Identification of a family of zinc transporter genes from Arabidopsis that respond to zinc deficiency

Millions of people worldwide suffer from nutritional imbalances of essential metals like zinc. These same metals, along with pollutants like cadmium and lead, contaminate soils at many sites around the world. In addition to posing a threat to human health, these metals can poison plants, livestock, and wildlife. Deciphering how metals are absorbed, transported, and incorporated as protein cofactors may help solve both of these problems. For example, edible plants could be engineered to serve as better dietary sources of metal nutrients, and other plant species could be tailored to remove metal ions from contaminated soils. We report here the cloning of the first zinc transporter genes from plants, the ZIP1, ZIP2, and ZIP3 genes of Arabidopsis thaliana. Expression in yeast of these closely related genes confers zinc uptake activities. In the plant, ZIP1 and ZIP3 are expressed in roots in response to zinc deficiency, suggesting that they transport zinc from the soil into the plant. Although expression of ZIP2 has not been detected, a fourth related Arabidopsis gene identified by genome sequencing, ZIP4, is induced in both shoots and roots of zinc-limited plants. Thus, ZIP4 may transport zinc intracellularly or between plant tissues. These ZIP proteins define a family of metal ion transporters that are found in plants, protozoa, fungi, invertebrates, and vertebrates, making it now possible to address questions of metal ion accumulation and homeostasis in diverse organisms.

Randomised controlled trial of specialist nurse intervention in heart failure

OBJECTIVES

To determine whether specialist nurse intervention improves outcome in patients with chronic heart failure.

DESIGN

Randomised controlled trial.

SETTING

Acute medical admissions unit in a teaching hospital.

PARTICIPANTS

165 patients admitted with heart failure due to left ventricular systolic dysfunction. The intervention started before discharge and continued thereafter with home visits for up to 1 year.

MAIN OUTCOME MEASURES

Time to first event analysis of death from all causes or readmission to hospital with worsening heart failure.

RESULTS

31 patients (37%) in the intervention group died or were readmitted with heart failure compared with 45 (53%) in the usual care group (hazard ratio=0.61, 95% confidence interval 0.33 to 0.96). Compared with usual care, patients in the intervention group had fewer readmissions for any reason (86 v 114, P=0.018), fewer admissions for heart failure (19 v 45, P<0.001) and spent fewer days in hospital for heart failure (mean 3.43 v 7.46 days, P=0.0051).

CONCLUSIONS

Specially trained nurses can improve the outcome of patients admitted to hospital with heart failure.

Subarachnoid hemorrhage diagnosis: lumbar puncture is still needed when the computed tomography scan is normal

OBJECTIVES

To determine the sensitivity of third-generation CT scanners for diagnosed nontraumatic subarachnoid hemorrhage (SAH) and to assess the impact of symptom duration on sensitivity.

METHODS

A retrospective chart review was performed in a university-affiliated tertiary care hospital with an annual ED volume of > 100,000 patients. The target population was all patients who presented to the ED from January 1991 to September 1994 with symptoms suggestive of SAH and who had a final diagnosis of nontraumatic SAH based on either a positive CT scan or positive spinal fluid analysis. Patients referred from outside facilities were included if they had a CT done at the study site. All CT scans were done using third-generation scanners. Official CT scan reports were used to categorize scans as positive or negative.

RESULTS

There were 140 patients identified with SAH, with a mean age of 56 years (range 10-88). The sensitivity of CT in the diagnosis of nontraumatic SAH when performed at or before 12 hours of symptom duration was 100% (80/80), and 81.7% (49/60) after 12 hours of symptom duration (95% CI 95-100% and 69.5-90.4%, respectively; p < 0.0001). Eleven of the 140 patients had a negative CT and positive spinal fluid analysis, yielding an overall sensitivity of 92.1% (129/140).

CONCLUSION

The sensitivity of third-generation CT scans for SAH decreases with time from the onset of symptoms. In this sample population, CT was able to detect all patients scanned < or = 12 hours after symptom onset. Although the study demonstrated good sensitivity of CT scan reports for SAH when the scan was performed after < or = 12 hours of symptom onset, additional real-time experience is needed to better define the potential risk of a missed SAH should this population not receive the customary lumbar puncture examination in the setting of a negative CT scan.

Acute complications in the operative treatment of isolated ankle fractures in patients with diabetes mellitus

Using a computer database, we conducted a retrospective review of all ankle fractures treated at our institution from March 1985 to October 1996. Twenty-one patients with diabetes mellitus and isolated ankle fractures that were treated operatively met all inclusion criteria. Seven had insulin-dependent diabetes, and 14 had non-insulin-dependent diabetes. A randomly selected control group of 46 patients without diabetes who also underwent operative treatment of ankle fractures during this same time period were matched for age, sex, and fracture severity. The complication rate was 43% with 13 complications in nine patients with diabetes. There were seven (15.5%) complications in the control group. Complications in the diabetic group included seven infections (five deep, two superficial) and three losses of fixation. The complications were more severe in our diabetic population, requiring seven additional procedures including two below-knee amputations; a third patient refused an amputation. No additional procedures were required in our control group. All complications in our control group resolved with treatment. The relative risk for postoperative complications in patients with diabetes who sustained ankle fractures that were treated operatively was 2.76 times greater than the control group's (95% confidence interval, 1.57-3.97).

Intravenous infusion of liposomal benzoporphyrin derivative for photodynamic therapy of experimental choroidal neovascularization

OBJECTIVE

To compare the effectiveness of photodynamic therapy to close experimental choroidal neovascularization using an intravenous infusion of liposomal benzoporphyrin derivative (verteporfin) with previous work using a rapid intravenous injection, before initiating clinical trials.

METHODS

Choroidal neovascularization was induced in cynomolgus monkey eyes using argon laser. Liposomal benzoporphyrin derivative was delivered by an intravenous infusion pump for 10 or 32 minutes at a dose of 0.375 mg/kg. Irradiation was performed with 689- or 692-nm laser light (600-mW/cm2 irradiance and 150-J/cm2 fluence) in 7 normal eyes and 11 eyes with choroidal neovascularization between 30 and 105 minutes after the start of dye infusion. Findings were documented by fundus photography, fluorescein angiography, and light and electron microscopy.

RESULTS

Irradiation within 32 to 50 minutes of the start of the fast (10 minutes) or slow (32 minutes) dye infusion resulted in closure of choroidal neovascularization. In normal eyes, this technique caused choriocapillaris closure and retinal pigment epithelium damage with minimal damage to surrounding tissues.

CONCLUSION

Photodynamic therapy using intravenous infusion of liposomal benzoporphyrin derivative selectively closed experimental choroidal neovascularization. This may be a suitable modality for clinical use.

Abnormal regulation of the leptin gene in the pathogenesis of obesity

A subset of obese humans has relatively low plasma levels of leptin. This finding has suggested that in some cases abnormal regulation of the leptin gene in adipose tissue is etiologic in the pathogenesis of the obese state. The possibility that a relative decrease in leptin production can lead to obesity was tested by mating animals carrying a weakly expressed adipocyte specific aP2-human leptin transgene to C57BL/6J ob/ob mice (which do not express leptin). The transgene does not contain the regulatory elements of the leptin gene and is analogous to a circumstance in which the cis elements and/or trans factors regulating leptin RNA production are abnormal. The ob/ob mice carrying the transgene had a plasma leptin level of 1. 78 ng/ml, which is approximately one-half that found in normal, nontransgenic mice (3.72 ng/ml, P < 0.01). The ob/ob animals expressing the leptin transgene were markedly obese though not as obese as ob/ob mice without the transgene. The infertility as well as several of the endocrine abnormalities generally evident in ob/ob mice were normalized in the ob/ob transgenic mice. However, the ob/ob transgenic mice had an abnormal response when placed at an ambient temperature of 4 degreesC, suggesting that different thresholds exist for the different biologic effects of leptin. Leptin treatment of the ob/ob transgenic mice resulted in marked weight loss with efficacy similar to that seen after treatment of wild-type mice. In aggregate these data suggest that dysregulation of leptin gene can result in obesity with relatively normal levels of leptin and that this form of obesity is responsive to leptin treatment.

Absence of soluble leptin receptor in plasma from dbPas/dbPas and other db/db mice

The leptin receptor (Ob-R) is alternatively spliced into at least five different RNAs designated Ob-R(a-e). Ob-R(a-d) predict receptors with a single transmembrane domain, and Ob-Re predicts a secreted form of the receptor. The presence of an approximately 120-kDa soluble leptin receptor in mouse plasma was confirmed by precipitation with leptin-Sepharose beads followed by immunobloting with anti-leptin receptor antibodies. The soluble leptin receptor is larger than that predicted by the primary sequence. Deglycosylation of the receptor with peptide N:glycosidase F results in a decrease in molecular mass to a size consistent with that of the primary sequence. The secreted receptor was present in plasma from wild type mice but was truncated in plasma from db3J/db3J and absent in dbPas/dbPas plasma. Although db3J/db3J mice are known to have a frameshift mutation at amino acid 625, the basis for the mutation in dbPas/dbPas mice was not known. Further studies indicated that dbPas/dbPas mice carry a duplication of exons 4 and 5 of Ob-R. This mutation introduces a premature stop codon into the protein at amino acid 281. The absence of Ob-R in db3J/db3J and dbPas/dbPas mice confirm the identify of the 120-kDa plasma protein as Ob-Re.

Na+-dependent, alpha-adrenergic mobilization of intracellular (mitochondrial) Ca2+ in brown adipocytes

The existence and significance of a hormone-sensitive, rapidly mobilizable intracellular pool of Ca2+ in hamster brown-fat cells was investigated with 45Ca2+-labelling techniques. It was shown that such a pool existed and was probably located within the abundant mitochondria. It was rapidly mobilized by norepinephrine (median effective concentration 50 nM) through alpha-adrenergic mechanisms. The mobilization of Ca2+ from the intracellular stores (mitochondria) required the presence of extracellular Na+, but not of Ca2+, K+ or Mg2+. It is concluded that the experiments are in agreement with a hypothesis linking the mobilization of intracellular Ca2+ pools with an alpha-adrenergically-induced increase in plasma membrane Na+ permeability (observed as a membrane depolarization), and a subsequent activation of the mitochondrial Na+/Ca2+ exchange, leading to mobilization of mitochondrial Ca2+ and the mediation of alpha-adrenergic effects as a result of an elevated cytosolic Ca2+ level.

Conserved promoter elements in the CYP6B gene family suggest common ancestry for cytochrome P450 monooxygenases mediating furanocoumarin detoxification

Despite the fact that Papilio glaucus and Papilio polyxenes share no single hostplant species, both species feed to varying extents on hostplants that contain furanocoumarins. P. glaucus contains two nearly identical genes, CYP6B4v2 and CYP6B5v1, and P. polyxenes contains two related genes, CYP6B1v3 and CYP6B3v2. Except for CYP6B3v2, the substrate specificity of which has not yet been defined, each of the encoded cytochrome P450 monooxygenases (P450s) metabolizes an array of linear furanocoumarins. All four genes are transcriptionally induced in larvae by exposure to the furanocoumarin xanthotoxin; several are also induced by other furanocoumarins. Comparisons of the organizational structures of these genes indicate that all have the same intron/exon arrangement. Sequences in the promoter regions of the P. glaucus CYP6B4v2/CYP6B5v1 genes and the P. polyxenes CYP6B3v2 gene are similar but not identical to the -146 to -97 region of CYP6B1v3 gene, which contains a xanthotoxin-responsive element (XRE-xan) important for basal and xanthotoxin-inducible transcription of CYP6B1v3. Complements of the xenobiotic-responsive element (XRE-AhR) in the dioxin-inducible human and rat CYP1A1 genes also exist in all four promoters, suggesting that these genes may be regulated by dioxin. Antioxidant-responsive elements (AREs) in mouse and rat glutathione S-transferase genes and the Barbie box element (Bar) in the bacterial CYP102 gene exist in the CYP6B1v3, CYP6B4v2, and CYP6B5v1 promoters. Similarities in the protein sequences, intron positions, and xanthotoxin- and xenobiotic-responsive promoter elements indicate that these insect CYP6B genes are derived from a common ancestral gene. Evolutionary comparisons between these P450 genes are the first available for a group of insect genes transcriptionally regulated by hostplant allelochemicals and provide insights into the process by which insects evolve specialized feeding habits.

Distinction between mechanisms underlying alpha 1- and beta-adrenergic respiratory stimulation in brown fat cells

Experimental conditions are described for selective alpha 1- and beta-adrenergic stimulation of the respiration of brown fat cells. The dual agonist norepinephrine was unsuitable as a selective alpha 1-agonist, since unacceptably high concentrations of propranolol were needed to abolish the beta-response. Phenylephrine at 50 microM, in the presence of 5 microM dl-propranolol, was shown to lead to a maximal, selective alpha 1-stimulation, whereas maximal, selective beta-stimulation was achieved with 1 microM isoproterenol in the presence of 5 microM prazosin. The mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) was able to further increase respiration that was already maximally alpha 1-stimulated, but when added before the alpha 1-stimulation, FCCP totally abolished the response. In contrast, FCCP had no effect on the beta-stimulated response. Similarly, oligomycin (an inhibitor of mitochondrial ATP synthesis) inhibited alpha 1-respiration but had a much smaller effect on beta-respiration. Ouabain (an inhibitor of the Na+-K+-ATPase) halved alpha 1-respiration but only induced a small inhibition of beta-respiration. It is concluded that only a small fraction of thermogenesis from beta-adrenergic processes is due to oxidative phosphorylation, whereas alpha 1-respiration is largely due to the oxygen cost of mitochondrial ATP synthesis, and a large fraction of this ATP is apparently used for the restoration of ion gradients.

Presence of a Ca2+-dependent K+ channel in brown adipocytes. Possible role in maintenance of alpha 1-adrenergic stimulation

We have previously demonstrated mobilization of Ca2+ in and efflux of Rb+ (K+) from isolated hamster brown adipocytes as a consequence of norepinephrine stimulation. We have now investigated the adrenoceptor subtype specificity of these responses and found them both to be of the alpha 1-subtype. Further, we have found that the Rb+ (K+) efflux was dependent upon a primary Ca2+ mobilization event in response to the alpha 1-adrenergic stimulation, since the Rb+ efflux could also be demonstrated by the addition of the Ca2+ ionophore A23187 to the cells. The norepinephrine- and A23187-stimulated Rb+ effluxes were both inhibited by the Ca2+-dependent K+-channel blocker apamin. Apamin also significantly attenuated Ca2+ mobilization in cells in response to a submaximal concentration of norepinephrine. We conclude that alpha 1-adrenergic stimulation of brown fat cells leads to a mobilization of intracellular Ca2+ which, in itself or via other mechanisms, leads to an increase in cytosolic Ca2+ concentration which, in turn, activates a Ca2+-dependent K+ channel, leading to a K+ release from these cells. A possible role for this channel to sustain and augment the response to alpha 1-adrenergic stimulation is discussed.

Angiography of fluoresceinated anti-vascular endothelial growth factor antibody and dextrans in experimental choroidal neovascularization

OBJECTIVE

To determine if anti-vascular endothelial growth factor antibody and a range of dextrans with varying diffusion radii and molecular weights are permeable through experimental choroidal neovascularization (CNV).

METHODS

Choroidal neovascularization was induced in 10 cynomolgus monkey retinas by means of argon laser injury. Digital fundus fluorescein angiograms were performed with fluorescein sodium, fluoresceinated IgG antibodies (anti-vascular endothelial growth factor and a control antibody), and fluoresceinated dextrans with molecular weights of 4, 20, 40, 70 and 150 kd. The 40- and 70-kd dextrans straddle the effective diffusion radius of IgG. For each reagent, early and late angiograms were performed in a standardized fashion, with follow-up images obtained to monitor residual fluorescence.

RESULTS

Perfusion of retinal vessels and choroidal vasculature was seen with all reagents. Fluorescein and 4- and 20-kd dextran leaked rapidly from the CNV within the first minute. Angiography with the use of 40-kd dextran and fluoresceinated antibody, either anti-vascular endothelial growth factor or control IgG, showed fluorescence within the CNV that increased during the first 1 to 5 hours, with mild leakage from the CNV. By 24 hours, fluorescence in the CNV was minimal, although in some cases persistent fluorescence in the surrounding tissue was evident up to 2 weeks. The 70-kd dextran showed fluorescence within the CNV and leakage in 1 of 3 eyes. The 150-kd dextran showed fluorescence within the CNV but did not demonstrate leakage.

CONCLUSIONS

Fluoresceinated antibodies and dextran with smaller effective diffusion radii showed CNV perfusion and leakage. Dextrans with larger effective diffusion radii (70 kd and 150 kd) perfused into CNV but did not show leakage consistently.

CLINICAL RELEVANCE

Determining the permeablity of antibodies and molecules of similar size through CNV can help ascertain the feasibility of using intravenously administered antibodies against angiogenic growth factors as a future treatment for choroidal neovascularization.

Primary reticulum cell sarcoma of the brain in a renal transplantation recipient

✓ A case of primary reticulum cell sarcoma of the brain (microgliomatosis) is reported in a kidney transplant recipient treated with immunosuppressants, the second such case seen at this institution. Hypotheses for the mechanism of lymphoma development in this situation are reviewed, and the remarkable predilection for the brain is pointed out.

Intraoperative neurosurgical ultrasound: transdural and transfontanelle applications

High-resolution real-time ultrasound scanning of 54 patients was performed with a sector scanner during a variety of neurological procedures. Scans obtained at the time of craniotomy were successful in characterizing and localizing tumors, abscesses, arteriovenous malformations, and hematomas within the brain of 15 of 16 adult patients. One attempt to visualize a brain cyst through a 15-mm burr hole was unsuccessful. Scanning of 37 infants and young children was performed through the anterior fontanelle during placement of ventricular shunts. This allowed for the accurate placement of shunts in all patients and resulted in fewer short-term and long-term complications. Intraoperative ultrasound is a practical and highly effective means of providing intraoperative localization of intracranial anatomy and disease.

The Porphyromonas gingivalis hemagglutinins HagB and HagC are major mediators of adhesion and biofilm formation

Porphyromonas gingivalis is a bacterium associated with chronic periodontitis that possesses a family of genes encoding hemagglutinins required for heme acquisition. In this study we generated ΔhagB and ΔhagC mutants in strain W83 and demonstrate that both hagB and hagC are required for adherence to oral epithelial cells. Unexpectedly, a double ΔhagB/ΔhagC mutant had less severe adherence defects than either of the single mutants, but was found to exhibit increased expression of the gingipain-encoding genes rgpA and kgp, suggesting that a ΔhagB/ΔhagC mutant is only viable in populations of cells that exhibit increased expression of genes involved in heme acquisition. Disruption of hagB in the fimbriated strain ATCC33277 demonstrated that HagB is also required for stable attachment of fimbriated bacteria to oral epithelial cells. Mutants of hagC were also found to form defective single and multi-species biofilms that had reduced biomass relative to biofilms formed by the wild-type strain. This study highlights the hitherto unappreciated importance of these genes in oral colonization and biofilm formation.

The effect of interscapular brown adipose tissue removal on body-weight and cold response in the mouse

1. The removal of the interscapular brown adipose tissue (IBAT) led to an increase in body-weight of normal, lean mice as compared to anaesthetized controls. 2. No significant difference in food consumption could be detected between the two groups of mice over the period of the experiment. 3. Fat extraction of the whole carcasses with chloroform:methanol showed a statistically significant increase in fat content in the animals without IBAT. 4. There was no apparent failure in the operated animals to sustain core temperature when exposed to a cold stress situation (4 degrees for 24 h). 5. There was no difference in the wet weight, protein content or cytochrome oxidase content of the dorso-cervical brown adipose tissue (DCBAT) between operated and control mice. This is indicative of a lack of proliferation of other brown adipose tissue sites in the operated mice in response to the removal of the IBAT. 6. It is suggested that brown adipose tissue is implicated in dietary thermogenesis in the mouse.

Clinical ethicists' perspectives on organisational ethics in healthcare organisations

BACKGROUND

Demand for organisational ethics capacity is growing in health organisations, particularly among managers. The role of clinical ethicists in, and perspective on, organisational ethics has not been well described or documented in the literature.

OBJECTIVE

To describe clinical ethicists' perspectives on organisational ethics issues in their hospitals, their institutional role in relation to organisational ethics, and their perceived effectiveness in helping to address organisational ethics issues.

DESIGN AND SETTING

Qualitative case study involving semi-structured interviews with 18 clinical ethicists across 13 health organisations in Toronto, Canada.

RESULTS

From the clinical ethicists' perspective, the most pressing organisational ethics issues in their organisations are: resource allocation, staff moral distress linked to the organisation's moral climate, conflicts of interest, and clinical issues with a significant organisational dimension. Clinical ethicists were consulted in particular on issues related to staff moral distress and clinical issues with an organisational dimension. Some ethicists described being increasingly consulted on resource allocation, conflicts of interest, and other corporate decisions. Many clinical ethicists felt they lacked sufficient knowledge and understanding of organisational decision-making processes, training in organisational ethics, and access to organisational ethics tools to deal effectively with the increasing demand for organisational ethics support.

CONCLUSION

Growing demand for organisational ethics expertise in healthcare institutions is reshaping the role of clinical ethicists. Effectiveness in organisational ethics entails a re-evaluation of clinical ethics training to include capacity building in organisational ethics and organisational decision-making processes as a complement to traditional clinical ethics education.

Incidence and occupational pattern of leukaemias, lymphomas, and testicular tumours in western Ireland over an 11 year period

STUDY OBJECTIVE

To determine incidence of the following malignancies, testicular tumours, all leukaemias and all lymphomas in the West of Ireland in an 11 year period. Secondly, to examine the relation between disease patterns and available occupational data in male subjects of working age.

DESIGN

A census survey of all cases occurring in the three counties in the Western Health Board (WHB) area, Galway, Mayo and Roscommon, for the 11 year period 1980 to 1990 inclusive. Average annual age standardised incidence rates for the period were calculated using the 1986 census data. Rates for the area are compared with rates from the southern region of Ireland, which had a tumour registry. Trends over the time period are evaluated. All male subjects for whom occupational data were available were categorised using the Irish socioeconomic group classification and incidence rates by occupation were compared using the standardised incidence ratio method. In one of the counties, Galway, a detailed occupational history of selected cases and an age matched control group was also elicited through patients' general practitioners.

SETTING

All available case records in the West of Ireland.

RESULTS

There are no national incidence records for the period. Compared with data from the Southern Tumour Registry, the number of cases of women with myeloid leukaemias was significantly lower. Male leukaemia rates were significantly lower as a group (SIR 84 (95% CI 74, 95) but not when considered as individual categories. Regression analysis revealed an increasing trend in the number of new cases of non-Hodgkin's lymphoma among both men (r = 0.47, p = 0.02) and women (r = 0.90, p = 0.0001) and of chronic lymphocytic leukaemia in men (r = 0.77, p = 0.005) and women (r = 0.68 p = 0.02) in the WHB region over the last decade. Four hundred and fifty six male cases over the age of 15 years were identified and adequate occupational information was available for 74% of these. Standardised incidence ratios of testicular tumours 100, 938) and agriworkers other than farmers (SIR 377, 95% CI 103, 967). There were also significantly increased incidence ratios for both non-Hodgkin's lymphoma (SIR 169, 95% CI 124, 266) and three categories of leukaemias among farmers. Hodgkin's disease and acute myeloid leukaemias were significantly increased among semi-skilled people. Interview data with 90 cases and 54 controls of both sexes revealed that among farmers, cases (n = 31) were significantly less likely than controls (n = 20) to use tractor mounted spraying techniques (OR = 0.19 (95% CI 0.04, 0.80)) and less likely to wear protective masks (OR 0.22 (95% CI 0.05, 0.84)).

CONCLUSIONS

Trends of increase in non-Hodgkin's lymphoma and some leukaemias are consistent with studies elsewhere. The study provides further evidence of the relation between agricultural work and certain lymphoproliferative cancers. The possible carcinogenic role of chemicals used in agricultural industries must be considered as an explanation.

Pre-surgical trial of the AKT inhibitor MK-2206 in patients with operable invasive breast cancer: a New York Cancer Consortium trial

INTRODUCTION

The PI3K/AKT/mTOR pathway is an oncogenic driver in breast cancer (BC). In this multi-center, pre-surgical study, we evaluated the tissue effects of the AKT inhibitor MK-2206 in women with stage I-III BC.

MATERIALS AND METHODS

Two doses of weekly oral MK2206 were administered at days - 9 and - 2 before surgery. The primary endpoint was reduction of pAktSer473 in breast tumor tissue from diagnostic biopsy to surgery. Secondary endpoints included changes in PI3K/AKT pathway tumor markers, tumor proliferation (ki-67), insulin growth factor pathway blood markers, pharmacokinetics (PK), genomics, and MK-2206 tolerability. Paired t tests were used to compare biomarker changes in pre- and post-MK-2206, and two-sample t tests to compare with prospectively accrued untreated controls.

RESULTS

Despite dose reductions, the trial was discontinued after 12 patients due to grade III rash, mucositis, and pruritus. While there was a trend to reduction in pAKT after MK-2206 (p = 0.06), there was no significant change compared to controls (n = 5, p = 0.65). After MK-2206, no significant changes in ki-67, pS6, PTEN, or stathmin were observed. There was no significant association between dose level and PK (p = 0.11). Compared to controls, MK-2206 significantly increased serum glucose (p = 0.02), insulin (p < 0.01), C-peptide (p < 0.01), and a trend in IGFBP-3 (p = 0.06).

CONCLUSION

While a trend to pAKT reduction after MK-2206 was observed, there was no significant change compared to controls. However, the accrued population was limited, due to toxicity being greater than expected. Pre-surgical trials can identify in vivo activity in the early drug development, but side effects must be considered in this healthy population.

Unusual cause of a perforated stomach

A case of gastric perforation 2 months following insertion of a gastric balloon is reported. The literature is reviewed regarding the complications and success rates inherent in such balloon devices. This is the first case report of an intra-gastric balloon causing gastric perforation.

Alpha 1-adrenergic stimulation of Cl- efflux in isolated brown adipocytes

Unidirectional 36Cl- efflux from preloaded isolated brown adipocytes was studied. A norepinephrine-stimulated 36Cl- efflux pathway was found which approximately doubled the rate of 36Cl- efflux from the cells. The response to norepinephrine was fully inhibited by the alpha 1-adrenergic antagonist prazosin, but was unaffected by the beta-adrenergic antagonist propranolol, showing that norepinephrine stimulated the 36Cl- efflux pathway via the alpha 1-adrenoceptor. The stimulation of 36Cl- efflux could not be mimicked by the Ca2+ ionophore A23187, indicating that the effect was not mediated by elevation of the intracellular Ca2+ level. It is concluded that brown fat cells possess a specific mechanism for alpha 1-adrenergic stimulation of Cl- efflux. The possibility is discussed that this Cl- efflux pathway could be the basis for the early alpha-adrenergic depolarization seen in brown fat cells.

Proteomic modulation in breast tumors after metformin exposure: results from a "window of opportunity" trial

PURPOSE

Reverse Phase Protein Array (RPPA) is a high-throughput antibody-based technique to assess cellular protein activity. The goal of this study was to assess protein marker changes by RPPA in tumor tissue from a pre-surgical metformin trial in women with operable breast cancer (BC).

METHODS

In an open-label trial, metformin 1500-mg PO daily was administered prior to resection in 35 non-diabetic patients with stage 0-III BC, body mass index ≥25 kg/m². For RPPA, formalin-fixed paraffin-embedded (FFPE) samples were probed with 160 antibodies. Paired and two-sample t-tests were performed (p ≤ 0.05). Multiple comparisons were adjusted for by fixing the false discovery rate at 25 %. We evaluated whether pre- and post-metformin changes of select markers by RPPA were identified by immunohistochemistry (IHC) in these samples. We also assessed for these changes by western blot in metformin-treated BC cell lines.

RESULTS

After adjusting for multiple comparisons in the 32 tumors from metformin-treated patients vs. 34 untreated historical controls, 11 proteins were significantly different between cases vs.

CONTROLS

increases in Raptor, C-Raf, Cyclin B1, Cyclin D1, TRFC, and Syk; and reductions in pMAPK^pT202,Y204, JNK^pT183,pT185, Bad^pS112, PKC.alpha^pS657, and Src^pY416. Cyclin D1 change after metformin by IHC was not observed. In cell lines, reductions in JNK^pT183 and Bad^pS112 were seen, with no change in Cyclin D1 or Raptor.

CONCLUSIONS

These results suggest that metformin modulates apoptosis/cell cycle, cell signaling, and invasion/motility. These findings should be assessed in larger metformin trials. If confirmed, associations between these changes and BC clinical outcome should be evaluated. CLINICALTRIALS.

GOV IDENTIFIER

NCT00930579.

Responses to cafeteria feeding in mice after the removal of interscapular brown adipose tissue

Feeding a cafeteria diet to mice resulted in an increased energy intake of approximately 30% and this led to increases in the wet weight, total protein content, and total cytochrome oxidase activity of interscapular and dorso-cervical brown adipose tissue. Surgical removal of interscapular brown adipose tissue, followed by cafeteria feeding, gave rise to an elevation in dorso-cervical brown adipose tissue wet weight, total protein content, and total cytochrome oxidase activity, compared to intact cafeteria-fed mice. Cafeteria feeding with or without the removal of interscapular brown adipose tissue did not lead to significant increases in body weight compared to stock-fed control mice, but both cafeteria-fed groups of mice showed significant elevations in body fat content indicating that the induced hyperphagia led to a relative obesity in the cafeteria-fed groups. The results presented are consistent with an increased thermogenic activity in the brown adipose tissue of cafeteria-fed mice, and the effect of the removal of interscapular brown adipose tissue further indicates the quantitative importance of the tissue in the control of body weight.