently observed in all three cell lines, whereas even greater amounts of 17betaHSD2 mRNA were detected solely in PC3 cells. Neither 17betaHSD1 nor 17betaHSD3 mRNAs could be detected in any cell line. From a metabolic standpoint, intact cell analysis showed a much lower extent of 17beta-oxidation of both androgen [testosterone (T)] and estrogen [estradiol (E2)] in LNCaP and DU145 cells compared to PC3 cells, where a greater precursor degradation and higher formation rates of oxidized derivatives (respectively, androstenedione and estrone) were observed. Using subcellular fractionation, we have been able to differentiate among 17betaHSD types 1-4 on the basis of their distinct substrate specificities and subcellular localization. This latter approach gave rise to equivalent results. PC3 cells, in fact, displayed a high level of microsomal activity with a low E2/T activity ratio and approximately equal apparent Km values for E2 and T, suggesting the presence of 17betaHSD2. Dehydrogenase specific activity with both E2 and T was also detected, although at lower levels, in LNCaP and DU145 cells. No evidence for reductase activity could be obtained in either the soluble or microsomal fraction of any cell line. As comparable expression levels of 17betaHSD4 were seen in the three cell lines, 17betaHSD2 is a likely candidate to account for the predominant oxidative activity in PC3 cells, whereas 17betaHSD4 may account for the lower extent of E2 oxidation seen in both LNCaP and DU145 cells. This is the first report on the expression of four different 17betaHSD types in human prostate cancer cells. It ought to be emphasized that for the first time, analysis of different 17betaHSD activities in either intact or fractionated cells harmonizes with the expression of relevant mRNAs species.

Porcine 80-kDa protein reveals intrinsic 17 beta-hydroxysteroid dehydrogenase, fatty acyl-CoA-hydratase/dehydrogenase, and sterol transfer activities

Four types of 17beta-hydroxysteroid dehydrogenases have been identified so far. The porcine peroxisomal 17beta-hydroxysteroid dehydrogenase type IV catalyzes the oxidation of estradiol with high preference over the reduction of estrone. A 2.9-kilobase mRNA codes for an 80-kDa (737 amino acids) protein featuring domains which are not present in the other 17beta-hydroxysteroid dehydrogenases. The 80-kDa protein is N terminally cleaved to a 32-kDa fragment with 17beta-hydroxysteroid dehydrogenase activity. Here we show for the first time that both the 80-kDa and the N-terminal 32 kDa (amino acids 1-323) peptides are able to perform the dehydrogenase reaction not only with steroids at the C17 position but also with 3-hydroxyacyl-CoA. The central part of the 80-kDa protein (amino acids 324-596) catalyzes the 2-enoyl-acyl-CoA hydratase reaction with high efficiency. The C-terminal part of the 80-kDa protein (amino acids 597-737) is similar to sterol carrier protein 2 and facilitates the transfer of 7-dehydrocholesterol and phosphatidylcholine between membranes in vitro. The unique multidomain structure of the 80-kDa protein allows for the catalysis of several reactions so far thought to be performed by complexes of different enzymes.

The subcellular localization of 17 beta-hydroxysteroid dehydrogenase type 4 and its interaction with actin

The porcine 17 beta-hydroxysteroid dehydrogenase type 4 is the key enzyme for the inactivation of estradiol. Its localization in peroxisomes was proven by immunogold electron microscopy. Interactions of the 17 beta-hydroxysteroid dehydrogenase with cytoskeletal proteins might be mandatory for a topical assignment of enzymatic activity to defined subcellular compartments.

The organelles containing porcine 17 beta-estradiol dehydrogenase are peroxisomes

Porcine 17 beta-estradiol dehydrogenase was recently purified and cloned. It catalyzes the NAD(+)-dependent oxidation of estradiol to estrone 360-fold more efficiently than the reverse reaction with NADPH. Immunogold electron microscopy localizes 17 beta-estradiol dehydrogenase in organelles of 120 to 500 nm with moderate electron-dense matrices bounded by single membranes. Antibodies against the peroxisomal markers catalase and acyl-CoA oxidase recognize the same organelles in double-labeling studies. This is the first report on the participation of peroxisomes in the metabolism of estradiol.

[Risk factors in hyperlipidemic patients with coronary heart disease one year after PTCA]

The reduction of modifiable risk factors in hyperlipidemic patients with coronary heart disease (CHD) receiving standard medical care in Germany has not been evaluated before. We identified all patients < 65 yrs of age with marked hyperlipidemia (Cholesterol (Chol) > 250 mg/dl, HDL < 20% Chol) among all patients who underwent PTCA during defined periods 1991/92 in the Cardiology department of the Heinrich-Heine-University. The study patients (n = 93, age 54 +/- 8 yrs, 75 men, 18 women) were evaluated 13 +/- 2 months after PTCA for modification of their risk factors, treatments, knowledge, medications and dietary habits with a structured questionnaire and a 5-day dietary protocol. At follow-up Chol and LDL were significantly reduced from 299 +/- 47 to 253 +/- 43, and from 228 +/- 47 to 189 +/- 42 mg/dl, respectively (p < 0.001). 10% of patients had an LDL < 135 mg/dl. In contrast, HDL (43 +/- 9 mg/dl) and triglycerides (242 +/- 138 mg/dl), the percentage of smokers (40%), of overweight patients (38%) and of patients with elevated blood pressure (43%) remained unchanged. During the observation period the number of contacts with physicians was high (12 (1-40)). 32% of patients participated in dietary counselling by a dietician and 42% in an in-patient rehabilitation programme. In 2/3 of patients the knowledge related to hyperlipidemia and a lipid-lowering diet was good. However, according to the dietary protocols the fat intake was high (37 +/- 7% of total calories). Lipid lowering drugs had been prescribed in 68% of patients, predominantly as monotherapy and in low dosage.(ABSTRACT TRUNCATED AT 250 WORDS)

Bumetanide and furosemide inhibited vascular endothelial cell proliferation

In this study, we examined the role of the bumetanide-sensitive Na+/K+/Cl-cotransport in the mitogenic signal of vascular endothelial cell proliferation. The activity of the Na+/K+/Cl- cotransport is dramatically decreased in quiescent subconfluent cells, as compared to subconfluent cells growing in the presence of FGF. The Na+/K+/Cl- cotransport activity of quiescent subconfluent cultures deprived of FGF decreased to 6%, whereas that of quiescent cells grown to confluency was reduced to only 33% of the activity of subconfluent cells growing in the presence of FGF. The basal low activity of Na+/K+/Cl- cotransport in the quiescent subconfluent vascular endothelial cells was dramatically stimulated by FGF. In order to explore the role of the Na+/K+/Cl- cotransport in the mitogenic signal of the endothelial cells, the effect of two specific inhibitors of the cotransport -furosemide and -bumetanide was tested on cell proliferation induced by FGF. Bumetanide and furosemide inhibited synchronized cell proliferation measured by direct counting of cells and by DNA synthesis. Inhibition by furosemide and bumetanide was reversible; removal of these compounds completely released the cells to proliferate. These results indicate that the effect of these drugs is specific and is not due to an indirect toxic effect. This study clearly demonstrates that the FGF-induced activation of the Na+/K+/Cl- cotransport plays a role in the mitogenic signal pathway of vascular endothelial cells.

Kinetics of inhibition of purified and mitochondrial cytochrome c oxidase by psychosine (beta-galactosylsphingosine)

1. Psychosine (beta-galactosylsphingosine) is the toxic agent in Krabbe's disease (globoid cells leukodystrophy). It inhibits purified bovine heart mitochondrial cytochrome c oxidase; there is a rapid phase of inhibition (complete within 10-15 s) and a slower phase (complete within 10-15 min). Both phases are also seen in rat liver mitochondria. IC50 is about 200 microM psychosine in the purified enzyme and less than 20 microM in mitochondria. Psychosine inhibition is due to binding to cytochrome oxidase, not cytochrome c. 2. Bovine heart submitochondrial particles show inhibition similar to rat liver mitochondria. However, although proteoliposomes containing bovine heart cytochrome oxidase show an identical fast phase, they have no noticeable slow phase of inhibition. Addition of phospholipid liposomes to submitochondrial particles relieved the majority of psychosine inhibition, consistent with the removal of those molecules binding in the slow phase. Psychosine can inhibit cytochrome oxidase molecules facing in either direction in proteoliposomes and submitochondrial particles, suggesting that it can rapidly interact with both sides of a membrane when added externally. 3. At high ionic strength, the presence of psychosine decreases the Vmax. of cytochrome oxidase with little effect on the Km for cytochrome c. This non-competitive inhibition suggests that the psychosine-enzyme complex is kinetically inactive and not labile over the time course of the assay. Psychosine does not inhibit the reduction of haem a or haem a3 by artificial electron donors, but does inhibit the reduction of haem a by cytochrome c.

Phototaxis of Spiral Waves

The drift of spiral waves toward regions of higher light intensity was observed experimentally in the ruthenium-catalyzed Belousov-Zhabotinsky reaction. A light gradient can thus be used to manipulate optical information in new computational systems based on photochemical media. The drift of a gradient that is rotationally invariant in space is three to four times as fast as that of a translationally invariant gradient. Simulations based on the use of a cellular automaton, which is made isotropic by a semirandom distribution of cells, are in agreement with the experimental results.

Na+/K+/Cl- cotransport is stimulated by a Ca(++)-calmodulin-mediated pathway in BALB/c 3T3 fibroblasts

In the present study, we investigated the role of intracellular Ca++ in the stimulation of the Na+/K+/Cl- cotransport in synchronized BALB/c 3T3 cells. The Na+/K+/Cl- cotransport was stimulated by the growth factors EGF, TGF-alpha, IGF-1, and IGF-2, which do not activate protein kinase C, but do induce a transient increase in free cytoplasmic Ca++. In addition, direct activation of protein kinase C by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) did not affect the Na+/K+/Cl- cotransport activity of quiescent cells. The Na+/K+/Cl- cotransport was also stimulated by the above mitogens in cells pretreated with the phorbol ester TPA. This treatment led to a progressive decline in the activity of cellular protein kinase C. This result implies that cells deficient in protein kinase C may still support stimulation of the Na+/K+/Cl- cotransport. Taken as a whole, these findings suggest that the Na+/K+/Cl- cotransport is stimulated predominantly by a protein kinase C-independent mechanism in BALB/c 3T3 fibroblasts. Both the intracellular Ca++ antagonist 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) and two potent calmodulin antagonists, trifluoperazine (TFP) and chloropromazine (CP), blocked serum- and mitogen-stimulated Na+/K+/Cl- cotransport. These results suggest that the Na+/K+/Cl- cotransport is stimulated by an increase of intracellular Ca++ and subsequently by a Ca(++)-calmodulin-mediated pathway in the synchronized BALB/c 3T3 fibroblasts.

Phorbol ester TPA inhibits the stimulation of bumetanide-sensitive Na+/K+/Cl- transporter by different mitogens in quiescent BALB/c 3T3 mouse fibroblasts

In this study we examined the effect of the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on the bumetanide-sensitive Na+/K+/Cl- transporter in quiescent BALB/c 3T3 cells. We have shown that exposure of quiescent BALB/c 3T3 cultures to phorbol ester did not inhibit the basal bumetanide-sensitive Rb+ influx or efflux. In fact, at high concentration (100 ng/ml), TPA slightly stimulated the bumetanide-sensitive Rb+ influx and efflux. However, when the quiescent cultures were stimulated by serum or by defined growth factors, the stimulated fraction of the bumetanide-sensitive Rb+ influx was drastically inhibited by exposure of the cells to the phorbol ester TPA. Based on the above findings, we propose that activation of protein kinase C by the phorbol ester TPA does not inhibit the Na+/K+/Cl- cotransport activity; however it does suppress only the growth-factors-stimulated fraction of the cotransport in quiescent BALB/c 3T3 cells. These data propose that activation of kinase C has a regulatory feedback effect on the stimulation of the Na+/K+/Cl- cotransport activity by growth factors.

Input-response relationships in the dynamics of glycolysis

The dynamic response of glycolysis is investigated using a two-enzyme model with three different type of input flux time dependences: constant, sinusoidal, and amplitude or frequency modulated (AM or FM) input flux. The analysis reveals that the system acts as a device which transduces amplitudes and frequencies of the input function into complex and remarkably diverse response patterns. This device may have more than one response possibilities for a single input function, owing to the coexistence of attractors in phase space. In such a case one response function can be switched over into the other by short substrate pulses. Stroboscopic plots reveal that chaotic regimes obtained under sinusoidal input flux obey a stretch-fold-press process, similar to the baker's transformation, upon a change of the stroboscoping phase. Chaotic oscillations obtained under AM or FM conditions often show a much higher degree of randomness than those obtained under sinusoidal input. This is expressed quantitatively by an enhanced Liapunov dimension of the attractors.