Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

GABA Receptors in the Medial Preoptic Area Modulate the Onset of Oestradiol-Induced Maternal Behaviour in Hysterectomised-Ovariectomised, Pregnant Rats

We studied the participation of GABA neurotransmission in the medial preoptic area (mPOA) with respect to the onset of the pup retrieval response and nest building. Pregnant female rats were implanted with bilateral cannulae in the mPOA on day 12 of pregnancy and, on day 16, the females were hysterectomised and ovariectomised and given 200 μg/kg of oestradiol benzoate. Two days later, the females received one of the following intracerebral drug treatments: GABA_B agonist baclofen (200 ng); GABA_B antagonist phaclofen (1 μg); GABA_A antagonist bicuculline (60 ng); or physiological saline. Five minutes after intracerebral infusion, three foster pups were introduced into the females' home cage. The subjects were observed for pup grouping (retrieval) during 15 min, after which the pups were left with the female. During the next 12 h, an observation was made every 1 h to determine whether the pups had been grouped (retrieved) or not. The GABA_B agonist baclofen reduced the proportion of females retrieving pups from 4 to 8 h following pup introduction. By contrast, both the GABA_A antagonist bicuculline and the GABA_B antagonist phaclofen enhanced the proportion of females retrieving pups during the first 3 h of observation. The latency to pup retrieval in subjects treated with the GABA_B agonist baclofen was significantly longer than that in subjects given any of the antagonists. All females built a nest but baclofen reduced nest quality. These data show that activation of GABA_B receptors in the mPOA has an inhibitory effect on basic maternal behaviours, whereas blockade of either the GABA_A or GABA_B receptor facilitates pup retrieval. It is possible that reduced GABAergic tone in the mPOA is a key element in the initiation of maternal behaviours in postparturient rats.

Influence of thyroid disorders on the kidney expression and plasma activity of aminopeptidase A

OBJECTIVE

Thyroid disorders may affect blood pressure and renal function modifying factors of the plasmatic and kidney renin-angiotensin system such as aminopeptidase A (AP A) that metabolizes angiotensin II to angiotensin III. We investigated the expression of AP A in the kidney, as well as its enzymatic activity in the plasma of euthyroid, hyperthyroid, and hypothyroid adult male rats.

METHODS

Hyperthyroidism was induced by daily subcutaneous injections of tetraiodothyronine. Hypothyroid rats were obtained by administration of methimazole in drinking water. Expression of AP A was determined by Western blot analysis. Plasma AP A activity was measured fluorometrically using glutamyl-β-naphthylamide as substrate.

RESULTS

While hyperthyroid rats exhibited lower levels of plasma AP A activity than controls, the kidney of hyperthyroid animals expressed significantly higher AP A than controls and hypothyroid animals.

CONCLUSIONS

A discrepancy between the high expression of AP A in kidney of hyperthyroid rats and the low activity of AP A measured in plasma and kidney of hyperthyroid animals was found. The posttranslational influence of environmental biochemical factors may be in part responsible for that divergence.

Rescuing prefrontal cAMP-CREB pathway reverses working memory deficits during withdrawal from prolonged alcohol exposure

Both human and animal studies indicate that alcohol withdrawal following chronic alcohol consumption (CAC) impairs many of the cognitive functions which rely on the prefrontal cortex (PFC). A candidate signaling cascade contributing to memory deficits during alcohol withdrawal is the protein kinase A (PKA)/cAMP-responsive element binding (CREB) cascade, although the role of PKA/CREB cascade in behavioral and molecular changes during sustained withdrawal period remains largely unknown. We demonstrated that 1 week (1W) or 6 weeks (6W) withdrawal after 6-month CAC impairs working memory (WM) in a T-maze spontaneous alternation task and reduces phosphorylated CREB (pCREB) in the PFC but not the dorsal CA1 region (dCA1) of the hippocampus compared with CAC and water conditions. In contrast, both CAC-unimpaired and withdrawn-impaired mice exhibited decreased pCREB in dCA1 as well as reduced histone H4 acetylation in PFC and dCA1, compared with water controls. Next, we showed that enhancing CREB activity through rolipram administration prior to testing improved WM performance in withdrawn mice but impaired WM function in water mice. In addition, WM improvement correlates positively with increased pCREB level selectively in the PFC of withdrawn mice. Results further indicate that direct infusion of the PKA activator (Sp-cAMPS) into the PFC significantly improves or impairs, respectively, WM performance in withdrawn and water animals. In contrast, Sp-cAMPS had no effect on WM when infused into the dCA1. Collectively, these results provide strong support that dysregulation of PKA/CREB-dependent processes in prefrontal neurons is a critical molecular signature underlying cognitive decline during alcohol withdrawal.

Tunable phonon polaritons in atomically thin van der Waals crystals of boron nitride

van der Waals heterostructures assembled from atomically thin crystalline layers of diverse two-dimensional solids are emerging as a new paradigm in the physics of materials. We used infrared nanoimaging to study the properties of surface phonon polaritons in a representative van der Waals crystal, hexagonal boron nitride. We launched, detected, and imaged the polaritonic waves in real space and altered their wavelength by varying the number of crystal layers in our specimens. The measured dispersion of polaritonic waves was shown to be governed by the crystal thickness according to a scaling law that persists down to a few atomic layers. Our results are likely to hold true in other polar van der Waals crystals and may lead to new functionalities.

Role of corticosteroid binding globulin in the fast actions of glucocorticoids on the brain

Corticosteroid binding globulin (CBG) is a glycoprotein synthesized in liver and secreted in the blood where it binds with a high affinity but low capacity glucocorticoid hormones, cortisol in humans and corticosterone in laboratory rodents. In mammals, 95% of circulating glucocorticoids are bound to either CBG (80%) or albumin (15%) and only the 5% free fraction is able to enter the brain. During stress, the concentration of glucocorticoids rises significantly and the free fraction increases even more because CBG becomes saturated. However, glucocorticoids unbound to CBG are cleared from the blood more quickly. Our studies on mice totally devoid of CBG (Cbg k.o.) showed that during stress these mutant mice display a lower rise of glucocorticoids than the wild-type controls associated with altered emotional reactivity. These data suggested that CBG played a role in the fast actions of glucocorticoids on behavior. Further analyses demonstrated that stress-induced memory retrieval impairment, an example of the fast action of glucocorticoids on the brain is abolished in the Cbg k.o. mice. This effect of stress on memory retrieval could be restored in the Cbg k.o. mice by infusing corticosterone directly in the hippocampus. The mechanisms explaining these effects involved an increased clearance but no difference in corticosterone production. Thus, CBG seems to have an important role in maintaining in blood a glucocorticoid pool that will be able to access the brain for the fast effects of glucocorticoids.

Ultrafast and nanoscale plasmonic phenomena in exfoliated graphene revealed by infrared pump-probe nanoscopy

Pump-probe spectroscopy is central for exploring ultrafast dynamics of fundamental excitations, collective modes, and energy transfer processes. Typically carried out using conventional diffraction-limited optics, pump-probe experiments inherently average over local chemical, compositional, and electronic inhomogeneities. Here, we circumvent this deficiency and introduce pump-probe infrared spectroscopy with ∼ 20 nm spatial resolution, far below the diffraction limit, which is accomplished using a scattering scanning near-field optical microscope (s-SNOM). This technique allows us to investigate exfoliated graphene single-layers on SiO2 at technologically significant mid-infrared (MIR) frequencies where the local optical conductivity becomes experimentally accessible through the excitation of surface plasmons via the s-SNOM tip. Optical pumping at near-infrared (NIR) frequencies prompts distinct changes in the plasmonic behavior on 200 fs time scales. The origin of the pump-induced, enhanced plasmonic response is identified as an increase in the effective electron temperature up to several thousand Kelvin, as deduced directly from the Drude weight associated with the plasmonic resonances.

Targeting Chk2 improves gastric cancer chemotherapy by impairing DNA damage repair

Our results demonstrate that the addition of cisplatin after paclitaxel-induced mitotic arrest was more effective than individual treatment on gastric adenocarcinoma cells (MKN45). However, the treatment did not induce benefits in cells derived from lymph node metastasis (ST2957). Time-lapse microscopy revealed that cell death was caused by mitotic catastrophe and apoptosis induction, as the use of the caspase inhibitor z-VAD-fmk decreased cell death. We propose that the molecular mechanism mediating this cell fate is a slippage suffered by these cells, given that our Western blot (WB) analysis revealed premature cyclin B degradation. This resulted in the cell exiting from mitosis without undergoing DNA damage repair, as demonstrated by the strong phosphorylation of H2AX. A comet assay indicated that DNA repair was impaired, and Western blotting showed that the Chk2 protein was degraded after sequential treatment (paclitaxel-cisplatin). Based on these results, the modulation of cell death during mitosis may be an effective strategy for gastric cancer therapy.

Electronic and plasmonic phenomena at graphene grain boundaries

Graphene, a two-dimensional honeycomb lattice of carbon atoms of great interest in (opto)electronics and plasmonics, can be obtained by means of diverse fabrication techniques, among which chemical vapour deposition (CVD) is one of the most promising for technological applications. The electronic and mechanical properties of CVD-grown graphene depend in large part on the characteristics of the grain boundaries. However, the physical properties of these grain boundaries remain challenging to characterize directly and conveniently. Here we show that it is possible to visualize and investigate the grain boundaries in CVD-grown graphene using an infrared nano-imaging technique. We harness surface plasmons that are reflected and scattered by the graphene grain boundaries, thus causing plasmon interference. By recording and analysing the interference patterns, we can map grain boundaries for a large-area CVD graphene film and probe the electronic properties of individual grain boundaries. Quantitative analysis reveals that grain boundaries form electronic barriers that obstruct both electrical transport and plasmon propagation. The effective width of these barriers (∼10-20 nm) depends on the electronic screening and is on the order of the Fermi wavelength of graphene. These results uncover a microscopic mechanism that is responsible for the low electron mobility observed in CVD-grown graphene, and suggest the possibility of using electronic barriers to realize tunable plasmon reflectors and phase retarders in future graphene-based plasmonic circuits.

Human Papillomavirus: Mini-review and Collateral Expected Benefits of the Vaccine

Cervical neoplasia is the second leading cause of neoplastic death in Latin America. It is generally accepted that all cervical carcinomas have at least one high risk Human Papillomavirus (HPV). Due to the causal relationship of specific HPV types and cervical cancer and its role as precursor of skin lesions it is important to identify the involved genotype. HPV, as other tumor-viruses, induces oncogenesis by manipulating an array of different cellular pathways, which leads to immortalization and proliferation of the infected cells by disrupting the mitotic checkpoint upon infection of the host cell. Actually the role of the immune response in the development of cervical cancer is unknown as is the relationship between the type and level of expression of messenger RNA (mRNA) of interferon gamma (IFN-γ), transforming growth factor beta 1 (TGF-β1) and interleukin (IL)-4 in the cervical microenvironment within each of the stages of carcinogenesis with the HPV genotype causing the infection. An average annual cost to treat cervical cancer is U.S. $ 10,283 per patient. Taking into account the World Population Prospects: The 2010 Revision, in ten years the accumulated cases of cervical cancer might be 3,286,534, thus making a total budget of U.S. $ 33,795.4 million to treat all women. Universal vaccination against HPV might result in extended benefits as the decrease in mouth and oropharynx cancers as well as the reduction in health cost for the attendance of several neoplasias. Nepal Journal of Obstetrics and Gynaecology / Vol 8 / No. 1 / Issue 15 / Jan- June, 2013 / 4-9 DOI: http://dx.doi.org/10.3126/njog.v8i1.8852

Analysis of exosome release and its prognostic value in human colorectal cancer

A significant proportion of extracellular nucleic acids in plasma circulate highly protected in tumor-specific exosomes, but it is unclear how the release of exosomes is modulated in carcinogenesis. We quantified by cytometry exosomes in plasma of 91 colorectal cancer patients to evaluate their potential as a tumor indicator and their repercussions on diagnosis and prognosis. We examined the involvement of TSAP6, a TP53-regulated gene involved in the regulation of vesicular secretion, in levels of circulating exosomes in plasma of colorectal patients and in HCT116 TP53-(wild-type and null) human colorectal cancer cell lines. The fraction of exosomes in cancer patients was statistically higher than in healthy controls (mean rank ¼ 53.93 vs. 24.35). High levels of exosomes in plasma of patients correlated with high levels of carcino-embryonic antigen (P ¼ 0.029) and with poorly differentiated tumors (P ¼ 0.039) and tended to have shorter overall survival than patients with low levels (P ¼ 0.056). Release of exosomes did not correlate with TSAP6 expression; and regulation of TSAP6 by TP53 was not shown either in tumor samples or in HCT116 cell lines. Although it was not suggested that the TP53/TSAP6 pathway regulates the release of exosomes into the plasma of colorectal cancer patients, the level of circulating exosomes may be used as a tumor indicator, because it correlates with poor prognosis parameters and shorter survival.

The Physical Chemistry of Mass-Independent Isotope Effects and Their Observation in Nature

Historically, the physical chemistry of isotope effects and precise measurements in samples from nature have provided information on processes that could not have been obtained otherwise. With the discovery of a mass-independent isotopic fractionation during the formation of ozone, a new physical chemical basis for isotope effects required development. Combined theoretical and experimental developments have broadened this understanding and extended the range of chemical systems where these unique effects occur. Simultaneously, the application of mass-independent isotopic measurements to an extensive range of both terrestrial and extraterrestrial systems has furthered the understanding of events such as solar system origin and evolution and planetary atmospheric chemistry, present and past.

Infrared nanoscopy of dirac plasmons at the graphene-SiO₂ interface

We report on infrared (IR) nanoscopy of 2D plasmon excitations of Dirac fermions in graphene. This is achieved by confining mid-IR radiation at the apex of a nanoscale tip: an approach yielding 2 orders of magnitude increase in the value of in-plane component of incident wavevector q compared to free space propagation. At these high wavevectors, the Dirac plasmon is found to dramatically enhance the near-field interaction with mid-IR surface phonons of SiO(2) substrate. Our data augmented by detailed modeling establish graphene as a new medium supporting plasmonic effects that can be controlled by gate voltage.

EPAS1 mRNA in plasma from colorectal cancer patients is associated with poor outcome in advanced stages

The presence of free nucleic acids in plasma has been detected in cancer patients and is associated with poor prognosis. In the present study, the mRNA levels of three genes (EPAS1, KIAA0101 and UBE2D3) in plasma from colorectal cancer patients were analyzed. These genes were selected from a previous study of genomic profiles, discriminating between healthy controls and colorectal cancer patients. mRNA levels were analyzed by real-time PCR in the plasma of 154 patients with colorectal cancer. The association of plasma mRNA levels with clinicopathological parameters and patient survival were analyzed. High levels of EPAS1 in the plasma were associated with patients aged over 50 years, relapse of disease and patient mortality. When patients were divided into two groups, early (I and II) and advanced (III and IV) stages, an association was observed between high levels of EPAS1 mRNA and worse disease-free and overall survival in advanced stages. The expression of KIAA0101 and UBE2D3 was not associated with poor prognosis. Thus, our results suggest that EPAS1 mRNA levels may be an indicator of poor prognosis in colorectal cancer patients at advanced stages, obtained by a non-invasive method.

Detection of oxygen isotopic anomaly in terrestrial atmospheric carbonates and its implications to Mars

The debate of life on Mars centers around the source of the globular, micrometer-sized mineral carbonates in the ALH84001 meteorite; consequently, the identification of Martian processes that form carbonates is critical. This paper reports a previously undescribed carbonate formation process that occurs on Earth and, likely, on Mars. We identified micrometer-sized carbonates in terrestrial aerosols that possess excess (17)O (0.4-3.9‰). The unique O-isotopic composition mechanistically describes the atmospheric heterogeneous chemical reaction on aerosol surfaces. Concomitant laboratory experiments define the transfer of ozone isotopic anomaly to carbonates via hydrogen peroxide formation when O(3) reacts with surface adsorbed water. This previously unidentified chemical reaction scenario provides an explanation for production of the isotopically anomalous carbonates found in the SNC (shergottites, nakhlaites, chassignites) Martian meteorites and terrestrial atmospheric carbonates. The anomalous hydrogen peroxide formed on the aerosol surfaces may transfer its O-isotopic signature to the water reservoir, thus producing mass independently fractionated secondary mineral evaporites. The formation of peroxide via heterogeneous chemistry on aerosol surfaces also reveals a previously undescribed oxidative process of utility in understanding ozone and oxygen chemistry, both on Mars and Earth.

Characterization of the single particle mixing state of individual ship plume events measured at the Port of Los Angeles

Ship emissions contribute significantly to gaseous and particulate pollution worldwide. To better understand the impact of ship emissions on air quality, measurements of the size-resolved chemistry of individual particles in ship emissions were made at the Port of Los Angeles using real-time, single-particle mass spectrometry. Ship plumes were identified through a combination of ship position information and measurements of gases and aerosol particles at a site 500 m from the center of the main shipping channel at the Port of Los Angeles. Single particles containing mixtures of organic carbon, vanadium, and sulfate (OC-V-sulfate) resulted from residual fuel combustion (i.e., bunker fuel), whereas high quantities of fresh soot particles (when OC-V-sulfate particles were not present) represented distinct markers for plumes from distillate fuel combustion (i.e., diesel fuel) from ships as well as trucks in the port area. DC-V-sulfate particles from residual fuel combustion contained significantly higher levels of sulfate and sulfuric acid than plume particles containing no vanadium. These associations may be due to vanadium (or other metals such as iron) in the fuel catalyzing the oxidation of S0(2) to produce sulfate and sulfuric acid on these particles. Enhanced sulfate production on OC-V-sulfate ship emission particles would help explain some of the higher than expected sulfate levels measured in California compared to models based on emissions inventories and typical sulfate production pathways. Understanding the overall impact of ships emissions is critical for controlling regional air quality in the many populated coastal regions of the world.

14 DEEP INTRAUTERINE FIXED-TIME ARTIFICIAL INSEMINATION USING SEXED SEMEN IN HOLSTEIN HEIFERS

Flow sorting cytometry has been shown to repeatedly produce viable sexed sperm at a level necessary for commercialization. Previous reports have shown that pregnancies rates were lower using sexed semen than commercial nonsexed semen. Sperm concentration, acrosome activation, and time to ovulation are some factors explaining the low conception. The objective of the present study was to compare pregnancy rates using sexed semen (3 × 106 sperm) deposited in different locations of the bovine uterus (body v. horn) and inseminated (AI) at 2 different times (52 h v. 58 h after progesterone intravaginal device removal). Holstein heifers, between 15 to 18 mo of age and a body condition score 3.05 ± 0.22 were used. All heifers were evaluated by transrectal ultrasonography to determine ovarian structures (284/357, 79.5% had a CL). On Day 0, all heifers received an intravaginal progesterone (P4) device (1.9 g of P4, CIDR, Pfizer, Buenos Aires, Argentina) plus 70 μg of D-cloprostenol (Bioprost, Biotay, Argentina) i.m. and 2 mg of estradiol benzoate (EB, Syntex SA, Buenos Aires, Argentina). On Day 8, CIDR devices were removed and heifers received 150 μg of D-cloprostenol i.m. at the same time. On Day 9, all heifers received 1 mg of EB i.m. and were randomly allocated in 4 different groups (2 × 2 factorial): group Body-52 h, AI in the body of the uterus at 52 h (n = 98); group Body-58 h: AI in the body of the uterus at 58 h (n = 104); group Horn-52 h: AI in the ipsilateral horn of the ovulatory follicle (detected by ultrasonography) at 52 h (n = 90) and group Horn-58 h: AI in the ipsilateral horn to the ovulatory follicle at 58 h (n = 65). All heifers were inseminated with only one dose of sexed semen. At time of AI an ultrasound examination was done to determine the size and the location of the preovulatory follicle. AI was done by a single inseminator using a traditional AI gun, and an embryo transfer gun (ET sheath, SBS Cryotec SA, Argentina) was used for deep AI. Pregnancy diagnosis was evaluated by transrectal ultrasonography using a 7.5-MHz transducer (Mindray 6600) 30 days after AI. Data were analyzed by logistic regression. Sixty percent of the preovulatory follicles were on the right ovary, and there were no differences between the sizes of the preovulatory follicle among groups (overall mean ± SEM: 15.5 ± 1.0 mm). Although pregnancy rates did not differ between horn (64/155, 41.2%) and body (70/202, 34.3%; P < 0.1) inseminations and between 52 h (67/188, 36.7% and 58 h (67/169, 39.6%), pregnancy rates were higher (P < 0.05) in heifers inseminated in the horn at 58 h (32/65, 49.2%) than those inseminated in the body at 58 h (35/104, 33.6%) and tended (P < 0.09) to be higher than heifers inseminated in the horn at 52 h (32/90, 35.5%) and in the body at 52 h (35/98, 35.7%). Fixed-time artificial insemination using ultrasonography and deep insemination could contribute to enhanced pregnancy rates using sexed semen in Holstein heifers. This research was done with the support of ADECO SA, SBS Cryo Tec SA.

Impact Features on Stardust: Implications for Comet 81P/Wild 2 Dust

Particles emanating from comet 81P/Wild 2 collided with the Stardust spacecraft at 6.1 kilometers per second, producing hypervelocity impact features on the collector surfaces that were returned to Earth. The morphologies of these surprisingly diverse features were created by particles varying from dense mineral grains to loosely bound, polymineralic aggregates ranging from tens of nanometers to hundreds of micrometers in size. The cumulative size distribution of Wild 2 dust is shallower than that of comet Halley, yet steeper than that of comet Grigg-Skjellerup.

Comet 81P/Wild 2 Under a Microscope

The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

Adolescents carrying a missense mutation in the CART gene exhibit increased anxiety and depression

A Leu34Phe mutation in the cocaine- and amphetamine-regulated transcript (CART) gene has been associated with severe early-onset obesity in an affected family. It has been shown that, in a cell culture system, the mutation resulted in altered CART peptide levels, and animal studies suggest that CART is involved in anxiety as well. The availability of the affected family allowed for testing of anxiety and other traits in humans carrying a mutation in CART gene. This study shows that a small group of adolescents with the mutation exhibit higher anxiety and depression scores than control subjects.

Cocaine- and amphetamine-regulated transcript peptide levels in blood exhibit a diurnal rhythm: regulation by glucocorticoids

Cocaine- and amphetamine-regulated transcript (CART) peptides are novel neurotransmitters that are implicated in several physiological functions such as control of feeding behavior, drug reward, sensory processing, stress, and development. Although a majority of studies have examined the role of CART in the brain, less is known about its function in the periphery. Therefore, the goals of this study were to examine the levels and species of CART peptides in blood, to determine whether they undergo diurnal rhythms, and to elucidate their sources and regulatory factors. RIA showed that CART peptides are present in the blood of rats and monkeys and that they exhibit a diurnal variation. Western blotting confirmed the pattern of diurnal variation in rats and, additionally, showed that CART immunoreactivity was due to a single predominant fragment with an apparent molecular weight in the range of the active CART 55-102 peptide. Adrenalectomy caused a 70% reduction in CART peptide levels in rat blood, and this was reversed by corticosterone replacement. CART levels paralleled glucocorticoid levels in rat and monkey blood. Control of CART levels by corticosterone suggests the possibility that CART peptides in blood may be influenced by hypothalamic-pituitary-adrenal interactions and that they may play a role in glucocorticoid-related processes such as stress.

Prognostic significance of the allelic loss of the BRCA1 gene in colorectal cancer

BACKGROUND

Survival at the intermediate stage of colorectal cancer (CRC) is less predictable than in the early and advanced stages. Several genetic markers possibly involved in growth and progression of CRC can be used for prognosis.

AIMS

This study investigated the proportion of allelic loss (loss of heterozygosity (LOH)) at the BRCA1 locus in sporadic CRC and its value in patient prognosis.

PATIENTS AND METHODS

A total of 314 patients were investigated for LOH at the BRCA1 locus using polymerase chain reaction by means of three intragenic polymorphic microsatellite markers. Allelic losses were compared with clinicopathological characteristics of patients, recurrence rate, disease free survival (DFS), and overall survival.

RESULTS

Twenty six patients were excluded because of microsatellite instability. Of the remaining 288 cases, 244 (84.7%) were informative, with 97 (39.8%) patients bearing BRCA1 LOH. Recurrence rate was higher in patients with LOH (p=0.0003), and DFS was 73.3% (SEM 5.7) at five years in patients without LOH, and 49.2% (7.1) in cases with positive allelic loss (p=0.0004). Retention of alleles at the BRCA1 locus was associated with a favourable DFS in stages I and II (p<0.05). The presence of LOH was also significantly associated with short overall survival (p=0.02). Multivariate analysis in the complete series showed that stage (p=0.006) and lymph node metastases (> or =4 nodes, p=0.0001; 1-3 nodes, p=0.038) were independent prognostic factors. However, multivariate study by stages revealed that BRCA1 LOH was an independent prognostic factor in stages I and II (p=0.001).

CONCLUSIONS

BRCA1 LOH is a molecular alteration present in CRC, with unfavourable repercussions for overall survival, that could be considered as an outstanding independent prognostic factor in stages I and II.

CART promoter CRE site binds phosphorylated CREB

It has been shown previously that: CART (cocaine- and amphetamine-regulated transcript) mRNA is tightly regulated in brain; protein kinase A (PKA) is involved in CART expression in GH3 cells; and a cyclic AMP-responsive element (CRE) site is present in the proximal promoter region of the CART gene. Thus, the goal of this study was to test if CRE binding protein (CREB) can bind to the consensus CRE site and if phosphorylation of CREB occurs in GH3 cells under conditions of enhanced CART gene expression. Electromobility shift assays showed that a 27-bp oligonucleotide containing the CART CRE site was indeed bound by nuclear factors. Western blotting showed that incubation of GH3 cells with forskolin, which enhances CART mRNA expression, caused an increase in phosphorylated CREB (P-CREB) levels. Supershift analyses indicated that the CART CRE oligo/protein complex interacted with a P-CREB antibody. Taken together, these data indicate that P-CREB is a likely regulator of CART expression in GH3 cells.

Detection of epithelial tumour RNA in the plasma of colon cancer patients is associated with advanced stages and circulating tumour cells

BACKGROUND

Although circulating tumour DNA has been detected in patients with different types of cancer, little is known of free RNA in cancer patients.

AIMS

We investigated the presence of RNA from epithelial tumours in plasma from patients with colorectal carcinomas, and its correlation with tumour characteristics and circulating tumour cells.

METHODS

beta-actin mRNA was analysed to assess the viability of plasma RNA in samples from 53 patients with colonic cancer and 25 controls. Subsequently, nested primers were used to detect the presence of cytokeratin 19 (CK19) and carcinoembryonic antigen (CEA) RNA in the same samples. Nine clinicopathological parameters were studied to correlate the molecular and clinical parameters. Additionally, we investigated for micrometastases in blood in 18 of these patients and in 10 of the controls samples.

RESULTS

All samples had detectable quantities of beta-actin RNA. In the controls, one case (4%) was positive for CEA and five (20%) for CK19 RNA; of the 53 patients, 17 cases (32%) were positive for CEA and 39 (73.6%) for CK19 RNA. This was statistically significant (p=0.000001). Advanced stages (p=0.03) and soluble CEA status (p=0.03) were associated with the presence of CEA, CK19, or both RNAs in plasma. Lymph node metastases (p=0.06) and vascular invasion (p=0.07) were almost significant. On the basis of these results, we examined the possible presence of micrometastases in blood in several of these patients. The presence of plasma tumour RNA was found to be associated with circulating tumour cells in blood (p=0.04).

CONCLUSIONS

Epithelial tumour RNA is detectable in plasma from colon cancer patients. This molecular event is associated with advanced stages and circulating tumour cells. Our results could offer new approaches in the diagnosis and monitoring of colon cancer.

Detection of epithelial messenger RNA in the plasma of breast cancer patients is associated with poor prognosis tumor characteristics

PURPOSE

Free plasma RNA has been scarcely studied in patients with cancer. Here we examine the presence of RNA from epithelial tumors in plasma from a series of breast cancer patients and its correlation with tumor characteristics and circulating tumor cells.

EXPERIMENTAL DESIGN

beta-actin mRNA was analyzed to check the viability of plasma RNA in samples from 45 patients with breast cancer and 25 controls. Nested primers were used to detect the presence of cytokeratin 19 (CK19) and Mammaglobin in the same samples. Eleven clinicopathological parameters were studied and correlated with molecular parameters. Additionally, we looked for circulating tumor cells in 16 of these patients and in 10 of the controls.

RESULTS

All samples showed detectable quantities of beta-actin RNA. In controls, 3 cases (12%) were positive for Mammaglobin, and 5 (20%) were positive for CK19 RNA; of the 45 patients, 27 cases (60%) were positive for Mammaglobin, and 22 (49%) were positive for CK19. These differences were statistically significant (P = 0.001). Tumor size (P = 0.01) and proliferative index (P = 0.02) were associated with the presence of Mammaglobin, CK19, or both RNAs in plasma. Pathological stage (P = 0.06) was close to significance. Although a statistical relationship was not demonstrated, 9 of the 10 patients with circulating tumor cells showed epithelial mRNAs in plasma.

CONCLUSIONS

We conclude that epithelial tumor RNA is detectable in plasma from breast cancer patients and that this finding is associated with a probable poor prognosis and circulating tumor cells.

Genes in drug abuse

Because of the genome projects it will be possible to identify the changes in gene expression that are associated with drug abuse. The ultimate goal will be to determine the role and significance of the gene products. To date about 100 genes have been found with altered expression after administration of drugs. The development of new technologies such as microarrays will greatly facilitate finding such changes in expression. The rate at which levels of some gene products change is compatible with the time course of development of dependence in animals, but we must be able to establish a cause-effect relationship between genes and drug abuse, which this will be difficult. The product of the novel cocaine and amphetamine regulated transcript (CART) gene is a useful example where a gene product has been associated with drug abuse. CART was identified as an mRNA that changed in response to psychostimulant drug administration and injection of CART peptides into the ventral tegmental area produces psychostimulant-like effects. Definitive evidence, if obtainable, that specific genes are responsible for vulnerability to drug abuse could have dramatic effects on public health policy.

Wild type p73 overexpression and high-grade malignancy in breast cancer

The overexpression of wild type p73 is the most frequent alteration of p73 in malignancies. We investigated, in 70 breast carcinomas, p73 mRNA expression and its relationship to p53 mutations, determined by an immunohistochemical method, and loss heterozygosity (LOH) status of the 1p36 region, together with its possible implication in the pathogenesis of breast carcinomas. LOH, amplifying DNA by PCR using 5 markers, of 1p36 region (one intragenic to p73 gene) was found in 17% of cases but no significant correlation was observed with p73 overexpression. p53 positive immunostaining was present in 33% of breast carcinomas, and these exhibited a statistically significant relation with p73 overexpressed tumors. Overexpression of p73 mRNA was observed in 19 tumors (27%). The analysis of cases with p73 overexpression and cases with normal mRNA expression, in terms of age and pathologic characteristics of the tumors showed a significant association of p73 overexpression and tumors with lymph node metastases, vascular invasion and higher pathologic stage. These results suggest that p73 overexpression is a molecular alteration that could be implicated in the tumorigenesis of breast carcinomas and, eventually, in a poor clinical behavior.

Spur cell anaemia and acute haemolysis in patients with hyperreactive malarious splenomegaly. Experience in an isolated Yanomamo population of Venezuela

A prospective study, aimed to investigate the aetiology of an unusual clustering of cases of severe acute haemolytic anaemia affecting a high percentage of the adult population, was carried out in two isolated Yanomamo communities of the Upper Orinoco basin in Venezuela. Twenty-six patients with active or recent episodes of severe haemolysis were evaluated. All of them exhibited massive liver and spleen enlargement and fulfilled the diagnostic criteria of the hyperreactive malarious splenomegaly (HMS) syndrome. In four cases with advanced non-alcohol-related chronic liver disease, hypersplenism, severe haemolytic anaemia and acanthocytosis, the characteristic clinical and laboratory findings of spur cell anaemia were documented. Chronic infection by the HBV and HCV was present in three of them. However, in most of the 22 additional HMS cases, the acute haemolytic condition appeared associated with the occurrence of a cold agglutinin-mediated autoimmune response. The clustering of a significant number of cases of severe acute haemolysis in HMS patients from this small isolated aboriginal community is most unusual, and represents a serious complicating factor for a population already beleaguered by a high prevalence of malaria due to multiresistant strains of Plasmodium falciparum. Moreover, the coexistence of HMS and severe chronic HBV or HCV infection may further aggravate the course of the haemolytic disorder, because of the occurrence of spur cell anaemia.

DNA damage after chemotherapy correlates with tumor response and survival in small cell lung cancer patients

To explore the induction of chemotherapy (CT) DNA damage and its correlation with tumor response and patient survival, we undertook the present study in 20 small cell lung cancer (SCLC) patients. All patients underwent the same treatment based on CT courses of carboplatin and etoposide. Blood samples were taken before and immediately after CT and every 12 weeks during follow-up. Nuclear DNA damage was determined through the variations in three mitochondrial pseudogene mutations in DNA of peripheral blood mononuclear cells. They were detected by mutation-specific PCR and assessed by a semiquantitative method. The relative level of mutation rose after chemotherapy in all cases. Among the 11 patients (55%) with higher relative levels of mutations, 9 (82%) of them achieved a complete response. In contrast, of the 9 patients (45%) with lower relative levels of mutations, only 2 (18%) achieved a complete response, displaying a statistically significant difference (P=0.02). The overall survival for patients with marked genomic damage was 18 months (range 10-24), and for patients with low degree of DNA damage, it was 12 months (range 5-15) (P=0.002). Genomic damage detected after chemotherapy treatment correlates positively with tumor response and patient survival.

Clinicopathological characteristics of breast carcinomas with allelic loss in the p73 region

p73, a new member of the p53 family, has been mapped to chromosome 1p 36, a region where loss of heterozygosity (LOH) is frequently observed in primary human tumors. Allelic loss studies involving the 1p arm in breast carcinomas offer rates ranging from 13% to 75%, depending on the genetic interval being studied. We investigated LOH in an intragenic microsatellite marker, and those centromerically flanking the p73 gene, at 1p 36, and their correlations with patient age and 10 pathologic parameters in a series of 193 breast carcinomas. The LOH analysis was performed by amplifying DNA by PCR, using the five markers of the 1p 36 region (p73P1, D1S2694, D1S214, D1S2666 and D1S450). LOH was found in at least one of these markers in 27% of tumors. When we established the comparison between tumors with and without LOH and the distribution of the 10 pathologic parameters considered, we observed statistically significant differences in association with higher histologic grade (p = 0.02), more advanced pathological stage (p = 0.02), peritumoral vessel involvement (p = 0.04) and poorly differentiated carcinomas (p = 0.01), as well as in tumors that concomitantly exhibited lymph node metastases, peritumoral vessel involvement and absence of steroid receptors (p = 0.02). These data suggest that LOH in the p73 region could be pathogenically related to breast cancer and possibly to a poor tumor prognosis.

Microsatellite alterations and TP53 mutations in plasma DNA of small-cell lung cancer patients: follow-up study and prognostic significance

BACKGROUND

Small-cell lung cancer (SCLC), one of the major types of lung cancer, is associated with many different somatic molecular genetic changes. These alterations, observed in tumor DNA, have also been identified in the plasma DNA of patients. We undertook the present study to make a prospective investigation into the correlation between abnormal plasma DNA and patient survival.

PATIENTS AND METHODS

Thirty-five patients with SCLC were selected after histological diagnosis. Polymorphic markers (ACTBP2, UT762 and AR) were chosen for their reported high rate of alterations in SCLC and analyzed in tumor tissue, normal blood cells and plasma DNA. Furthermore, we looked for mutations of the TP53 gene in tumor and plasma DNA.

RESULTS

In 25 patients (71%) at least one molecular change precisely matching that of the primary tumor was detected in the plasma DNA. No difference in survival was observed between patients with aberrant plasma DNA and patients without plasma DNA alterations. However, patients with microsatellite modifications and TP53 mutations concomitantly, showed a significant difference (P = 0.02) in survival compared with patients bearing only one of these molecular changes. In 15 cases it was possible to find a correlation either between tumor response and disappearance of abnormal plasma DNA, or tumor progression and persistence of plasma DNA alterations.

CONCLUSIONS

Free plasma DNA with molecular alterations is present to a high degree in plasma DNA of SCLC patients and may have a role as a prognostic factor.

Promoter hypermethylation and BRCA1 inactivation in sporadic breast and ovarian tumors

BACKGROUND

Inherited mutations in the BRCA1 gene may be responsible for almost half of inherited breast carcinomas. However, somatic (acquired) mutations in BRCA1 have not been reported, despite frequent loss of heterozygosity (LOH or loss of one copy of the gene) at the BRCA1 locus and loss of BRCA1 protein in tumors. To address whether BRCA1 may be inactivated by pathways other than mutations in sporadic tumors, we analyzed the role of hypermethylation of the gene's promoter region.

METHODS

Methylation patterns in the BRCA1 promoter were assessed in breast cancer cell lines, xenografts, and 215 primary breast and ovarian carcinomas by methylation-specific polymerase chain reaction (PCR). BRCA1 RNA expression was determined in cell lines and seven xenografts by reverse transcription-PCR. P values are two-sided.

RESULTS

The BRCA1 promoter was found to be unmethylated in all normal tissues and cancer cell lines tested. However, BRCA1 promoter hypermethylation was present in two breast cancer xenografts, both of which had loss of the BRCA1 transcript. BRCA1 promoter hypermethylation was present in 11 (13%) of 84 unselected primary breast carcinomas. BRCA1 methylation was strikingly associated with the medullary (67% methylated; P =.0002 versus ductal) and mucinous (55% methylated; P =.0033 versus ductal) subtypes, which are overrepresented in BRCA1 families. In a second series of 66 ductal breast tumors informative for LOH, nine (20%) of 45 tumors with LOH had BRCA1 hypermethylation, while one (5%) of 21 without LOH was methylated (P =.15). In ovarian neoplasms, BRCA1 methylation was found only in tumors with LOH, four (31%) of 13 versus none of 18 without LOH (P =.02). The BRCA1 promoter was unmethylated in other tumor types.

CONCLUSION

Silencing of the BRCA1 gene by promoter hypermethylation occurs in primary breast and ovarian carcinomas, especially in the presence of LOH and in specific histopathologic subgroups. These findings support a role for this tumor suppressor gene in sporadic breast and ovarian tumorigenesis.

Absence of point mutations at codon 17 of the mdm2 gene (serine 17) in human primary tumors

Mdm2 is a phosphoprotein that interacts with protein p53, inhibiting its activity. A serine located in position 17 of Mdm2, has been implicated in its phosphorylation process. We hypothesize that point mutations at serine 17 could block its phosphorylation and thereby increase the p53-Mdm2 interaction. This mechanism could increase the p53 degradation and cause a loss of the protective effect of p53 against tumorigenesis. This hypothesis was based on recent studies in vitro, demonstrating that when serine 17 is mutated, the DNA-dependent protein kinase, activated by genomic damage, is unable to phosphorylate it. Thus, we investigated whether structural point mutations at exon 3 of the Mdm2 gene, affecting codon 17, were present in 162 human primary tumors, 70 breast carcinomas, 14 bladder tumors, 18 colon adenocarcinomas and 60 testicular tumors. Direct sequencing of a fragment (204 bp) of exon 3 of the Mdm2 gene that contains the codon 17 showed no mutations at this position, independently of the presence or absence of p53 gene mutations in the same tumors. These results do not support the hypothesis that mutations in the Mdm2 gene at this level are involved in the tumorigenic process of human cancers.

Mutational status of K-ras and TP53 genes in primary sarcomas of the heart

We investigated three patients with cardiac angiosarcomas and two with cardiac rhabdomyosarcomas, all for mutations at exons 5, 6, 7 and 8 of the p53 gene and at exon 1 of K-ras. No point mutations were observed in the p53 gene in any of the five cases; however, at exon 1 of K-ras, three patients (60%) presented the same mutation at the first base of codon 13 (G to A transition). Interestingly, this mutation was detected in both rhabdomyosarcoma and angiosarcoma histologic sarcoma types.

Detection of loss of heterozygosity at RAD51, RAD52, RAD54 and BRCA1 and BRCA2 loci in breast cancer: pathological correlations

Loss of heterozygosity (LOH) in loci of the 15q15.1, 12p13, 1p32, 17q21 and 13q12-13 regions may collaborate in the inactivation of RAD51, RAD52, RAD54, BRCA1, BRCA2 and possibly other genes implicated in the repair of double-stranded DNA and in DNA recombination. We investigate allelic losses in microsatellites of the RAD51, RAD52, RAD54, BRCA1 and BRCA2 regions, and their correlations with nine pathologic parameters in 127 breast carcinomas. The LOH analysis was performed by amplifying DNA by PCR, using 15 markers of the 15q15.1, 12p13.3, 1p32, 17q21 and 13q12-13 regions. LOH was found in the RAD51 region in 32% of tumours, in the RAD52 region in 16%, in RAD54 in 20% and in the BRCA1 and BRCA2 regions in 49% and 44% respectively. Significant correlations between one or more regions with concomitant LOH and pathologic parameters were observed with respect to age (P = 0.008), oestrogen receptor content (P = 0.03), progesterone receptors (P = 0.003), higher grade (P = 0.001), more advanced stage (P = 0.004) and peritumoural vessel involvement (P < 0.0001). The number of cases in which LOH was observed simultaneously in two or more regions was always higher than expected on the basis of their statistical probability, and curiously, the three patients with LOH at five regions concomitantly were under the age of 30 years. These results suggest that LOH at these regions could be related to breast cancer, and probably to a poor tumour prognosis.

Human herpesvirus 6B genome sequence: coding content and comparison with human herpesvirus 6A

Human herpesvirus 6 variants A and B (HHV-6A and HHV-6B) are closely related viruses that can be readily distinguished by comparison of restriction endonuclease profiles and nucleotide sequences. The viruses are similar with respect to genomic and genetic organization, and their genomes cross-hybridize extensively, but they differ in biological and epidemiologic features. Differences include infectivity of T-cell lines, patterns of reactivity with monoclonal antibodies, and disease associations. Here we report the complete genome sequence of HHV-6B strain Z29 [HHV-6B(Z29)], describe its genetic content, and present an analysis of the relationships between HHV-6A and HHV-6B. As sequenced, the HHV-6B(Z29) genome is 162,114 bp long and is composed of a 144,528-bp unique segment (U) bracketed by 8,793-bp direct repeats (DR). The genomic sequence allows prediction of a total of 119 unique open reading frames (ORFs), 9 of which are present only in HHV-6B. Splicing is predicted in 11 genes, resulting in the 119 ORFs composing 97 unique genes. The overall nucleotide sequence identity between HHV-6A and HHV-6B is 90%. The most divergent regions are DR and the right end of U, spanning ORFs U86 to U100. These regions have 85 and 72% nucleotide sequence identity, respectively. The amino acid sequences of 13 of the 17 ORFs at the right end of U differ by more than 10%, with the notable exception of U94, the adeno-associated virus type 2 rep homolog, which differs by only 2.4%. This region also includes putative cis-acting sequences that are likely to be involved in transcriptional regulation of the major immediate-early locus. The catalog of variant-specific genetic differences resulting from our comparison of the genome sequences adds support to previous data indicating that HHV-6A and HHV-6B are distinct herpesvirus species.

Allelic loss of the PTEN region (10q23) in breast carcinomas of poor pathophenotype

Loss of heterozygosity (LOH) in loci of the 10q23 region that harbor the PTEN gene and mutations in the sequence of this gene have been found in several primary human tumors including breast carcinomas, suggesting that this gene could be implicated in their pathogenesis. We investigated allelic losses in microsatellites of the 10q23 region, and their correlations with nine pathologic parameters in 105 breast carcinomas. The LOH analysis was performed by amplifying DNA by PCR, using five markers of the 10q23 region (D10S1687, D10S541, D10S2491, D10S583 and D10S571). LOH in at least one marker of the PTEN region was found in 29.5% of tumors. The statistical comparison between carcinomas with and without LOH in terms of the pathologic parameters showed significant differences in age (p = 0.03), lymph node metastases (p = 0.02), and higher histological grade (p = 0.02); a trend toward significance was found for progesterone receptors (p = 0.05). LOH in an individual marker and statistically significant relationships to tumor characteristics were observed at locus D10S541 for lymph node metastases (p = 0.04), at D10S2491 (intragenic to the PTEN gene) for lymph node metastases (p = 0.02), and at D10S583 for progesterone receptors (p = 0.01) and for high grade (p = 0.03). These results suggest the PTEN gene, or other genes of the 10q23 region, could be functionally related to breast cancer, probably influencing the development of histological features associated with poor prognosis.

Presence of tumor DNA in plasma of breast cancer patients: clinicopathological correlations

Using different molecular techniques, DNA has been detected in the plasma of cancer patients with various types of tumors. We undertook the present study to investigate the presence of plasma DNA, before mastectomy, in patients with breast cancer at diagnosis and to analyze the clinicopathological spectrum of this subgroup of patients with respect to patients without DNA with tumor characteristics. We studied 62 patients with breast cancer, who were selected sequentially after mastectomy and diagnosis of breast carcinomas. Genomic DNA extracted from tumor and normal tissues, normal blood cells, and plasma was used for molecular studies. Alterations in polymorphic markers selected because they had been found to show a high rate of alterations in breast cancer in previous studies (D17S855, D17S654, D16S421, TH2, D10S197, and D9S161), as well as mutations in the p53 gene and aberrant methylation at the first exon of p16INK4a, were used to identify and characterize tumor and plasma DNA. Thirteen clinicopathological parameters were analyzed in each patient. We identified 56 cases (90%) with at least one molecular event in tumor DNA, and 41 cases (66%) with a similar alteration in plasma DNA. Comparison of the clinicopathological parameters between patients with and without plasma DNA revealed significant differences in the axillary involvement, rate of invasive ductal carcinoma, high proliferative index, and the parameter comprised of lymph node metastases, histological grade II, and peritumoral vessel involvement. A high proportion of breast cancer patients exhibited plasma DNA at diagnosis similar to tumor DNA, and its presence correlated significantly with pathological parameters associated with a poor prognosis.

Aberrant DNA methylation of the p16INK4a gene in plasma DNA of breast cancer patients

Hypermethylation of exon 1 of p16INK4a was examined in tumour and plasma DNA of a series of breast cancer patients. De novo methylation was observed in the tumours of eight patients (23%), and in plasma DNA in five (14%) of these eight patients. Our data show that de novo methylation of exon 1 of p16INK4a can be demonstrated in plasma DNA of breast cancer patients, a fact that provides additional evidence of the tumour-related origin of free plasma DNA in cancer patients.

Abnormal frequencies of alleles in polymorphic markers of the 17q21 region is associated with breast cancer

This study was carried out to evaluate the frequencies of alleles of four polymorphic markers in the 17q21 region in breast cancer patients, and their relation to seven pathological parameters. One hundred and sixty-four patients with breast cancer and 102 controls were analyzed. D17S856, D17S855, D17S1323 and D17S1327 polymorphic markers were studied, and used to investigate loss of heterozygosity in this region. The frequencies of alleles at marker D17S856 differed significantly in breast cancer patients and controls, and were related to histologic features considered to indicate a poor prognosis. When present, the pathophenotype of tumors associated with LOH in the 17q21 region is modified.

TP53 gene mutations in plasma DNA of cancer patients

Using different molecular techniques, DNA has been shown to be present in plasma of patients with several types of tumors. Mutations of TP53 are the most common genetic changes in human cancers. We investigated the presence of TP53 gene mutations in plasma DNA of breast and small cell lung cancer patients. Tumor and plasma DNA of 25 patients were studied by PCR-SSCP and direct sequencing, through exons 5, 6, 7, and 8, of TP53. Six cases of mutations in tumor DNA were observed that, in 3 cases (50%), were also identified in plasma of the same patients. Mutations of the TP53 gene are seen in plasma DNA of cancer patients, and may prove to be a useful new tool in the management of these patients.