The histone mark H3K36me2 recruits DNMT3A and shapes the intergenic DNA methylation landscape

Enzymes catalyzing CpG methylation in DNA, including DNMT1 and DNMT3A/B, are indispensable for mammalian tissue development and homeostasis^1–4. They are also implicated in human developmental disorders and cancers^5–8, supporting a critical role of DNA methylation during cell fate specification and maintenance. Recent studies suggest that histone post-translational modifications (PTMs) are involved in specifying patterns of DNMT localization and DNA methylation at promoters and actively transcribed gene bodies^9–11. However, mechanisms governing the establishment and maintenance of intergenic DNA methylation remain poorly understood. Germline mutations in DNMT3A define Tatton-Brown-Rahman syndrome (TBRS), a childhood overgrowth disorder that shares clinical features with Sotos syndrome caused by haploinsufficiency of NSD1, a histone methyltransferase catalyzing di-methylation on H3K36 (H3K36me2)^8,12,13, pointing to a potential mechanistic link between the two diseases. Here we report that NSD1-mediated H3K36me2 is required for recruitment of DNMT3A and maintenance of DNA methylation at intergenic regions. Genome-wide analysis shows that binding and activity of DNMT3A co-localize with H3K36me2 at non-coding regions of euchromatin. Genetic ablation of NSD1 and its paralogue NSD2 in cells redistributes DNMT3A to H3K36me3-marked gene bodies and reduces intergenic DNA methylation. NSD1 mutant tumors and Sotos patient samples are also associated with intergenic DNA hypomethylation. Accordingly, the PWWP-domain of DNMT3A shows dual recognition of H3K36me2/3 in vitro with a higher binding affinity towards H3K36me2, which is abrogated by TBRS-derived missense mutations. Taken together, our study uncovers a trans-chromatin regulatory pathway that connects aberrant intergenic CpG methylation to human neoplastic and developmental overgrowth.

Short chain fatty acid rectal irrigation for left-sided ulcerative colitis: a randomised, placebo controlled trial

BACKGROUND

Short chain fatty acid (SCFA) deficiency is associated with colitis in animals and humans, and the mucosal metabolism of these compounds is decreased in ulcerative colitis.

AIMS

To assess the efficacy of topical SCFA treatment in ulcerative colitis.

PATIENTS AND METHODS

103 patients with distal ulcerative colitis were entered into a six week, double-blind, placebo controlled trial of rectal SCFA twice daily; patients who were unchanged on placebo were offered SCFA in an open-label extension trial.

RESULTS

Of the 91 patients completing the trial, more patients in the SCFA treated than in the placebo treated group improved (33% v 20%, p = 0.14, NS). Those on SCFA also had larger, but statistically non-significant, reductions in every component of their clinical and histological activity scores. In patients with a relatively short current episode of colitis (< 6 months, n = 42), more responded to SCFA than to placebo (48% v 18%, p = 0.03). These patients also had larger, but statistically non-significant, decreases in their clinical activity index (p = 0.08 v placebo). Every patient who improved used at least five of six of the prescribed rectal SCFA irrigations, whereas only 37% who did not improve were as compliant. In the open-label extension trial, 65% improved on SCFA; these patients also had significant reductions (p < 0.02) in their clinical and histological activity scores.

CONCLUSIONS

Although SCFA enemas were not of therapeutic value in this controlled trial, the results suggest efficacy in subsets of patients with distal ulcerative colitis including those with short active episodes. Prolonged contact with rectal mucosa seems to be necessary for therapeutic benefit.

ART (protein product of agouti-related transcript) as an antagonist of MC-3 and MC-4 receptors

The mRNA encoding an agouti related protein (ART) of unknown biochemical function was previously reported to be up-regulated in the hypothalamus of two genetically obese mouse strains. We have expressed human ART as a secreted protein in COS-7 cells, and show that recombinant ART is functionally active in inhibiting the binding of a radiolabeled alpha-melanocyte stimulating hormone (alpha-MSH) analog to the human melanocortin-3 (MC-3) and melanocortin-4 (MC-4) receptors, while it is not a potent inhibitor of the human melanocortin-5 (MC-5) receptor. ART is an antagonist of the human MC-3 and MC-4 receptors as determined in functional assay. ART appears to be approximately 100-fold more potent than agouti with reference to the MC-3R and MC-4R binding affinity. These data suggest that ART may be a physiological regulator of feeding behavior.

Adjunctive raloxifene treatment improves attention and memory in men and women with schizophrenia

There is increasing clinical and molecular evidence for the role of hormones and specifically estrogen and its receptor in schizophrenia. A selective estrogen receptor modulator, raloxifene, stimulates estrogen-like activity in brain and can improve cognition in older adults. The present study tested the extent to which adjunctive raloxifene treatment improved cognition and reduced symptoms in young to middle-age men and women with schizophrenia. Ninety-eight patients with a diagnosis of schizophrenia or schizoaffective disorder were recruited into a dual-site, thirteen-week, randomized, double-blind, placebo-controlled, crossover trial of adjunctive raloxifene treatment in addition to their usual antipsychotic medications. Symptom severity and cognition in the domains of working memory, attention/processing speed, language and verbal memory were assessed at baseline, 6 and 13 weeks. Analyses of the initial 6-week phase of the study using a parallel groups design (with 39 patients receiving placebo and 40 receiving raloxifene) revealed that participants receiving adjunctive raloxifene treatment showed significant improvement relative to placebo in memory and attention/processing speed. There was no reduction in symptom severity with treatment compared with placebo. There were significant carryover effects, suggesting some cognitive benefits are sustained even after raloxifene withdrawal. Analysis of the 13-week crossover data revealed significant improvement with raloxifene only in attention/processing speed. This is the first study to show that daily, oral adjunctive raloxifene treatment at 120 mg per day has beneficial effects on attention/processing speed and memory for both men and women with schizophrenia. Thus, raloxifene may be useful as an adjunctive treatment for cognitive deficits associated with schizophrenia.

Anatomy of arteriovenous crossings in branch retinal vein occlusion

We studied the photographic records of 292 eyes, including 103 eyes with branch retinal vein occlusion, 90 fellow eyes, and 99 control eyes without branch retinal vein occlusion. All arteriovenous crossings within three disk diameters of the optic disk, including the crossings at the sites of branch retinal vein occlusions, were studied. The relative positions of the crossing artery and vein could be determined at 1,939 crossings in all eyes. Crossings at which a vein crossed over an artery were a common finding (22.3% to 33.0% of crossings), but were rare at the crossings where branch retinal vein occlusions were found (2.4%). A greater proportion of arterial overcrossings was found in eyes with branch retinal vein occlusions (77.7%) compared to fellow eyes (70.6%) or control eyes (67.0%). Our data indicate that arterial overcrossings are at relatively higher risk of branch retinal vein occlusion than venous overcrossings, and that the risk of branch vein occlusion in an eye is proportional to the number of arterial overcrossings in the eye.

D-Amino acid scan of gamma-melanocyte-stimulating hormone: importance of Trp(8) on human MC3 receptor selectivity

In our search for potent and receptor-selective agonists and antagonists, we report here the results of D-amino acid substitution at each position of the short peptide gamma-melanocyte-stimulating hormone (gamma-MSH). The native gamma-MSH shows weak binding at all three receptors (i.e., the human MC3, MC4, and MC5) and a selectivity of 1-2 orders of magnitude at the MC3R over the MC4R and MC5R. Sequential replacement of each residue in the gamma-MSH sequence with the corresponding D-isomer results in analogues which mostly have weaker binding affinity than the native peptide, except for two analogues. For the DTrp(8) analogue, there is an increase in binding affinity by about 1 order of magnitude (IC(50) = 6 nM) at the MC3R compared with that of the natural molecule and an increase in selectivity for the MC3R by 2 orders of magnitude compared with the activity at the MC4R and MC5R. The DPhe(6) analogue is about 10-fold more potent (IC(50) = 8.8 nM) at the MC3R compared with the native peptide but lacks subtype selectivity. Measurement of the intracellular cAMP accumulation in human MC3R, MC4R, and MC5R revealed that the native peptide shows potent activity at the MC3R (EC(50) = 5.9 nM) and is about 50-100-fold selective at this receptor compared with the MC4R and MC5R. The DArg(10) (EC(50) = 35 nM) and DPhe(11) (EC(50) = 11 nM) analogues are selective for the MC3R by 1 and 2 orders of magnitude compared with the MC4R and MC5R, respectively. The DTrp(8) compound (EC(50) = 0.33 nM) shows about 300- and 250-fold increase in selectivity at the MC3R compared with the MC4R and MC5R, respectively. Finally, the DTyr(1) peptide is selective for the MC3R (EC(50) = 12 nM) by 40-200-fold compared with the MC4R and MC5R. In general, the trend is that D-amino acid substitutions of the aromatic residues 1, 6, 8, and 11 and the basic residue Arg(10), but not Arg(7), result in an increase in MC3R selectivity over the MC4R and MC5R and only agonist activity is observed. Thus, the key residues of gamma-MSH identified in this study include the aromatic residues 1, 6, 8, and 11 and the basic residue Arg(10) (but not Arg(7)), as important for MC3 selectivity over the MC4 and MC5 subtypes. Further, the study reveals the extreme importance of DTrp at position 8 in imparting potency and selectivity since this is the most selective analogue for the human MC3R reported thus far.

Improvement in visual acuity in chronic aphakic and pseudophakic cystoid macular edema after treatment with topical 0.5% ketorolac tromethamine

Ketorolac tromethamine 0.5% ophthalmic solution treatment was compared to placebo treatment in 120 patients with chronic aphakic or pseudophakic cystoid macular edema (six-month or more duration of distance visual acuity of 20/40 or less and angiographic evidence of cystoid changes) during a four- to five-month double-masked, multicenter study in which patients were randomly assigned. A statistically significant improvement in distance visual acuity (two lines or more) was observed in the ketorolac-treated group as compared to the placebo-treated group after 30 days (P = .038), 60 days (P = .017), and 90 days (P = .008) of treatment. This improvement in visual acuity remained statistically significant one month after cessation of treatment (P = .001). Nine ketorolac-treated patients and two placebo-treated patients demonstrated a decrease in visual acuity one month after treatment was discontinued. Seven of the nine ketorolac-treated patients experienced an improvement in visual acuity after retreatment as compared to none of the placebo-treated patients. This study offers evidence for a more optimistic outlook in the medical treatment of chronic aphakic and pseudophakic cystoid macular edema.

Pneumonia in pediatric outpatients: cause and clinical manifestations

The cause and clinical manifestations of pneumonia were studied in 98 pediatric outpatients. A viral diagnosis was established in 38 (39%) of the 98 patients, and a bacterial diagnosis in 19 (19%). Ten (53%) of the 19 patients with bacterial pneumonia had a concurrent viral infection. No clinical, laboratory, or radiographic findings that would reliably differentiate viral from bacterial infection were identified. This study suggests that bacterial pneumonia is more common in pediatric outpatients than previously reported, and that the clinical, laboratory, and radiographic findings in patients with bacterial infection may be indistinguishable from findings in patients with viral infection.

Guanylyl cyclase C messenger RNA is a biomarker for recurrent stage II colorectal cancer

BACKGROUND

Patients with stage II colorectal cancer and no histologic evidence of lymph node invasion develop recurrent disease, presumably because of undetected micrometastases. Guanylyl cyclase C is expressed by intestinal and colorectal cancer cells but not by extraintestinal tissues or tumors.

OBJECTIVE

To examine the expression of guanylyl cyclase C messenger RNA (mRNA) in lymph nodes of patients with node-negative colorectal cancer who did and did not have recurrent disease.

DESIGN

Case-control study.

SETTING

Tertiary care academic medical center.

PATIENTS

Paraffin-embedded lymph nodes were obtained from 21 patients with histologically confirmed node-negative colorectal cancer who had undergone resection. Controls included 11 patients without disease recurrence 6 or more years after resection, and case-patients included 10 patients whose disease recurred up to 3 years after resection.

MEASUREMENTS

Sections of paraffin-embedded lymph nodes were obtained from each patient and were pooled, and their RNA was analyzed by reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Guanylyl cyclase C mRNA was expressed in lymph nodes from all patients with recurrent disease but not in those from patients without recurrent disease (P = 0.004). Nested RT-PCR that used primers for carcinoembryonic antigen, a marker for colorectal cancer, identified carcinoembryonic antigen mRNA in lymph nodes from only 1 of 10 patients with recurrent disease and those from 0 of 11 patients without recurrent disease. The odds ratio for death associated with expression of guanylyl cyclase C mRNA in regional lymph nodes was 15.0 (95% CI, 1.1 to 756.7).

CONCLUSIONS

Expression of guanylyl cyclase C mRNA in lymph nodes is associated with recurrence of colorectal cancer in patients with stage II disease. Analysis of guanylyl cyclase mRNA expression by RT-PCR may be useful for colorectal cancer staging.

Human melanoma metastasis in NSG mice correlates with clinical outcome in patients

Studies of human cancer metastasis have been limited by a lack of experimental assays in which cancer cells from patients metastasize in vivo in a way that correlates with clinical outcome. This makes it impossible to study intrinsic differences in the metastatic properties of cancers from different patients. We recently developed an assay in which human melanomas readily engraft in nonobese diabetic/severe combined immunodeficient interleukin-2 receptor-γ chain null (NSG) mice. We show that melanomas from 25 patients exhibited reproducible differences in the rate of spontaneous metastasis after transplantation into NSG mice and that these differences correlated with clinical outcome in the patients. Stage IIIB/C melanomas that formed distant metastases within 22 months in patients also formed tumors that metastasized widely in NSG mice, whereas stage IIIB/C melanomas that did not form distant metastases within 22 to 50 months in patients metastasized more slowly in NSG mice. These differences in the efficiency of metastasis correlated with the presence of circulating melanoma cells in the blood of NSG mice, suggesting that the rate of entry into the blood is one factor that limits the rate of metastasis. The study of NSG mice can therefore yield information about the metastasis of human melanomas in vivo, in this case revealing intrinsic differences among stage III melanomas in their ability to circulate/survive in the blood and to metastasize.

Two competing mechanisms of DNMT3A recruitment regulate the dynamics of de novo DNA methylation at PRC1-targeted CpG islands

Precise deposition of CpG methylation is critical for mammalian development and tissue homeostasis and is often dysregulated in human diseases. The localization of de novo DNA methyltransferase DNMT3A is facilitated by its PWWP domain recognizing histone H3 lysine 36 (H3K36) methylation1,2 and is normally depleted at CpG islands (CGIs)3. However, methylation of CGIs regulated by Polycomb repressive complexes (PRCs) has also been observed4-8. Here, we report that DNMT3A PWWP domain mutations identified in paragangliomas9 and microcephalic dwarfism10 promote aberrant localization of DNMT3A to CGIs in a PRC1-dependent manner. DNMT3A PWWP mutants accumulate at regions containing PRC1-mediated formation of monoubiquitylated histone H2A lysine 119 (H2AK119ub), irrespective of the amounts of PRC2-catalyzed formation of trimethylated histone H3 lysine 27 (H3K27me3). DNMT3A interacts with H2AK119ub-modified nucleosomes through a putative amino-terminal ubiquitin-dependent recruitment region, providing an alternative form of DNMT3A genomic targeting that is augmented by the loss of PWWP reader function. Ablation of PRC1 abrogates localization of DNMT3A PWWP mutants to CGIs and prevents aberrant DNA hypermethylation. Our study implies that a balance between DNMT3A recruitment by distinct reader domains guides de novo CpG methylation and may underlie the abnormal DNA methylation landscapes observed in select human cancer subtypes and developmental disorders.

Use of guanylyl cyclase C for detecting micrometastases in lymph nodes of patients with colon cancer

INTRODUCTION

Guanylyl cyclase C appears to be expressed only in colorectal cancer cells in extraintestinal tissues. Thus, guanylyl cyclase C may be useful as a marker to detect colorectal cancer micrometastases not detectable by histopathology in lymph nodes of patients.

METHODS

Twelve patients with colon adenocarcinoma, Dukes Stages A through C2, and one patient with a tubulovillous adenoma were included in this study. Forty-two lymph nodes were collected from fresh surgical specimens, and each was examined by histopathology and reverse transcription followed by polymerase chain reaction using guanylyl cyclase C-specific primers. Histopathology identified colon cancer cells in 6 of 16 lymph nodes from five Dukes Stage C patients but not in lymph nodes from the patient with a tubulovillous adenoma, the Dukes Stage A patient, or six Dukes Stage B patients. Reverse transcription followed by polymerase chain reaction using guanylyl cyclase C-specific primers was performed on all 42 lymph nodes.

RESULTS

Guanylyl cyclase C messenger RNA was not detected by reverse transcription followed by polymerase chain reaction in lymph nodes from the patient with the tubulovillous adenoma or the patient with Dukes Stage A colon carcinoma. Seven lymph nodes from Dukes Stage C patients revealed guanylyl cyclase C messenger RNA including six lymph nodes containing histopathologically confirmed metastases. Of significance, guanylyl cyclase C messenger RNA was detected in 6 of 21 lymph nodes from Dukes Stage B patients. Indeed, clinical staging of two patients could be upgraded from B to C using reverse transcription followed by polymerase chain reaction and guanylyl cyclase C-specific primers.

CONCLUSION

Reverse transcription followed by polymerase chain reaction using guanylyl cyclase C-specific primers might be useful to more accurately assess micrometastases in lymph nodes of colorectal cancer patients undergoing disease staging.

Factors affecting methane production in humans. Gastrointestinal diseases and alterations of colonic flora

Breath methane was studied in 394 subjects. Among 152 controls, 50.0% produced methane--42.1% of males and 57.9% of females. One hundred sixteen patients with gastrointestinal diseases were studied. Among 32 with Crohn's disease, only 2 (6.1%) produced methane, as well as 16 of 51 ulcerative colitis patients (31.4%) and 11 of 32 patients with the irritable bowel syndrome (34.4%). Breath methane is thus unusual in Crohn's disease. After bowel cleansing for colonoscopy or surgery, 15 of 18 methane producers became nonproducers, whereas after antibiotic treatment, 24 of 30 producers sustained their methane-producing status. After gentamycin and cephazolin therapy, methane production was abolished in three of eight patients. Slight spontaneous variations in methane production were also noticed with two of 23 control subjects, becoming nonproducers on restudy after 10-25 months. Thus gastrointestinal diseases, bowel cleansing and, to a much lesser degree, antibiotic therapy, affect methane production.

Multicentre prospective cohort study of body mass index and postoperative complications following gastrointestinal surgery

BACKGROUND

There is currently conflicting evidence surrounding the effects of obesity on postoperative outcomes. Previous studies have found obesity to be associated with adverse events, but others have found no association. The aim of this study was to determine whether increasing body mass index (BMI) is an independent risk factor for development of major postoperative complications.

METHODS

This was a multicentre prospective cohort study across the UK and Republic of Ireland. Consecutive patients undergoing elective or emergency gastrointestinal surgery over a 4-month interval (October-December 2014) were eligible for inclusion. The primary outcome was the 30-day major complication rate (Clavien-Dindo grade III-V). BMI was grouped according to the World Health Organization classification. Multilevel logistic regression models were used to adjust for patient, operative and hospital-level effects, creating odds ratios (ORs) and 95 per cent confidence intervals (c.i.).

RESULTS

Of 7965 patients, 2545 (32·0 per cent) were of normal weight, 2673 (33·6 per cent) were overweight and 2747 (34·5 per cent) were obese. Overall, 4925 (61·8 per cent) underwent elective and 3038 (38·1 per cent) emergency operations. The 30-day major complication rate was 11·4 per cent (908 of 7965). In adjusted models, a significant interaction was found between BMI and diagnosis, with an association seen between BMI and major complications for patients with malignancy (overweight: OR 1·59, 95 per cent c.i. 1·12 to 2·29, P = 0·008; obese: OR 1·91, 1·31 to 2·83, P = 0·002; compared with normal weight) but not benign disease (overweight: OR 0·89, 0·71 to 1·12, P = 0·329; obese: OR 0·84, 0·66 to 1·06, P = 0·147).

CONCLUSION

Overweight and obese patients undergoing surgery for gastrointestinal malignancy are at increased risk of major postoperative complications compared with those of normal weight.

Prognostic factors in medulloblastoma, including DNA ploidy

PURPOSE

DNA ploidy status, completeness of surgical resection, use of chemotherapy, adequacy of radiation therapy, metastatic stage, sex, and age at diagnosis were evaluated as predictors of relapse in 58 patients with cerebellar medulloblastoma.

METHODS

Flow cytometry (FCM) and/or image analysis (IA) were used to characterize tumor DNA ploidy. Twelve tumors (21%) were found to be aneuploid, 11 (19%) tetraploid, and 35 (60%) diploid.

RESULTS

The most significant predictors of relapse in univariate analyses were the adequacy of radiation (> or = 50 Gy) (P = .02), metastatic staging (P = .05), completeness of resection (P = .085), and DNA ploidy status (diploid/tetraploid v aneuploid; P = .11). When the 52 patients who received > or = 50 Gy were included in a multivariate Cox model analysis, those with diploid/tetraploid tumors had fewer recurrences than those with aneuploid tumors (relative risk, 0.33; 95% confidence interval, 0.12 to 0.89; P = .03). Patients with complete resections (P = .07), or with stage M0 disease (P = .06) had fewer recurrences than other patients, but these factors were not independent predictors of outcome. DNA ploidy status was correlated with age; 10 of the 12 aneuploid tumors were found in children ages 3 to 10 years. Age, sex, and the use of chemotherapy were not prognostically significant in these analyses.

CONCLUSION

The adequacy of radiation dose and DNA ploidy were the most important prognostic factors in this series. Contrary to previous reports, when corrected for adequacy of treatment, DNA aneuploidy was associated with a poor outcome. By multivariate analyses, DNA ploidy was an independent variable, even when controlling for extent of surgical resection and metastatic stage.

Ash1l controls quiescence and self-renewal potential in hematopoietic stem cells

Rapidly cycling fetal and neonatal hematopoietic stem cells (HSCs) generate a pool of quiescent adult HSCs after establishing hematopoiesis in the bone marrow. We report an essential role for the trithorax group gene absent, small, or homeotic 1-like (Ash1l) at this developmental transition. Emergence and expansion of Ash1l-deficient fetal/neonatal HSCs were preserved; however, in young adult animals, HSCs were profoundly depleted. Ash1l-deficient adult HSCs had markedly decreased quiescence and reduced cyclin-dependent kinase inhibitor 1b/c (Cdkn1b/1c) expression and failed to establish long-term trilineage bone marrow hematopoiesis after transplantation to irradiated recipients. Wild-type HSCs could efficiently engraft when transferred to unirradiated, Ash1l-deficient recipients, indicating increased availability of functional HSC niches in these mice. Ash1l deficiency also decreased expression of multiple Hox genes in hematopoietic progenitors. Ash1l cooperated functionally with mixed-lineage leukemia 1 (Mll1), as combined loss of Ash1l and Mll1, but not isolated Ash1l or Mll1 deficiency, induced overt hematopoietic failure. Our results uncover a trithorax group gene network that controls quiescence, niche occupancy, and self-renewal potential in adult HSCs.

Vulvar Cancer

This article reviews the epidemiology, diagnosis, and management of vulvar preinvasive lesions, squamous cell carcinoma, and melanoma. There is an emphasis on sentinel lymph node dissection for early stage disease and advances in chemoradiation for late-stage disease. A brief review of vulvar Paget disease is also included.

Oncogenic Mechanisms of Histone H3 Mutations

Recurrent missense mutations in histone H3 were recently reported in pediatric gliomas and soft tissue tumors. Strikingly, these mutations only affected a minority of the total cellular H3 proteins and occurred at or near lysine residues at positions 27 and 36 on the amino-terminal tail of H3 that are subject to well-characterized posttranslational modifications. Here we review recent progress in elucidating the mechanisms by which these mutations perturb the chromatin landscape in cells through their effects on chromatin-modifying machinery, particularly through inhibition of specific histone lysine methyltransferases. One common feature of histone mutations is their ability to arrest cells in a primitive state refractory to differentiation induction, highlighting the importance of studying these mutations in their proper developmental context.

Breast cancer treatment in clinical practice compared to best evidence and practice guidelines

There is sparse evidence on community practice patterns in treating women with breast cancer. This study compared care of women with breast cancer with evidence from meta-analyses and US National Comprehensive Cancer Network (NCCN) clinical guidelines. Records of 4395 women with breast cancer were abstracted from practices of 19 surgeon oncologists in six specialty practices in the Philadelphia region during 1995–1999. Patients were followed through December 2001. Low-frequency data were obtained on all patients. All other data were from a random sample of 464 women, minimum of 50 patients per practice. Actual care provided was compared to NCCN guidelines and results of meta-analyses. Fewer than half the women received treatments reflecting meta-analysis results or NCCN guidelines, by disease stage/TNM status. Adherence to either standard varied from 0% for LCIS to 87% for stages IIA or IIB node positive. There are multiple interactive reasons for low adherence to guidelines or meta-analyses results, including insufficient health system supports to clinicians, inadequate organisation and delivery systems and ineffective continuing medical education. The paucity of written information from patient records on physician/patient interactions limits the understanding of treatment decisions.

Synthetic atrial natriuretic factor does not dilate resistance-sized arteries

The effects of synthetic atrial natriuretic factor and atriopeptin III on induced tone in resistance-sized arteries from the rat were examined in vitro. Cylindrical segments of small mesenteric or cerebral arteries were mounted on a microcannula and pressurized to a transmural pressure of 75 mm Hg. After equilibration, the level of tone in cerebral arteries was on the order of - 35 change in diameter; addition of atrial natriuretic factor or atriopeptin III in cumulative doses from 10(-10) to 10(-7) M did not produce any transient or sustained changes in diameter. Similarly, atrial natriuretic factor or atriopeptin III did not alter the contractile responses of cerebral vessels to serotonin or prostaglandin F2 alpha. Mesenteric arteries, which do not possess an intrinsic myogenic tone, were precontracted with potassium (30 mM), norepinephrine (10(-6) M), or prostaglandin F2 alpha (1.1 X 10(-5) M) and exposed to the synthetic natriuretic peptides, also without effect. Transmural electrical stimulation (0.3-msec pulses; 180 mA; 4/second) relaxed cerebral and contracted mesenteric arteries; preincubation in 10(-7) M atrial natriuretic factor or atriopeptin III did not alter subsequent responses. These observations suggest that the hypotensive action of atrial natriuretic factor cannot be attributed to direct vasodilation of splanchnic or cerebral resistance-sized arteries.

Secondary metabolism: regulation by phosphate and trace elements

Secondary metabolism and cellular differentiation occur within a range of concentrations of phosphate and, in specific taxonomic groups, of zinc, manganese, and/or iron that is much narrower than that permittee for primary metabolism. Possible molecular sites of action of the four elements are reviewed.

Metal-organic frameworks tailor the properties of aluminum nanocrystals

Metal-organic frameworks (MOFs) and metal nanoparticles are two classes of materials that have received considerable recent attention, each for controlling chemical reactivities, albeit in very different ways. Here, we report the growth of MOF shell layers surrounding aluminum nanocrystals (Al NCs), an Earth-abundant metal with energetic, plasmonic, and photocatalytic properties. The MOF shell growth proceeds by means of dissolution-and-growth chemistry that uses the intrinsic surface oxide of the NC to obtain the Al3+ ions accommodated into the MOF nodes. Changes in the Al NC plasmon resonance provide an intrinsic optical probe of its dissolution and growth kinetics. This same chemistry enables a highly controlled oxidation of the Al NCs, providing a precise method for reducing NC size in a shape-preserving manner. The MOF shell encapsulation of the Al NCs results in increased efficiencies for plasmon-enhanced photocatalysis, which is observed for the hydrogen-deuterium exchange and reverse water-gas shift reactions.