Impact of acute psychosocial stress on attentional control in humans. A study of evoked potentials and pupillary response

Psychosocial stress has increased considerably in our modern lifestyle, affecting global mental health. Deficits in attentional control are cardinal features of stress disorders and pathological anxiety. Studies suggest that changes in the locus coeruleus-norepinephrine system could underlie the effects of stress on top-down attentional control. However, the impact of psychosocial stress on attentional processes and its underlying neural mechanisms are poorly understood. This study aims to investigate the effect of psychosocial stress on attentional processing and brain signatures. Evoked potentials and pupillary activity related to the oddball auditory paradigm were recorded before and after applying the Montreal Imaging Stress Task (MIST). Electrocardiogram (ECG), salivary cortisol, and subjective anxiety/stress levels were measured at different experimental periods. The control group experienced the same physical and cognitive effort but without the psychosocial stress component. The results showed that stressed subjects exhibited decreased P3a and P3b amplitude, pupil phasic response, and correct responses. On the other hand, they displayed an increase in Mismatch Negativity (MMN). N1 amplitude after MIST only decreased in the control group. We found that differences in P3b amplitude between the first and second oddball were significantly correlated with pupillary dilation and salivary cortisol levels. Our results suggest that under social-evaluative threat, basal activity of the coeruleus-norepinephrine system increases, enhancing alertness and decreasing voluntary attentional resources for the cognitive task. These findings contribute to understanding the neurobiological basis of attentional changes in pathologies associated with chronic psychosocial stress.

¿Modula el efecto del feedback la percepción de competencia del entrenador?

El objetivo fue analizar el efecto de diferentes tipos de feedback sobre variables psicológicas y de rendimiento en función de la percepción del deportista de la competencia del entrenador. Se realizó un estudio de caso con 33 futbolistas asignados aleatoriamente a tres condiciones experimentales (feedback positivo, negativo y ausencia de feedback). Se midieron velocidad y precisión de lanzamientos a portería, valoración de competencia, competencia percibida, motivación autónoma y vitalidad subjetiva. Se empleó un nivel ? de 0,05 para los análisis. El grupo feedback positivo exhibió niveles más altos de valoración de competencia, competencia percibida, motivación autónoma y bienestar, que los de feedback negativo y ausencia de feedback, en sujetos con alta percepción de competencia del entrenador. Este efecto no se observó en aquellos con baja percepción de competencia del entrenador. La percepción del jugador sobre la competencia del entrenador podría ser un factor en la modulación de las diferencias generadas en cuanto al tipo de feedback.

A Left sided site of origin is associated with adverse cardiovascular outcomes in patients with LV dysfunction undergoing PVC ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Epidemiological studies suggested that premature ventricular complexes (PVCs) are associated with cardiac mortality. But data are still inconclusive.

Aim

This study sought to analyze predictors of adverse outcomes in a population of patients with left ventricular (LV) systolic dysfunction who underwent PVC ablation.

Methods

135 consecutive patients [100 (74%) men, 59 +12 y.o.] with LV systolic dysfunction [LV ejection fraction (LVEF) <50%] and frequent PVCs who underwent PVC ablation were included in a multicenter prospective international register. Patients were followed-up at 6 and 12 months and annually thereafter. The last evaluation performed was considered the long-term follow-up (LTFUP) evaluation. Cardiac mortality and/or cardiac transplantation and/or admission for heart failure was considered the primary endpoint.

Results

82 (61%) patients had a left-sided PVC’s site of origin (LS-SOO), 51 (38%) had a right-sided SOO (RS-SOO) whereas SOO could not be determined in 2 (1%) patients. LS-SOO patients were older (61 ± 11 vs 52 ± 10, p < 0.001) more frequently men [71 (87%) vs 27 (53%), p < 0.001] with previous history of atrial fibrillation (AF) [14 (15%) vs 0, p = 0.001] and with a previously diagnosed structural heart disease (SHD) [43 (52%) vs 6 (11%), p < 0.001].

After a mean follow-up of 39 ± 21 months (range 24-94 months) there was a significant reduction in the PVC burden from 24 ± 13% at baseline to 4 ± 6% at LTFUP, p < 0.001; LVEF improved from 33 ± 8% at baseline to 41 ± 13% at LTFUP (p < 0.001) and NYHA class from 2.1 ± 0.6% to 1.4 ± 0.6% (p < 0.001); BNP levels decreased from 237 ± 231 pg/mL to 137 ± 185 pg/mL (p = 0.001). The primary end-point was reached in 10% patients (7 cardiac deaths, 1 cardiac transplantation and 5 heart failure admisions), 14,8% in LS-SOO and 1,9% in RS-SOO patients, log rank = 0.05 (Figure 1).

Conclusions

Among patients with LV dysfunction who underwent PVC ablation, those with LS-SOO were older and more frequently had AF and SHD. LS-SOO was associated with adverse cardiovascular outcomes. These findings suggest that PVCs with LS and RS-SOO should be considered as two different clinicals entities, with different prognostic values. Abstract Figure 1

Temperature and photoperiod effects on dormancy status and life cycle parameters in Aedes albopictus and Aedes aegypti from subtropical Argentina

Aedes albopictus (Diptera: Culicidae) distribution is bounded to a subtropical area in Argentina, while Aedes aegypti (Diptera: Culicidae) covers both temperate and subtropical regions. We assessed thermal and photoperiod conditions on dormancy status, development time and mortality for these species from subtropical Argentina. Short days (8 light : 16 dark) significantly increased larval development time for both species, an effect previously linked to diapause incidence. Aedes albopictus showed higher mortality than Ae. aegypti at 16 °C under long day treatments (16 light : 8 dark), which could indicate a lower tolerance to a sudden temperature decrease during the summer season. Aedes albopictus showed a slightly higher percentage of dormant eggs from females exposed to a short day, relative to previous research in Brazilian populations. Since we employed more hours of darkness, this could suggest a relationship between day-length and dormancy intensity. Interestingly, local Ae. aegypti presented dormancy similar to Ae. albopictus, in accordance with temperate populations. The minimum dormancy in Ae. albopictus would not be sufficient to extend its bounded distribution. We believe that these findings represent a novel contribution to current knowledge about the ecophysiology of Ae. albopictus and Ae. aegypti, two species with great epidemiological relevance in this subtropical region.

659Left atrial wall thickness evaluation during atrial fibrillation redo procedures

Funding Acknowledgements

Dr Teres was funded by Swiss Heartrhythm Foundation

Introduction

pulmonary vein (PV) reconnections due to gaps on circumferential ablation lines are responsible for atrial fibrillation recurrences after catheter ablation. We sought to analyze the local left atrial wall thickness (LAWT) of PV line gaps at AF redo ablation during real-time catheter positioning. LAWT was measured on the MDCT 3D reconstruction and fused with the LA anatomy using CARTO-merge.

Objective

To analyze the relationship between local reconnection gaps and the LAWT during AF redo procedures.

Methods

Single-Center cohort study that included 41 consecutive patients referred for AF redo procedure. All patients had a MDCT prior to the ablation procedure. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium. Each PV line was subdivided into 8 segments and mean LAWT was computed. During the procedure, the local gap was defined as the earliest activation site at the reconnected segment of the circumferential PV line (Figure 1A & 1B).

Results

41 patients [31 (75.6%) male, age 60 ± 10 years] were included. Mean LAWT was 1.36 ± 0.20 mm. Mean PV circumferential line WT was higher in left PVs than in the right PVs 1.68 ± 0.57 vs. 1.31 ± 0.39 mm p < 0.001 respectively. Mean WT of the reconnected points was 44% higher than the mean WT of the segment where the reconnection was located. Mean reconnection point WT was at the 87th percentile of the circumferential line in the LPVs and at the 76th percentile in the RPVs. The reconnected point WT was higher in the LPVs than RPVs 2.13 ± 1.14 vs. 1.47 ± 0.48 mm p < 0.001 respectively.  The most frequent location for reconnections was the left anterior carina (71%), with a mean WT of 2.24 ± 0.91mm; and the right anterior carina (56%) with a mean WT of 1.57 ± 0.62mm (Figure 2A & 2B).

Conclusions

Reconnection points were more frequently present in the thicker segments of the PV circumferential line. The most frequently reconnected segment was the anterior carina in both right and left PVs. Atrial wall thickness maps derived from MDCT are useful to guide AF redo procedures.

Abstract Figure. 1) Activation & WT map; 2) Segment WT

P1010Association between left atrial fibrosis detected by cardiac magnetic resonance and endocardial electroanatomic mapping in the evaluation of the electrophysiological substrate in atrial fibrillation

Background

Atrial fibrillation (AF) is related to left atrial fibrosis, but its identification by late magnetic resonance imaging (LGE) with gadolinium (LGE) persists in controversy due to heterogeneous results in its correlation with the electroatomic map (EAM) and the difficulty of perform histological studies in humans.

Purpose

We try to examine the point-by-point association between high density EAM and LGE-MRI using an automatic and reproducible method.

Methods

A LGE-MRI was performed in 16 patients prior to ablation. Three different areas were established depending on the intensity of normalized enhancement for each patient according to their blood group with the image intensity ratio (IIR) (healthy <1.20, border area (BZ) ≥1.20 <1.32 and scar ≥1.32). The high density electroanatomic maps of the left atrium (LA) were projected onto the MRI, obtaining an automatic correlation point by point.

Results

The study obtained significant differences (p < 0.001) between voltage (mV) and CV (mm/ms) among healthy, BZ and scar areas, as well a significant inverse correlation (p < 0.001) between voltage and IIR (R=-0.39). It obtained too a significant correlation between CV and IIR (R=-0.24), but this showed a greater correlation in those patients who have the least dilated LA (p = 0.02).

Conclusions

LGE-MRI and EAM showed good correlation in delineating potential pathologic substrate in AF, but left atrium dilation could reduce the performance of the CMR in this task. Conduction velocity could be more sensitive than voltage and LGE-MRI to detect incipient substrate in AF.

Voltage and conduction velocity values Area /IIR Velocity (mm/ms) Voltage (mV) I / <.20 1.036(0.913-1.158) 1.593(1.489-1.696) 2 / ≥1.20 and <1.32 0.722(0.590-0.850) 0.792 (0.649-0,935) 3 / ≥1.32 0.623(0.473-0,733) 0.444(0.245-0.642) Voltage and conduction velocity values in the three areas of the LGE-RMN.

Abstract Figure. Correlation among voltage, VC and LA

Plankton crustaceans in bays with different trophic status in Llanquihue lake (41° S Chile)

The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is to analyze the trophic status and zooplankton relative abundance in different bays of Llanquihue lake. It was found direct associations between chlorophyll a with daphnids percentage, total dissolved nitrogen with reactive soluble phosphorus nitrogen/phosphorus molar radio with cyclopoids percentage, and an inverse relation between daphnids and calanoids percentages. The occurrence of three kinds of microcrustacean assemblages and environmental conditions was evidenced: the first one with high calanoids percentage, low species number and low chlorophyll and nutrients concentration, a second with moderate chlorophyll and nutrients concentration and moderate daphnids percentage; high species number and a third site with high chlorophyll and nutrients concentration, high daphnids percentage and high species number. Daphnids increase under mesotrophic status, agree with similar results observed for southern Argentinean and New Zealand lakes.

N-acetylcysteine inhibits lipid accumulation in mouse embryonic adipocytes

Oxidative stress plays critical roles in the pathogenesis of diabetes, hypertension, and atherosclerosis; some authors reported that fat accumulation correlates to systemic oxidative stress in human and mice, but cellular redox environment effect on lipid accumulation is still unclear. In our laboratory we used mouse embryonic fibroblasts (undifferentiated cells: CC), which are capable of differentiating into mature adipocytes (differentiated cells: DC) and accumulate lipids, as obesity model. Here we analyzed the role of the well-known antioxidant and glutathione precursor N-acetylcysteine (NAC) in cellular MAPK modulation and lipid accumulation. We evaluated the effect of NAC on the adipogenic differentiation pathway using different doses: 0.01, 0.1, 1 and 5 mM; no toxic doses in these cells. A dose of 5 mM NAC [DCN-5] provoked a significant decrease in triglyceride accumulation (72±10 [DCN-5] vs 169±15 [DC], p<0.01), as well in Oil Red O stained neutral lipid content (120±2 [DCN-5] vs 139±12 [DC], p<0.01). Molecular mechanisms responsible for adipogenic differentiation involve increase of the expression of phosphoERK½ and phosphoJNK, 5 mM NAC treatment inhibited both pERK½ and pJNK protein levels. We also evaluated the mitotic clonal expansion (MCE) which takes place during adipogenesis and observed an increase in DC at a rate of 1.5 cells number compared to CC at day 2, whereas the highest doses of NAC significantly inhibited MCE. Our results suggest that NAC inhibits lipid accumulation and the MAPK phosphorylation in mouse embryonic fibroblasts during adipogenic differentiation and further contribute to probe the importance of cellular redox environment in adipogenesis.

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NAC, up to 5 mM, is not toxic in adipocytes obtained from mouse embryonic fibroblasts.

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NAC inhibited phosphorylation of ERK½ and JNK in adipogenic differentiation.

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NAC inhibited mitotic clonal expansion in adipogenic differentiation.

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NAC inhibited triglyceride and lipid accumulation in mouse embryonic adipocytes.

How imagery changes self-motion perception

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Imagined self-motion differentially modulates vestibular processing.

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Differential modulation affects both high- and low-order vestibular processing.

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Congruent and incongruent imagery have opposing effects.

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Modulation reported is specific to mental imagery and not an attentional bias.

Imagery and perception are thought to be tightly linked, however, little is known about the interaction between imagery and the vestibular sense, in particular, self-motion perception. In this study, the observers were seated in the dark on a motorized chair that could rotate either to the right or to the left. Prior to the physical rotation, observers were asked to imagine themselves rotating leftward or rightward. We found that if the direction of imagined rotation was different to the physical rotation of the chair (incongruent trials), the velocity of the chair needed to be higher for observers to experience themselves rotating relative to when the imagined and the physical rotation matched (on congruent trials). Accordingly, the vividness of imagined rotations was reduced on incongruent relative to congruent trials. Notably, we found that similar effects of imagery were found at the earliest stages of vestibular processing, namely, the onset of the vestibular–ocular reflex was modulated by the congruency between physical and imagined rotations. Together, the results demonstrate that mental imagery influences self-motion perception by exerting top-down influences over the earliest vestibular response and subsequent perceptual decision-making.

GAL3ST2 from mammary gland epithelial cells affects differentiation of 3T3-L1 preadipocytes

INTRODUCTION

In the mammary gland, the involution that occurs when lactation ends is an important period for cancer development. We have previously demonstrated stromal-epithelium interactions evaluating conditioned medium of adipose tissue on breast epithelial metalloproteases activity (Creydt et al., Clin Transl Oncol 15:124-131, 2013). Here, we evaluated the effects of conditioned medium of breast epithelial mammary cells on stromal cells.

MATERIALS AND METHODS

Conditioned medium from normal murine mammary gland cell line (NMuMG) and conditioned medium proteins were obtained. Then, they were evaluated on modulation of adipocyte differentiation, using 3T3-L1 cell line.

RESULTS

We described, for the first time, that breast epithelial mammary cells could produce the enzyme galactose 3-O-sulfotransferase 2 (GAL3ST2). Importantly, GAL3ST2 is present in NMMuMG and two human breast cancer cell lines, and it is more strongly expressed in more metastatic tumors. When 3T3-L1 preadipocyte differentiation was triggered in the presence of conditioned medium from NMuMG or GAL3ST2, triglyceride accumulation was decreased by 40 % and C/EBPβ expression by 80 % in adipocytes. In addition, the expression of FABP4 (aP2), another marker of adipocyte differentiation, was inhibited by 40 % in GAL3ST2-treated cells.

CONCLUSIONS

Taken together, these results suggest that GAL3ST2 would interfere with normal differentiation of 3T3-L1 preadipocytes; raising the possibility that it may affect normal differentiation of stromal preadipocytes and be a link to tumor metastatic capacity.

High-speed free-space quantum key distribution system for urban daylight applications

We report a free-space quantum key distribution system designed for high-speed key transmission in urban areas. Clocking the system at gigahertz frequencies and efficiently filtering background enables higher secure key rates than those previously achieved by similar systems. The transmitter and receiver are located in two separate buildings 300 m apart in downtown Madrid and they exchange secure keys at rates up to 1 Mbps. The system operates in full bright daylight conditions with an average secure key rate of 0.5 Mbps and 24 h stability without human intervention.

[Results of long-term follow-up after local excision for well-selected low rectal cancers]

OBJECTIVE

to evaluate our results about local failure, total recurrence and survival.

METHOD

twenty-one patients underwent a complete local transanal excision for low rectal cancer in our institution during an 18-year period (1985-2003). Preoperative staging included clinical, endoscopic, CT, EUSR, and histopathological findings; pathological specimens were 4 T1, 13 T2 and 4 T3 tumors. None of the T1 patients received another treatment; 6 out of 13 T2 and all of T3 cases were treated with chemoradiotherapy. None of the latter underwent radical surgery.

RESULTS

follow-up (median 74 months) proved 23.8% for total recurrence and 19.0% for local failure (out of all 3 T2 cases only one received chemoradiotherapy, and one T3 received adjuvant treatment). Five-year survival is 95.2%.

CONCLUSIONS

this experience allows us to assert that local excision is a good choice in well-selected low rectal cancer patients; for T2 tumors chemoradiotherapy is necessary; in T3 patients radical surgery must be prompt.

Genetic deficiency of human mast cell alpha-tryptase

BACKGROUND

Human alpha- and beta-tryptases are proteases secreted by mast cells. Beta (but not alpha) tryptases are implicated in asthma. Genes encoding both types of tryptases cluster on chromosome 16p13.3.

OBJECTIVE

This study examines the hypothesis, generated from mapping data, that alpha-alleles compete with some beta-alleles at one locus and that an adjacent locus contains beta-alleles exclusively. This hypothesis predicts that beta-alleles outnumber alpha and that some genomes lack alpha genes altogether.

METHODS

To test this hypothesis, we developed PCR-based techniques to distinguish alpha from beta genes. We then genotyped genomic DNA from individuals and tryptase-expressing cell lines.

RESULTS

In support of our hypothesis, we find that alpha-tryptase deficiency affects 80/274 (29%) of individuals surveyed. The genotype of the alpha-deficient individuals is betabetabetabeta, due to inheritance of four beta genes. The percentage of the population with the mixed genotypes alphaalphabetabeta and alphabetabetabeta is 21% and 50%, respectively. Accounting for all alpha- and beta-alleles at the tandem loci on 16p13.3, overall alpha-allele frequency is only 0.23, with beta-alleles considerably outnumbering alpha as hypothesized. In samples of defined ethnicity, alpha deficiency affects 45% of Caucasians, but a much lower percentage of other backgrounds, including African-Americans and Asians. Examination of cell lines reveals that HMC-1 and U-937 lack alpha-genes; thus, lack of alpha transcripts in these cells is due to absence of alpha-genes rather than beta-selective transcription. By contrast, alpha-transcribing Mono Mac 6 and KU812 cells contain alpha- and beta-genes.

CONCLUSIONS

Genetic alpha-tryptase deficiency is common and varies strikingly between ethnic groups. Because beta-tryptases are implicated in allergic disorders, inherited differences in alpha/beta-genotype may affect disease susceptibility, severity and response to tryptase inhibitor therapy.

[Non familial juvenile multiple polyposis. A case report]

We report a 15 years old girl presenting with severe hematochezia with secondary anemia and hemodynamic decompensation, rectal prolapse and spontaneous anal elimination of polyps. She had no family history of polyposis and a search for the disease in her close relatives was negative. A complete diagnostic work up did not find polyps in other segments of the digestive tract. Colonoscopy showed more than 200 polyps between the cecum and the rectum. Pathological analysis confirmed the presence of retention polyps with adenomatous areas and mild atypia. The patient was subjected to a proctocolectomy with ileal pouch and sphincteric preservation, using a mechanical suture. Postoperative evolution was uneventful and after 24 months of follow up, the patient is asymptomatic, with two stool movements per day and without incontinence.

Kainate-induced seizures alter protein composition and N-methyl-D-aspartate receptor function of rat forebrain postsynaptic densities

The postsynaptic density is a highly dynamic structure, which is reorganized in an activity-dependent manner. An animal model for temporal lobe epilepsy, i.e. kainate-induced limbic seizures in rats, was used to study changes in postsynaptic density composition after extensive synaptic activity. Six hours after kainate injection, the protein content of the postsynaptic density fractions from rats that developed strong seizures was increased three-fold compared to saline-treated controls. Immunoblot analysis revealed that the relative amounts of metabotropic glutamate receptor 1alpha, N-ethylmaleimide-sensitive fusion protein, protein kinases C, Fyn and TrkB, as well as the neuronal nitric oxide synthase, were significantly higher in seizure-developing than in control rats. In contrast, the relative contents of the kainate receptor KA2 subunit, beta-actin, alpha-adducin and the membrane-associated guanylate kinase homolog SAP90/PSD-95 were decreased. The relative amounts of additional postsynaptic density proteins, including alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate and N-methyl-D-aspartate receptor subunits, calcium/calmodulin-dependent kinase type II, casein kinase 2, tubulin, microtubule-associated protein 2B, the membrane-associated guanylate kinase homolog SAP102, and proline-rich synapse-associated protein 1/cortactin binding protein 1/Shank2 remained essentially unchanged. To assess possible changes in postsynaptic performance, postsynaptic densities were isolated from control and epileptic rats, incorporated into giant liposomes and N-methyl-D-aspartate receptor currents were recorded. A significant reduction in the mean conductance was observed in patches containing postsynaptic densities from animals with high seizure activity. This was due to the presence of reduced conductance levels in each membrane patch compared to control postsynaptic density preparations. From these data, we suggest that intense synaptic activity associated with seizures modifies the composition of postsynaptic densities and has profound consequences on the function of the N-methyl-D-aspartate receptors present in them. This rearrangement may accompany impairment of synaptic plasticity.

Direct evidence for the contribution of activated N-ras and K-ras oncogenes to increased intrinsic radiation resistance in human tumor cell lines

Transformation with ras oncogenes results in increased radiation sur vival in many but not all cells. In addition, prenyltransferase inhibitors which inhibit ras proteins by blocking posttranslational modification radiosensitize cells with oncogenic ras. These findings suggest that oncogenic ras contributes to intrinsic radiation resistance. However, because introduction of ras oncogenes does not increase radiation survival in all cells and because prenyltransferase inhibitors target molecules other than ras, these studies left the conclusion that ras increases the intrinsic radi ation resistance of tumor cells in doubt. Here we show that genetic inactivation of K- or N-ras oncogenes in human tumor cells (DLD-1 and HT1080, respectively) leads to increased radiosensitivity. Reintroduction of the activated N-ras gene into the HT1080 line, having lost its mutant allele, resulted in increased radiation resistance. This study lends further support to the hypothesis that expression of activated ras can contribute to intrinsic radiation resistance in human tumor cells and extends this finding to the K- and N- members of the ras family. These findings support the development of strategies that target ras for inactivation in the treatment of cancer.

[Development of products for the elderly population: vitamin enriched pudding]

An instant dessert powder, pudding type was developed to be consumed at lunch or dinner time. The dessert was designed to be prepared in skim milk and meets the nutritional needs of elderly people. The dessert contains modified starch, carragenine, vegetal fat, sacharose. Each serving has been enriched with 30% of the daily vitamin requirement advised for adults over 51 years old. The optimized process was carried out according to the Karlsruhe test. Each serving consists of 22g powder prepared in proportion of 18% in skim milk. The optimized dessert powder was controlled by means of physical, chemical and microbiological analyses. The sensory quality was determined in the ready to eat product and the acceptability level was measured in a group of people selected according to the characteristics of the target population. The dessert powder contains 1.1% protein, 5.2% fats, 89.76% carbohidrates, and provides 409 Kcal/100g. Both the sensory and microbiological quality were good and the level of acceptance reached 98%.

[Epidemiologic and nutritional characteristics of the elderly]

A sample of 1365 elders of both sexes from rural and urban populations was studied. Thirty four percent of the subjects were older that 80 years. 21.6% lived alone, 25% were illiterate and 50% did not finish elementary school. Mental impairment was found in 5.6% and body mass index was normal in 41.4% of subjects. Eighty seven percent did not smoke and 80% were teetotalers. Medical services were requested at least every one year by 15.4% and twice a year by 11.9% of subjects. These numbers will help to design preventive and interventional policies directed to this segment of the population.

Improved detection of mutations in the p53 gene in human tumors as single-stranded conformation polymorphs and double-stranded heteroduplex DNA

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Mutations in p53 as potential molecular markers for human breast cancer

Based on the high incidence of loss of heterozygosity for loci on chromosome 17p in the vicinity of the p53 locus in human breast tumors, we investigated the frequency and effects of mutations in the p53 tumor suppressor gene in mammary neoplasia. We examined the p53 gene in 20 breast cancer cell lines and 59 primary breast tumors. Northern blot analysis, immunoprecipitation, and nucleotide sequencing analysis revealed aberrant mRNA expression, over-expression of protein, and point mutations in the p53 gene in 50% of the cell lines tested. A multiplex PCR assay was developed to search for deletions in the p53 genomic locus. Multiplex PCR of genomic DNA showed that up to 36% of primary tumors contained aberrations in the p53 locus. Mutations in exons 5-9 of the p53 gene were found in 10 out of 59 (17%) of the primary tumors studies by single-stranded conformation polymorphism analysis. We conclude that, compared to amplification of HER2/NEU, MYC, or INT2 oncogene loci, p53 gene mutations and deletions are the most frequently observed genetic change in breast cancer related to a single gene. Correlated to disease status, p53 gene mutations could prove to be a valuable marker for diagnosis and/or prognosis of breast neoplasia.

Regulation of inhibin subunit messenger ribonucleic acid levels by gonadotropins, growth factors, and gonadotropin-releasing hormone in cultured rat granulosa cells

Cultured rat granulosa cells have provided a useful model to examine the hormonal regulation of inhibin secretion. In the present study we have used the cloned rat inhibin alpha- and beta A-subunit cDNAs to characterize the influences of gonadotropins, growth factors, and GnRH on inhibin subunit mRNA levels in granulosa cells obtained from immature estrogen-treated rats. Cells were cultured in medium with or without added hormones. Total RNA from cultured cells was extracted and hybridized with 32P-labeled inhibin alpha- and beta A-subunit cRNA or beta-actin cDNA probes, and inhibin subunit mRNA levels were normalized with beta-actin mRNA levels. Treatment of granulosa cells with FSH increased inhibin alpha- and beta A-subunit mRNA levels in a dose-dependent manner. Similarly, LH, but not PRL, increased alpha- and beta A-subunit mRNA levels in granulosa cells pretreated with FSH to induce functional LH and PRL receptors. The effects of FSH and LH on inhibin subunit mRNA levels were mimicked by forskolin, which increased alpha- and beta A-subunit transcripts in a dose- and time-dependent manner, suggesting involvement of the cAMP-dependent protein kinase-A pathway. Since several growth factors have been shown to influence inhibin secretion, their effects on inhibin subunit mRNA levels were also studied. Treatment of cells with transforming growth factor-beta 1 increased both basal and FSH-stimulated inhibin alpha- and beta A-subunit mRNA content, whereas insulin-like growth factor-I had no significant effect. In contrast, both epidermal growth factor (EGF) and basic fibroblast growth factor (FGF) markedly suppressed both basal and FSH-stimulated inhibin subunit transcript levels. The inhibitory effects of EGF and basic FGF were dose dependent and persisted from 12-72 h of incubation. The regulatory peptide GnRH, which decreases inhibin secretion, was also found to suppress FSH-stimulated inhibin alpha- and beta A-subunit mRNA levels in a dose-dependent manner. Furthermore, the effects of GnRH could be counteracted by coincubation with a GnRH antagonist, suggesting the involvement of specific GnRH-binding sites in GnRH action. These studies indicate that, except for insulin-like growth factor-I, the effects of gonadotropins, growth factors (EGF, basic FGF, and transforming growth factor-beta 1), and GnRH on inhibin secretion are related to their regulation of inhibin alpha- and beta A-subunit mRNA levels.

Activin stimulation of inhibin secretion and messenger RNA levels in cultured granulosa cells

Recent reports suggest that activin (the dimer of inhibin beta subunits with FSH-releasing activity) has specific receptors on ovarian granulosa cells. The present study examined the effects of purified porcine activin on inhibin secretion and mRNA levels in granulosa cells obtained from immature, estrogen-treated rats. Cells were cultured for 48 h in culture media, or media containing FSH (10 ng/ml) and/or activin (30 ng/ml). Western blot analyses performed with affinity-purified antisera to inhibin alpha- and beta A-subunits revealed that treatment with either FSH or activin increased the secretion of inhibin alpha beta dimer (Mr 30,000), with a further increase after cotreatment. These results were confirmed by an inhibin alpha-subunit RIA, which revealed 7-, 14-, and 71-fold increases in the secretion of immunoreactive inhibin-alpha by activin, FSH, and activin plus FSH, respectively. TGF beta, a structural homolog of activin, also stimulated inhibin release, whereas follistatin was ineffective. Total RNA from cultured cells was hybridized with 32P-labeled inhibin alpha-subunit cRNA or beta-actin cDNA probes, and inhibin-alpha message levels were normalized with beta-actin mRNA levels. Northern blot analysis revealed that treatment with FSH and activin increased hybridization of a 1.5 kilobase (kb) message, corresponding to the inhibin alpha-subunit mRNA. Slot blot analyses indicated a 6- and 8-fold stimulation of inhibin alpha-subunit mRNA levels by FSH and activin, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Granulosa cell aromatase bioassay: changes of bioactive FSH levels in the female

Some modified forms of follicle-stimulating hormone (FSH) may not cross react with the FSH antibody used in the radioimmunoassay (RIA), but still retain their biological activities. Therefore, estimates of immunoreactive FSH may not correspond with FSH bioactivity. The use of in vitro FSH bioassays may disclose possible roles of these heterogenous forms in vivo under various conditions. This review will focus on the history of FSH bioassays, and the widely used in vivo Steelman and Pohley bioassay, based on ovarian weight increase after injection into female rats, is discussed. Since 1971 different biological activities of FSH in various target tissues have been used for the in vitro estimates of FSH bioactivity. The aromatase bioassays involve the measurement of oestradiol in medium of FSH treated Sertoli cells or granulosa cells in culture. Estimates of FSH bioactivity, using the rat granulosa cell bioassay, in serum and urine or normally cycling women, during gonadotropin-releasing hormone-antagonist treatment in hypergonadotropic hypogonadal women and during different stages of female pubertal development will be discussed in more detail.