Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances, Weak Lensing, and Galaxy Correlations

We present the first joint analysis of cluster abundances and auto or cross-correlations of three cosmic tracer fields: galaxy density, weak gravitational lensing shear, and cluster density split by optical richness. From a joint analysis (4×2pt+N) of cluster abundances, three cluster cross-correlations, and the auto correlations of the galaxy density measured from the first year data of the Dark Energy Survey, we obtain Ω_{m}=0.305_{-0.038}^{+0.055} and σ_{8}=0.783_{-0.054}^{+0.064}. This result is consistent with constraints from the DES-Y1 galaxy clustering and weak lensing two-point correlation functions for the flat νΛCDM model. Consequently, we combine cluster abundances and all two-point correlations from across all three cosmic tracer fields (6×2pt+N) and find improved constraints on cosmological parameters as well as on the cluster observable-mass scaling relation. This analysis is an important advance in both optical cluster cosmology and multiprobe analyses of upcoming wide imaging surveys.

Constraints on Dark Matter Properties from Observations of Milky Way Satellite Galaxies

We perform a comprehensive study of Milky Way (MW) satellite galaxies to constrain the fundamental properties of dark matter (DM). This analysis fully incorporates inhomogeneities in the spatial distribution and detectability of MW satellites and marginalizes over uncertainties in the mapping between galaxies and DM halos, the properties of the MW system, and the disruption of subhalos by the MW disk. Our results are consistent with the cold, collisionless DM paradigm and yield the strongest cosmological constraints to date on particle models of warm, interacting, and fuzzy dark matter. At 95% confidence, we report limits on (i) the mass of thermal relic warm DM, m_{WDM}>6.5  keV (free-streaming length, λ_{fs}≲10h^{-1}  kpc), (ii) the velocity-independent DM-proton scattering cross section, σ_{0}<8.8×10^{-29}  cm^{2} for a 100 MeV DM particle mass [DM-proton coupling, c_{p}≲(0.3  GeV)^{-2}], and (iii) the mass of fuzzy DM, m_{ϕ}>2.9×10^{-21}  eV (de Broglie wavelength, λ_{dB}≲0.5  kpc). These constraints are complementary to other observational and laboratory constraints on DM properties.

Genome-wide profiling of non-smoking-related lung cancer cells reveals common RB1 rearrangements associated with histopathologic transformation in EGFR-mutant tumors

BACKGROUND

The etiology and the molecular basis of lung adenocarcinomas (LuADs) in nonsmokers are currently unknown. Furthermore, the scarcity of available primary cultures continues to hamper our biological understanding of non-smoking-related lung adenocarcinomas (NSK-LuADs).

PATIENTS AND METHODS

We established patient-derived cancer cell (PDC) cultures from metastatic NSK-LuADs, including two pairs of matched EGFR-mutant PDCs before and after resistance to tyrosine kinase inhibitors (TKIs), and then performed whole-exome and RNA sequencing to delineate their genomic architecture. For validation, we analyzed independent cohorts of primary LuADs.

RESULTS

In addition to known non-smoker-associated alterations (e.g. RET, ALK, EGFR, and ERBB2), we discovered novel fusions and recurrently mutated genes, including ATF7IP, a regulator of gene expression, that was inactivated in 5% of primary LuAD cases. We also found germline mutations at dominant familiar-cancer genes, highlighting the importance of genetic predisposition in the origin of a subset of NSK-LuADs. Furthermore, there was an over-representation of inactivating alterations at RB1, mostly through complex intragenic rearrangements, in treatment-naive EGFR-mutant LuADs. Three EGFR-mutant and one EGFR-wild-type tumors acquired resistance to EGFR-TKIs and chemotherapy, respectively, and histology on re-biopsies revealed the development of small-cell lung cancer/squamous cell carcinoma (SCLC/LuSCC) transformation. These features were consistent with RB1 inactivation and acquired EGFR-T790M mutation or FGFR3-TACC3 fusion in EGFR-mutant tumors.

CONCLUSIONS

We found recurrent alterations in LuADs that deserve further exploration. Our work also demonstrates that a subset of NSK-LuADs arises within cancer-predisposition syndromes. The preferential occurrence of RB1 inactivation, via complex rearrangements, found in EGFR-mutant tumors appears to favor SCLC/LuSCC transformation under growth-inhibition pressures. Thus RB1 inactivation may predict the risk of LuAD transformation to a more aggressive type of lung cancer, and may need to be considered as a part of the clinical management of NSK-LuADs patients.

Detection of Cross-Correlation between Gravitational Lensing and γ Rays

In recent years, many γ-ray sources have been identified, yet the unresolved component hosts valuable information on the faintest emission. In order to extract it, a cross-correlation with gravitational tracers of matter in the Universe has been shown to be a promising tool. We report here the first identification of a cross-correlation signal between γ rays and the distribution of mass in the Universe probed by weak gravitational lensing. We use data from the Dark Energy Survey Y1 weak lensing data and the Fermi Large Area Telescope 9-yr γ-ray data, obtaining a signal-to-noise ratio of 5.3. The signal is mostly localized at small angular scales and high γ-ray energies, with a hint of correlation at extended separation. Blazar emission is likely the origin of the small-scale effect. We investigate implications of the large-scale component in terms of astrophysical sources and particle dark matter emission.

Detection of CMB-Cluster Lensing using Polarization Data from SPTpol

We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes QU map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500  deg^{2} survey at the locations of roughly 18 000 clusters with richness λ≥10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8σ. The mean stacked mass of the selected sample is found to be (1.43±0.40)×10^{14}M_{⊙} which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements.

Cosmological Constraints from Multiple Probes in the Dark Energy Survey

The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically confirmed type Ia supernova light curves, the baryon acoustic oscillation feature, weak gravitational lensing, and galaxy clustering. Here we present combined results from these probes, deriving constraints on the equation of state, w, of dark energy and its energy density in the Universe. Independently of other experiments, such as those that measure the cosmic microwave background, the probes from this single photometric survey rule out a Universe with no dark energy, finding w=-0.80_{-0.11}^{+0.09}. The geometry is shown to be consistent with a spatially flat Universe, and we obtain a constraint on the baryon density of Ω_{b}=0.069_{-0.012}^{+0.009} that is independent of early Universe measurements. These results demonstrate the potential power of large multiprobe photometric surveys and pave the way for order of magnitude advances in our constraints on properties of dark energy and cosmology over the next decade.

Derivation and validation of a predictive model for the readmission of patients with diabetes mellitus treated in internal medicine departments

OBJECTIVES

We developed a predictive model for the hospital readmission of patients with diabetes. The objective was to identify the frail population that requires additional strategies to prevent readmissions at 90 days.

METHODS

Using data collected from 1977 patients in 3 studies on the national prevalence of diabetes (2015-2017), we developed and validated a predictive model of readmission at 90 days for patients with diabetes.

RESULTS

A total of 704 (36%) readmissions were recorded. There were no differences in the readmission rates over the course of the 3 studies. The hospitals with more than 500 beds showed significantly (p=.02) higher readmission rates than those with fewer beds. The main reasons for readmission were infectious diseases (29%), cardiovascular diseases (24) and respiratory diseases (14%). Readmissions directly related to diabetic decompensations accounted for only 2% of all readmissions. The independent variables associated with hospital readmission were patient's age, degree of comorbidity, estimated glomerular filtration rate, degree of disability, presence of previous episodes of hypoglycaemia, use of insulin in treating diabetes and the use of systemic glucocorticoids. The predictive model showed an area under the ROC curve (AUC) of 0.676 (95% confidence interval [95% CI] 0.642-0.709; p=.001) in the referral cohort. In the validation cohort, the model showed an AUC of 0.661 (95% CI 0.612-0.710; p=.001).

CONCLUSION

The model we developed for predicting readmissions for hospitalised patients with type 2 diabetes helps identify a subgroup of frail patients with a high risk of readmission.

Biventricular impact of mild to moderate fetal pulmonary valve stenosis

OBJECTIVES

To define the pattern of fetal echocardiographic changes associated with isolated pulmonary valve stenosis (PS) and to correlate the echocardiographic findings with neonatal outcome and the need for postnatal pulmonary valvuloplasty within the first 12 months postpartum.

METHODS

This was a prospective cohort study between January 2009 and October 2015 of 16 fetuses with isolated PS and 48 controls matched by gestational age at ultrasound examination (± 2 weeks) evaluated at the Fetal Cardiology Unit at BCNatal (Barcelona). Standard fetal ultrasound and comprehensive echocardiography, which included cardiovascular morphometric parameters, and systolic and diastolic functional and timing measurements, were performed in all cases. Baseline characteristics and perinatal outcome were retrieved from clinical records. Cases were followed up until 12 months of age, and admission to intensive care unit, days of hospitalization, need for prostaglandins and requirement for postnatal surgery were reviewed. Fetal PS cases were analyzed according to the need for postnatal pulmonary valvuloplasty.

RESULTS

The study groups were similar in terms of baseline, fetal ultrasound and perinatal characteristics. Median gestational age at diagnosis of PS was 33.4 (range, 20.0-36.5) weeks. Most cases corresponded to mild or moderate PS; only three fetuses had reversed flow in the ductus arteriosus before delivery. Six (37.5%) newborns, including all three with reversed flow in the ductus arteriosus prenatally, required postnatal pulmonary valvuloplasty. Fetuses with PS presented with larger and more globular hearts, with increased myocardial wall thickness in the third trimester. Despite preserved right ventricular (RV) ejection fraction and systolic longitudinal motion, PS cases showed increased right cardiac output and signs of diastolic dysfunction, with higher ductus venosus pulsatility index (0.72 ± 0.32 vs 0.53 ± 0.16, P = 0.004) and tricuspid E/E' ratio (7.52 ± 3.07 vs 5.76 ± 1.79, P = 0.022). In addition, fetuses with PS displayed a compensatory increase in left ventricular (LV) radial and longitudinal motion, as shown by a higher ejection fraction (79.3 ± 8.23% vs 67.6 ± 11.3%, P = 0.003) and mitral annular-plane systolic excursion (5.94 ± 1.38 vs 5.0 ± 1.22 mm, P = 0.035). Finally, fetuses requiring postnatal pulmonary valvuloplasty showed a different pattern of echocardiographic findings from those not requiring valvuloplasty, with a significantly smaller RV and pulmonary valve diameter, reduced tricuspid annular-plane systolic excursion (5.08 ± 1.59 vs 8.07 ± 1.93 mm, P = 0.028), increased LV cardiac output (340 ± 16 vs 176 ± 44 mL/min/kg, P = 0.003) and more pronounced signs of LV diastolic dysfunction (mitral E' velocity, 5.78 ± 0.90 vs 8.16 ± 1.58 cm/s, P = 0.008).

CONCLUSIONS

Fetuses with PS present with more hypertrophic, larger and more globular hearts in the third trimester of pregnancy, associated with a higher right cardiac output and impaired biventricular relaxation. In addition, signs of increased LV contraction were observed. Our data suggest that RV and LV functional parameters could be useful for predicting the need for postnatal pulmonary valvuloplasty. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Design configurations affecting flow pattern and solids accumulation in horizontal free water and subsurface flow constructed wetlands

The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW) design parameters on solids distribution, loss of hydraulic conductivity over time and hydraulic behaviour, in order to assess clogging processes in wetlands. For this purpose, an experimental plant with eight CWs was built at mesocosm scale. Each CW presented a different design characteristic, and the most common CW configurations were all represented: free water surface flow (FWS) with different effluent pipe locations, FWS with floating macrophytes and subsurface flow (SSF), and the presence of plants and specific species (Typha angustifolia and Phragmites australis) was also considered. The loss of the hydraulic conductivity of gravel was greatly influenced by the presence of plants and organic load (representing a loss of 20% and c.a. 10% in planted wetlands and an overloaded system, respectively). Cattail seems to have a greater effect on the development of clogging since its below-ground biomass weighed twice as much as that of common reed. Hydraulic behaviour was greatly influenced by the presence of a gravel matrix and the outlet pipe position. In strict SSF CW, the water was forced to cross the gravel and tended to flow diagonally from the top inlet to the bottom outlet (where the inlet and outlet pipes were located). However, when FWS was considered, water preferentially flowed above the gravel, thus losing half the effective volume of the system. Only the presence of plants seemed to help the water flow partially within the gravel matrix.

Variations of the radial recurrent artery of clinical interest

PURPOSE

The anatomy of the radial recurrent artery (RRA) is important for different clinical procedures: interventional cardiology and microsurgery of the forearm; however, few studies have analysed its morphology: number, course, relations and distribution.

METHODS

The RRA was analysed in 332 upper limbs divided into two groups: (1) normal pattern of the arterial axis of the upper limb (266 cases), (2) associated with major arterial variations (66 cases).

RESULTS

A second or accessory RRA existed in 31.2 % in group 1, and 30.3 % in group 2. In both groups, the second RRA originated from the brachial (100 %) and always (100 %) coursed behind the bicipital tendon. The accessory RRA supplied the brachioradialis, brachialis and biceps brachii muscles. The RRA in group 1, originated mostly from the radial artery (75 %), followed by radioulnar division and ulno-interosseous trunk. In group 2, the RRA arise from the brachioradial artery (65 %), or from the radial artery (in cases of ulnar or brachial artery variation). The course of the RRA behind the biceps brachii tendon was observed in 9.4 % of group 1 and in 6.1 % of group 2. The RRA supplied the brachioradialis, extensor carpi radialis longus and brevis, and supinator muscles. The RRA and accessory RRA anastomosed forming a ring around the biceps brachii tendon in 0.75 % in group 1 and in 13.6 % in group 2, the latter group having an important clinical interest.

CONCLUSIONS

The variability of the RRA may provide an advantage for microsurgical procedures of the elbow and disadvantage during transradial catheterism.

Targeting HLA class I expression to increase tumor immunogenicity

The dynamic interaction between the host immune system and growing cancer has been of central interest to the field of tumor immunology over the past years. Recognition of tumor-associated antigens (TAA) by self-HLA (human leukocyte antigen) class I-restricted CD8+ T cells is a main feature in the detection and destruction of malignant cells. The discovery and molecular characterization of TAA has changed the field of cancer treatment and introduced a new era of cancer immunotherapy aimed at increasing tumor immunogenicity and T-cell-mediated anti-tumor immunity. Unfortunately, while these new protocols of cancer immunotherapy are mediating induction of tumor-specific T lymphocytes in patients with certain malignancies, they have not yet delivered substantial clinical benefits, such as induction of tumor regression or increased disease-free survival. It has become apparent that lack of tumor rejection is the result of immune selection and escape by tumor cells that develop low immunogenic phenotypes. Substantial experimental data support the existence of a variety of different mechanisms involved in the tumor escape phase, including loss or downregulation of HLA class I antigens. These alterations could be caused by regulatory ('soft') or by structural/irreversible ('hard') defects. On the basis of the evidence obtained from experimental mouse cancer models and metastatic human tumors, the structural defects underlying HLA class I loss may have profound implications on T-cell-mediated tumor rejection and ultimately on the outcome of cancer immunotherapy. Strategies to overcome this obstacle, including gene therapy to recover normal expression of HLA class I genes, require consideration. In this review, we outline the importance of monitoring and correction of HLA class I alterations during cancer development and immunotherapy.

Complex aortic coarctation and PHACE syndrome

In PHACE syndrome, the acronym PHACE stands for the association of posterior fossa malformations, cervicofacial hemangiomas, arterial anomalies, coarctation and eye anomalies. We report our findings in four patients with this syndrome, in whom it was characterized by complex aortic coarctation that required not only preoperative echocardiographic investigation, but also the use of techniques such as magnetic resonance imaging and angiography. Surgical treatment was also complex. Prognosis in this condition depends primarily on cardiovascular and cerebral artery complications associated with the syndrome.

Percutaneous treatment of atrial septal defects, muscular ventricular septal defects and patent ductus arteriosus in infants under one year of age

Amplatzer devices are used for the percutaneous closure of ostium secundum atrial septal defects, muscular ventricular septal defects and patent ductus arteriosus. However, very little experience has been gained in using these devices in infants under 1 year of age. Between January 2001 and January 2008, 22 symptomatic infants aged under 1 year underwent percutaneous treatment: three had an ostium secundum atrial septal defect, 15 had patent ductus arteriosus, and four had a muscular ventricular septal defect. All the procedures were completed successfully. No immediate or medium-term complications were observed. Closure of these types of defect using an Amplatzer device in infants under 1 year of age, who would otherwise require surgery, is a safe and effective procedure.

Prenatal expression of interleukin 1beta and interleukin 6 in the rat pituitary gland

It is known that interleukin 1beta (IL-1beta) and interleukin 6 (IL-6) are expressed post-natally in normal and tumoral cells in the anterior pituitary, and that they play a role in both the liberation of different hormones and in the growth, proliferation and tumor formation of the pituitary gland. However, their expression and role during embryonic and fetal development remain unknown. We have performed an immunocytochemistry study of prenatal expression and distribution of IL-1beta and IL-6 in isolated embryonic rat Rathke's pouch prior to birth, more specifically between 13.5 and 19.5 days p.c. Western-blot analysis carried out on 19.5-day p.c. embryos showed positive immunolabelling for IL-1beta and IL-6. These interleukins were initially expressed simultaneously in the rostral and ventral portions of Rathke's pouch in 15.5-day p.c. embryos, and this expression progressed caudodorsally in later developmental stages, extending to most of the hypophysis before birth. The number of cells expressing these interleukins increased throughout this period: 48.22% of anterior pituitary cells expressed IL-6 in 19.5-day embryos, whilst IL-1beta was positive in 39.8% of the cells. Moreover, we have demonstrated that some adenohypophyseal cells co-express both interleukins. Such findings represent the first step towards an understanding of the physiological role of these interleukins in anterior pituitary development.

Dysfunctional AMPK activity, signalling through mTOR and survival in response to energetic stress in LKB1-deficient lung cancer

LKB1, mutated in Peutz-Jeghers and in sporadic lung tumours, phosphorylates a group of protein kinases named AMP-activated protein kinase (AMPK)-related kinases. Among them is included the AMPK, a sensor of cellular energy status. To investigate the relevance of LKB1 in lung carcinogenesis, we study several lung cancer cells with and without LKB1-inactivating mutations. We report that LKB1-mutant cells are deficient for AMPK activity and refractory to mTOR inhibition upon glucose depletion but not growth-factor deprivation. The requirement for wild-type LKB1 to properly activate AMPK is further demonstrated in genetically modified cancer cells. In addition, LKB1-deficient lung primary tumours had diminished AMPK activity, assessed by complete absence or low level of phosphorylation of its critical substrate, acetyl-CoA carboxylase. We also demonstrate that LKB1 wild-type cells are more resistant to cell death upon glucose withdrawal than their mutant counterparts. Finally, modulation of AMPK activity did not affect PI3K/AKT signalling, an advantage for the potential use of AMPK as a target for cancer therapy in LKB1 wild-type tumours. Thus, sustained abrogation of cell energetic checkpoint control, through alterations at key genes, appear to be an obligatory step in the development of some lung tumours.

Stochastic model to forecast ground-level ozone concentration at urban and rural areas

Stochastic models that estimate the ground-level ozone concentrations in air at an urban and rural sampling points in South-eastern Spain have been developed. Studies of temporal series of data, spectral analyses of temporal series and ARIMA models have been used. The ARIMA model (1,0,0) x (1,0,1)24 satisfactorily predicts hourly ozone concentrations in the urban area. The ARIMA (2,1,1) x (0,1,1)24 has been developed for the rural area. In both sampling points, predictions of hourly ozone concentrations agree reasonably well with measured values. However, the prediction of hourly ozone concentrations in the rural point appears to be better than that of the urban point. The performance of ARIMA models suggests that this kind of modelling can be suitable for ozone concentrations forecasting.

Contrast media: future aspects

In spite of the dramatic development in CT, there was no major breakthrough in the iodinated contrast media development. New agents based on hybrid between MRI and CT compounds may be a new innovative alternative. This new approach may also open new indications such as radiotherapy.

[Aortic origin of the left pulmonary artery in an infant with Fallot's tetralogy]

We report the case of a male neonate who had a prenatal diagnosis of Fallot's tetralogy. He presented with respiratory distress during the second week of life. Chest x-ray showed an enlarged right ventricle and pulmonary edema. Echocardiography demonstrated characteristic features of Fallot's tetralogy. However, cardiac catheterization disclosed that, in this case of Fallot's tetralogy, the left pulmonary artery had an anomalous origin in the ascending aorta. At 23 days of age, the patient underwent total surgical correction of the defects, during which a direct anastomosis was employed without conduit placement. 10 days later, he was discharged. We present the results of a literature review of the epidemiological, physiopathological, clinical, diagnostic, and surgical characteristics of this rare condition.

[Ductus arteriosus patency with stenting in critical pulmonary stenosis and pulmonary atresia with intact interventricular septum]

We report our experience with stenting of the ductus arteriosus in three neonates. Two patients had pulmonary atresia with an intact interventricular septum and one had critical pulmonary stenosis. Radiofrequency ablation was used to open the atretic pulmonary valve in two patients. In all three patients implanting a stent avoided the need for surgical creation of a Blalock-Taussig shunt. In two patients the procedure was scheduled as elective surgery, and in one it was done as an emergency procedure. Ductus arteriosus stenting is an alternative to palliative cardiac surgery.

Analyses of ozone in urban and rural sites in Málaga (Spain)

Ozone concentrations were measured at two (urban and a rural) sites near the city of Málaga (Spain). The aim of this study was to determine the daily, monthly and seasonal variation patterns of ozone concentrations at both sites and to study the possible regional influences. The daily variations mostly have the usual features with the afternoon maximum and the night minimum being more pronounced in the urban area. The average monthly concentrations throughout the year start to increase in March reaching their maximum values in July for the urban site. However, in the rural area, the monthly variations are smaller reaching their maximum value in June. The hourly evolution of the ozone concentrations in both sampling sites is well defined in spring and summer and not so well defined in autumn and winter. Taking into account the four seasons, the rural concentrations are higher than the urban ones. Summer is the season when there are similar concentrations at both sampling sites. Average hourly summer afternoon ozone for the hours 12:00-20:00 LST exceeded the 110 microg m(-3) European Union guidelines for human health for 8 h ozone exposure at the urban and rural sites.

Expression of the mu-opioid receptor in the anterior pituitary gland is influenced by age and sex

To analyze whether opioids are able to modulate endocrine regulation by acting directly on rat pituitary cells, an immunohistochemical study of micro-opioid receptor expression in these cells was performed, with attention given to the analysis of potential age- and sex-related variations in receptor expression patterns. In both sexes, the micro-opioid receptor was detected in the pituitary pars distalis. However, significant age-related differences were observed. Both in male and female rats, the percentage of micro-opioid receptor-expressing cells decreased significantly from postnatal week one through the 24 months of our study. Interestingly, pituitary cells containing the micro-opioid receptor were significantly more numerous in male than in female, with exception of the pre-pubertal phase and old rats. According to two-way analysis of variance, the gender-related differences in micro-receptor expression were independent of age-related variations. Thus, without excluding hypothalamic actions, our results suggest that opioids may exert their endocrine function by acting directly on pituitary cells.

Dopaminergic modulation of nNOS expression in the pituitary gland of male rat

Nitric oxide is an unconventional transmitter since it is not transported and released by exocytosis. In the pituitary gland, nitric oxide is locally synthesised by gonadotroph and folliculo-stellate cells. Dopamine, the principal central inhibitory signal in prolactin release, may exert its inhibitory effects by stimulation of nitric oxide production. However, the effects of dopaminergic modulation on nitric oxide-producing pituitary cells have not been analysed. Therefore, we examined the effects of intraventricular administration of the dopamine antagonist haloperidol (40 microg) on the pituitary expression of neuronal nitric oxide synthase (nNOS) in male adult rats. In untreated and control animals, nNOS-positive cells were very similar. Two types of nNOS-positive cells appeared in the pars distalis: round or polygonal cells and stellate cells. Although some isolated cells were found, the nNOS-positive cells commonly appeared grouped in clusters close to blood vessels. nNOS immunoreactivity appeared as a uniform staining throughout the cytoplasm, including cell prolongations. The number and size of nNOS-expressing cells in the pituitary gland decreased significantly after treatment with haloperidol (p<0.01). To evaluate the potential direct effect of dopamine on pituitary cells, pituitary monolayer cultures were treated with dopamine during a time-course of 12 h. Our in vitro studies revealed that dopamine increases the percentage of nNOS-positive cells and augments cellular area (p<0.05). These results demonstrate that: (1) treatment of rats in vivo with a dopamine antagonist significantly decreases expression of nNOS in the pituitary and (2) in vitro dopamine exerts a direct effect on pituitary cultures by increasing nNOS-positive cells. Thus, these findings suggest that dopamine may function as a physiological stimulator of nNOS expression in the rat pituitary gland.

Postnatal differentiation of the immunohistochemical expression of aromatase P450 in the rat pituitary gland

At our laboratory, we have recently demonstrated the immunohistochemical expression of aromatase P450 in the pituitary glands of adult rats; this expression was seen to be sex-dependent. In order to determine whether the changes in the expression of the enzyme are related to changes in the gonadal sphere and whether the expression of the enzyme is related to the postnatal differentiation of hypophyseal cytology, in the present work we performed an immunohistochemical study in the rat pituitary gland from birth to old age. The immunohistochemical reaction to aromatase was evident and very generalized at 7 days after birth, with no large differences between the male and female animals. At 14 days the immunohistochemical reaction was decreased in the females, with no changes in the males. At 17 days, aromatase immunoreactivity in the pituitary glands of female rats was very weak whereas the males showed large numbers of reactive cells. These observations were further pronounced at 21 days and 2 months of life. At 24 months, the immunoreactivity found in the pituitary glands of the male rats had almost completely disappeared. Our results show that a postnatal differentiation in the immunohistochemical expression of aromatase occurs; this is tightly linked to sexual activity and is lost in old age. This suggests that hypophyseal aromatase would be related to the mechanisms of action of gonadal steroids on hypophyseal differentiation and secretion.