Flavonol dioxygenase chemistry mediated by a synthetic nickel superoxide

Nature exploits transition metal centers to enhance and tune the oxidizing power of natural oxidants such as O₂ and H₂O₂. The design and interrogation of synthetic metallocomplexes with similar reactivity to metalloproteins provides one strategy for gaining insight into the mechanistic underpinnings of oxygen-activating enzymes such as oxidases, oxygenases, and dioxygenases like Ni-quercetinase (Ni-QueD). Ni-QueD catalyzes the oxidative ring opening of the polyphenol quercetin, a natural product with antioxidant properties. Herein, we report the synthesis and characterization of Ni(13-DOB), a Ni(II) species complexed by an N4-macrocycle that has been characterized by single crystal X-ray crystallography. Ni(13-DOB) forms a Ni-superoxide intermediate (Ni(13-DOB)O₂^•-) upon treatment with H₂O₂ and Et₃N, as verified by resonance Raman spectroscopy. We demonstrate through UV/vis and LCMS that Ni(13-DOB)O₂^•- is capable of the 1-electron oxidation of flavonols, including both 3-hydroxyflavone (3-HF, the simplest flavonol) and quercetin itself. Incorporation of two O-atoms into the flavonol radical via superoxide from Ni(13-DOB)O₂^•- precedes oxidative cleavage of the flavonol scaffold in each case, consistent with quercetinase ring cleavage by Ni-QueD in Streptomyces sp. FLA. Conversion of 3-HF into 2-hydroxybenzoylbenzoic acid was accomplished with catalytic turnover of Ni(13-DOB) at ambient temperature, as confirmed by HPLC timecourses and GCMS analysis of isotopic labeling studies. The Ni(13-DOB)-mediated oxidative cleavage of quercetin to the corresponding biomimetic phenolic ester was also verified through ¹⁸O-isotopic labeling studies. Through the HPLC characterization of both on- and off-pathway products of flavonol dioxygenation by Ni(13-DOB)O₂^•-, the stringent reaction pathway control provided by enzyme active sites is highlighted.

Hiding in Plain Sight: A Case of Ornithine Transcarbamylase Deficiency Unmasked Post-Liver Transplantation

Ornithine transcarbamylase deficiency represents the most common inherited defect of the urea cycle. This enzyme, predominantly found in the liver, plays a crucial role in recycling free ammonia, with deficiencies often leading to fatal complications. Here, we present the case of a 63-year-old man with alcoholic cirrhosis who underwent orthotopic liver transplantation, gradual worsening of his mental status, and progressive elevation of ammonia levels. Liver allograft function was deemed normal, raising concern for a donor-derived metabolic disorder of the urea cycle. Evaluation of the donor patient's blood revealed that the donor was heterozygous for the OTC gene. Posttransplantation changes in mental status should prompt a clinician to consider the most likely causes; however, once these have been ruled out, it is important to consider the less common causes of metabolic derangements. The rarity of these disorders makes expertise of diagnosis, standardization of evaluation, and treatment strategies challenging.

Abstract P1-05-20: Comparing the frequency and types of genetic aberrations between older and younger women with metastatic breast cancer at the University of North Carolina at Chapel Hill

Background: Targeted therapies have the potential to revolutionize cancer treatment in older adults as they are often oral, convenient, may be better tolerated than cytotoxic chemotherapy, and can be tailored to an individual's biomarker profile. We explore the frequency and distribution of potentially actionable genomic alterations among older (≥65) and younger (<65) patients (pts) with metastatic breast cancer (MBC).

Method: Next generation genetic sequencing (UNCseq™) of a dynamic panel of target genes was prospectively offered to pts with MBC treated at the University of North Carolina at Chapel Hill (UNC). DNA libraries were prepared separately from a retrieved archival FFPE tumor sample and a matched normal sample from each pt. Relevant targets were enriched by custom Agilent SureSelect hybrid capture baits using standard protocols. Samples were sequenced on Illumina HiSeq 2000/2500 platforms. Mutational findings were reviewed by a molecular tumor board; variants identified to be potentially actionable underwent confirmatory testing in a CLIA approved laboratory. Confirmed findings were inserted into the pt's EMR accessible by both the pt and the treating oncologist. Two-sided Fisher's exact test was used to compare percentages between age-specific groups.

Results: As of 3/31/16, results were available for 140 pts. 19% were 65 years or older. Breast cancer clinical subtypes were: HR+/HER2- 49%, HER2+ (HR any) 17%, TN 34% and metastatic location was: bone only 5%, visceral only 44%, bone & visceral 51%; no significant differences were observed between older and younger age groups. Older pts were more likely to be Caucasian compared to younger patients (92% v 75%, p=0.06). Overall, older patients had a higher total number of mutations compared to younger patients (see Table) (p=0.04). Mutation types were similar between age groups, although a trend for more PIK3CA mutations among older patients was seen (37% v 20%, p=0.07).

Observed Mutations by Age. ≥ 65 years (%) N=27< 65 years (%) N=113pNumber of Mutations   01127.0414849.0423320.04374.04Type of mutation   PIK3CA3720.07CCND179.99NF-1115.37FGFR144.99PTEN49.69EGFR04.99

Conclusion: Genomic alterations may allow therapeutic tailoring in both older and younger patients with breast cancer. In this cohort with metastatic disease, older patients had significantly more mutations, but no clear difference in mutational types was seen by age. The relative small number of older pts in this cohort limits generalization, but supports the need for more extensive characterization of molecular aberrations among older pts with metastatic breast cancer in the new era of targeted therapy.

Research support by the University Cancer Research Fund, NCI Breast Cancer SPORE grant (CA58223), John A. Hartford Foundation and Susan G. Komen Foundation.

Citation Format: Jolly TA, Grilley-Olson JE, Deal AM, Ivanova A, Hayward MC, Benbow JM, Parker JS, Patel NM, Eberhard DA, Weck KE, Mieczkowski P, Dees EC, Muss HD, Reeder-Hayes KE, Earp HS, Sharpless NE, Carey LA, Hayes DN, Anders CK. Comparing the frequency and types of genetic aberrations between older and younger women with metastatic breast cancer at the University of North Carolina at Chapel Hill [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-05-20.

Abstract PD6-07: Genomic sequencing in metastatic breast cancer patients to inform clinical practice at the University of North Carolina at Chapel Hill

Background: An increasing number of molecularly-targeted therapies for metastatic breast cancer (MBC) are clinically-available (approved and investigational). These anti-cancer agents target specific molecular abnormalities such as mutated, amplified, deleted, or rearranged genes. Reporting of unique tumor genetic alterations is not included in routine clinical/diagnostic panels. In MBC, knowledge of mutational status may foster efficient transitions in clinical care and trial enrollment at disease progression. We describe the development and implementation of a clinically-integrated genomic sequencing program and report how information regarding targetable genomic aberrations in MBC patients (pts) is used to improve clinical practice in an academic setting.

Methods: Genomic sequencing of investigative biomarkers was prospectively offered to pts with MBC. DNA libraries were prepared separately from a retrieved archival FFPE tumor sample and a matched normal sample from each pt. Relevant targets were enriched by custom Agilent SureSelect hybrid capture baits using standard protocols. Samples were sequenced on Illumina HiSeq 2000/2500 platforms. Mutational findings were reviewed by a molecular tumor board (MTB); variants identified to be potentially actionable underwent confirmatory testing in a CLIA-approved laboratory. Confirmed findings were inserted into the pt's EMR accessible by both the pt and the treating oncologist.

Results: Of the 725 MBC pts seen at UNC since 1/1/2012, 194 (27%) contributed samples for genomic sequencing. Of those whose tumors were sequenced, average age at MBC diagnosis was 54 (25 - 91); 73% were Caucasian, 16% African American. De novo MBC accounted for 39 (20%) sequenced pts. Of sequenced patients, sites of metastatic disease included bone only (7%), visceral only (46%), and both bone and visceral (47%). Approximately 1/3 of pts were consented for sequencing at time of initial MBC diagnosis, 1/4 after 1st line therapy for MBC, and the remaining at or beyond their 2nd line. In total, 131 (68%) pts have sequencing results available of which 43% of pts had reportable mutations deemed actionable by the MTB. Specific mutations and observed frequency by subtype are shown below. Pts (19%) whose tumors were sequenced were more commonly enrolled in a therapeutic clinical trial for MBC, a higher rate than seen in the non-sequenced group (7%) (p<0.001). To date, 27% of pts' tumors harbored an alteration that is an eligibility requirement for a molecularly-targeted therapeutic trial accruing pts at UNC.

Observed Mutation by Clinical Subype Genes Total # (56 pts)HR+/HER2- (25 pts)HER2+ (13 pts)TNBC (18pts)PIK3CA15933TP5315456CCND19531NF-14103FGFR13300PTEN3012KRAS2011MDM22110PIK3R12002ROS12011TSC12011Other*14518TOTAL73281728*Mutations observed only once

Conclusion: Preemptive genomic sequencing can be integrated into the clinical and operational practice of a comprehensive cancer center. Currently this research tool and program provides valuable information that has the potential to foster both clinical trial eligibility and/or enrollment. With longer follow-up, we hope such an approach ultimately will improve patient outcomes.

Citation Format: Grilley-Olsen J, Keith KC, Hayward M, Dees EC, Deal A, Ivanova A, Benbow JM, Parker J, Patel NM, Eberhard D, Mieczkowski P, Weck KE, Hayes DN, Muss H, Jolly T, Reeder-Hayes K, Earp HS, Sharpless N, Carey L, Anders CK. Genomic sequencing in metastatic breast cancer patients to inform clinical practice at the University of North Carolina at Chapel Hill. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD6-07.

End-stage renal disease in African Americans with lupus nephritis is associated with APOL1

OBJECTIVE

Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE) that exhibits familial aggregation and may progress to end-stage renal disease (ESRD). LN is more prevalent among African Americans than among European Americans. This study was undertaken to investigate the hypothesis that the apolipoprotein L1 gene (APOL1) nephropathy risk alleles G1/G2, common in African Americans and rare in European Americans, contribute to the ethnic disparity in risk.

METHODS

APOL1 G1 and G2 nephropathy alleles were genotyped in 855 African American SLE patients with LN-ESRD (cases) and 534 African American SLE patients without nephropathy (controls) and tested for association under a recessive genetic model, by logistic regression.

RESULTS

Ninety percent of the SLE patients were female. The mean ± SD age at SLE diagnosis was significantly lower in LN-ESRD cases than in SLE non-nephropathy controls (27.3 ± 10.9 years versus 39.5 ± 12.2 years). The mean ± SD time from SLE diagnosis to development of LN-ESRD in cases was 7.3 ± 7.2 years. The G1/G2 risk alleles were strongly associated with SLE-ESRD, with 25% of cases and 12% of controls having 2 nephropathy alleles (odds ratio [OR] 2.57, recessive model P = 1.49 × 10(-9)), and after adjustment for age, sex, and ancestry admixture (OR 2.72, P = 6.23 × 10(-6)). The age-, sex-, and admixture-adjusted population attributable risk for ESRD among patients with G1/G2 polymorphisms was 0.26, compared to 0.003 among European American patients. The mean time from SLE diagnosis to ESRD development was ∼2 years earlier among individuals with APOL1 risk genotypes (P = 0.01).

CONCLUSION

APOL1 G1/G2 alleles strongly impact the risk of LN-ESRD in African Americans, as well as the time to progression to ESRD. The high frequency of these alleles in African Americans with near absence in European Americans explains an important proportion of the increased risk of LN-ESRD in African Americans.

Lymphoma risk in systemic lupus: effects of disease activity versus treatment

OBJECTIVE

To examine disease activity versus treatment as lymphoma risk factors in systemic lupus erythematosus (SLE).

METHODS

We performed case-cohort analyses within a multisite SLE cohort. Cancers were ascertained by regional registry linkages. Adjusted HRs for lymphoma were generated in regression models, for time-dependent exposures to immunomodulators (cyclophosphamide, azathioprine, methotrexate, mycophenolate, antimalarial drugs, glucocorticoids) demographics, calendar year, Sjogren's syndrome, SLE duration and disease activity. We used adjusted mean SLE Disease Activity Index scores (SLEDAI-2K) over time, and drugs were treated both categorically (ever/never) and as estimated cumulative doses.

RESULTS

We studied 75 patients with lymphoma (72 non-Hodgkin, three Hodgkin) and 4961 cancer-free controls. Most lymphomas were of B-cell origin. As is seen in the general population, lymphoma risk in SLE was higher in male than female patients and increased with age. Lymphomas occurred a mean of 12.4 years (median 10.9) after SLE diagnosis. Unadjusted and adjusted analyses failed to show a clear association of disease activity with lymphoma risk. There was a suggestion of greater exposure to cyclophosphamide and to higher cumulative steroids in lymphoma cases than the cancer-free controls.

CONCLUSIONS

In this large SLE sample, there was a suggestion of higher lymphoma risk with exposure to cyclophosphamide and high cumulative steroids. Disease activity itself was not clearly associated with lymphoma risk. Further work will focus on genetic profiles that might interact with medication exposure to influence lymphoma risk in SLE.

Cancer risk in systemic lupus: an updated international multi-centre cohort study

OBJECTIVE

To update estimates of cancer risk in SLE relative to the general population.

METHODS

A multisite international SLE cohort was linked with regional tumor registries. Standardized incidence ratios (SIRs) were calculated as the ratio of observed to expected cancers.

RESULTS

Across 30 centres, 16,409 patients were observed for 121,283 (average 7.4) person-years. In total, 644 cancers occurred. Some cancers, notably hematologic malignancies, were substantially increased (SIR 3.02, 95% confidence interval, CI, 2.48, 3.63), particularly non-Hodgkin's lymphoma, NHL (SIR 4.39, 95% CI 3.46, 5.49) and leukemia. In addition, increased risks of cancer of the vulva (SIR 3.78, 95% CI 1.52, 7.78), lung (SIR 1.30, 95% CI 1.04, 1.60), thyroid (SIR 1.76, 95% CI 1.13, 2.61) and possibly liver (SIR 1.87, 95% CI 0.97, 3.27) were suggested. However, a decreased risk was estimated for breast (SIR 0.73, 95% CI 0.61-0.88), endometrial (SIR 0.44, 95% CI 0.23-0.77), and possibly ovarian cancers (0.64, 95% CI 0.34-1.10). The variability of comparative rates across different cancers meant that only a small increased risk was estimated across all cancers (SIR 1.14, 95% CI 1.05, 1.23).

CONCLUSION

These data estimate only a small increased risk in SLE (versus the general population) for cancer over-all. However, there is clearly an increased risk of NHL, and cancers of the vulva, lung, thyroid, and possibly liver. It remains unclear to what extent the association with NHL is mediated by innate versus exogenous factors. Similarly, the etiology of the decreased breast, endometrial, and possibly ovarian cancer risk is uncertain, though investigations are ongoing.

(1-34) Parathyroid hormone infusion acutely lowers fibroblast growth factor 23 concentrations in adult volunteers

BACKGROUND AND OBJECTIVES

Fibroblast growth factor 23 (FGF23) regulates phosphorus and vitamin D metabolism. Parathyroid hormone (PTH) infusion for 24 hours stimulated FGF23 secretion in healthy volunteers. The extent to which this was due to a direct stimulatory effect of PTH versus an indirect effect of increasing 1,25-dihydroxyvitamin D [1,25(OH)(2)D] levels was unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Changes in FGF23 in 26 adults undergoing 6-hour (1-34) PTH infusion were examined, focusing particularly on the effects of PTH on FGF23 in the early period of infusion before sustained increases in 1,25(OH)(2)D.

RESULTS

FGF23 levels declined in parallel with serum phosphate during infusion (P<0.05 for both), with both analytes decreasing within the first hour and reaching their respective nadirs at 6 hours. These changes were observed despite no change in 1,25(OH)(2)D levels during the first hour and a significant increase in 1,25(OH)(2)D from baseline after 6 hours (P<0.001). There were no differences in these responses by race. However, modest racial differences in the phosphaturic response to (1-34) PTH were observed (P=0.04 for interaction), with a higher rate of increase in fractional phosphate excretion in blacks than in whites.

CONCLUSIONS

During short-term (1-34) PTH infusion, FGF23 levels decreased in parallel with serum phosphate levels and despite significant increases in 1,25(OH)(2)D. When coupled with the results of prior longer-term infusion studies, these findings suggest that acute increases in PTH initially act to suppress FGF23 secretion, perhaps to mitigate urinary phosphate losses, before the stimulatory effect of 1,25(OH)(2)D on FGF23 eventually begins to predominate.

Determination of polyphenols and free radical scavenging activity of Tephrosia purpurea linn leaves (Leguminosae)

BACKGROUND

Leaves of Tephrosia purpurea Linn. (sarpankh), belonging to the family Leguminaceae, are used for the treatment of jaundice and are also claimed to be effective in many other diseases. This research work was undertaken to investigate the in vitro antioxidant activity of aqueous and ethanolic extracts of the leaves.

METHOD

The therapeutic effects of tannins and flavonoids can be largely attributed to their antioxidant properties. So, the quantitative determinations were undertaken. All the methods are based on UV-spectrophotometric determination.

RESULT

The total phenolic content of aqueous and ethanolic extracts showed the content values of 9.44 ± 0.22% w/w and 18.44 ± 0.13% w/w, respectively, and total flavonoid estimation of aqueous and ethanolic extracts showed the content values of 0.91 ± 0.08% w/w and 1.56 ± 0.12%w/w, respectively, for quercetin and 1.85 ± 0.08% w/w and 2.54 ± 0.12% w/w, respectively, for rutin. Further investigations were carried out for in vitro antioxidant activity and radical scavenging activity by calculating its percentage inhibition by means of IC(50)values, all the extracts' concentrations were adjusted to fall under the linearity range and here many reference standards like tannic acid, gallic acid, quercetin, ascorbic acid were taken for the method suitability.

CONCLUSION

The results revealed that leaves of this plant have antioxidant potential. The results also show the ethanolic extract to be more potent than the aqueous decoction which is claimed traditionally. In conclusion, T. purpurea Linn. (Leguminosae) leaves possess the antioxidant substance which may be responsible for the treatment of jaundice and other oxidative stress-related diseases.

HPTLC Method for the Simultaneous Estimation of Valsartan and Hydrochlorothiazide in Tablet Dosage Form

A simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed and validated for the simultaneous estimation of valsartan and hydrochlorothiazide in combined dosage forms. The stationary phase used was precoated silica gel 60F₂₅₄. The mobile phase used was a mixture of chloroform: methanol: toluene: glacial acetic acid (6:2:1:0.1 v/v/v/v). The detection of spots were carried out at 260 nm. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 300 to 800 ng/spot for valsartan and 100 to 600 ng/spot for hydrochlorothiazide. The limit of detection and the limit of quantification for the valsartan were found to be 100 and 300 ng/spot respectively and for hydrochlorothiazide 30 and 100 ng/spot respectively. The proposed method can be successfully used to determine the drug content of marketed formulation.

Stability-indicating Simultaneous HPTLC Method for Olanzapine and Fluoxetine in Combined Tablet Dosage Form

A rapid, selective and stability-indicating high performance thin layer chromatographic method was developed and validated for the simultaneous estimation of olanzapine and fluoxetine in combined tablet dosage form. Olanzapine and fluoxetine were chromatographed on silica gel 60 F₂₅₄ TLC plate using methanol:toluene (4:2 v/v) as the mobile phase and spectrodensitometric scanning-integration was performed at a wavelength of 233 nm using a Camag TLC Scanner III. This system was found to give compact spots for both olanzapine (R_f value of 0.63±0.01) and fluoxetine (R_f value of 0.31±0.01). The polynomial regression data for the calibration plots showed good linear relationship with r²=0.9995 in the concentration range of 100-800 ng/spot for olanzapine and 1000-8000 ng/spot for fluoxetine with r²=0.9991. The method was validated in terms of linearity, accuracy, precision, recovery and specificity. The limit of detection and the limit of quantification for the olanzapine were found to be 30 and 100 ng/spot, respectively and for fluoxetine 300 and 1000 ng/spot, respectively. Olanzapine and fluoxetine were degraded under acidic, basic and oxidation degradation conditions which showed all the peaks of degraded product were well resolved from the active pharmaceutical ingredient. Both drugs were not further degraded after thermal and photochemical degradation. The method was found to be reproducible and selective for the simultaneous estimation of olanzapine and fluoxetine. As the method could effectively separate the drugs from their degradation products, it can be employed as a stability-indicating method.

Vitamin D deficiency, inflammation, and albuminuria in chronic kidney disease: complex interactions

OBJECTIVE

Vitamin D may promote cardiovascular health in general population and in chronic kidney disease (CKD) through inhibition of the renin-angiotensin system and anti-inflammatory effects. Although proteinuria is a marker of kidney and cardiovascular disease, few studies have examined vitamin D levels, inflammation, and proteinuria simultaneously in CKD. We evaluated the relationship between calcidiol (25D), calcitriol (1,25D), inflammation, and albuminuria in Study of Early Evaluation of Kidney Disease, a multicenter CKD cohort.

DESIGN

A cross-sectional study was carried out.

PARTICIPANTS

A total of 1,847 participants were studied, of which 387 were randomly selected for inflammatory biomarker assessment. PREDICTORS AND OUTCOMES: The primary predictors were 25D and 1,25D. The outcome was albuminuria (urine albumin to creatinine ratio [UACR]: >30 mg/g).

RESULTS

Albuminuric patients were more likely to have decreased 25D and 1,25D levels and higher interleukin-6 (IL-6) levels compared with normoalbuminuric patients. The lowest tertiles of 25D and 1,25D were associated with 2 to 3 times increased odds of albuminuria compared with the highest tertiles when adjusted for age, gender, race, systolic blood pressure, and diabetes (OR for 25D: 3.0; 95% CI: 1.3 to 7.0; OR for 1,25D: 2.6; 95% CI: 1.7 to 3.9). In analogous linear regression models, 25D and 1,25D were significantly associated with log UACR (P < .0001, for both). In participants for whom inflammatory markers were measured, demographics-adjusted linear regression models that included IL-6 described attenuation of the relationship between 25D, 1,25D, and UACR.

CONCLUSIONS

Low 25D and 1,25D levels are independently associated with albuminuria. IL-6 may be an important intermediary between vitamin D deficiency and albuminuria, or vitamin D deficiency may contribute to inflammation and subsequent albuminuria.

Vibrio cholerae non-O1 infection in cirrhotics: case report and literature review

Vibrio species are ubiquitous in the marine environment and can cause severe infections in cirrhotic patients. Patients with liver disease should be warned about the potential dangers of consuming raw or undercooked seafood, and avoiding exposure of wounds to seawater. We report a case of severe sepsis from Vibrio cholerae non-O1 in a patient with cirrhosis awaiting orthotopic liver transplant. This case is aimed to advise clinicians about the importance of V. cholerae subtypes, and non-cholera Vibrio species infections in cirrhotic patients, highlighting the need to educate these patients to stay away from undercooked seafood.

Tumour necrosis factor and PI3-kinase control oestrogen receptor alpha protein level and its transrepression function

Oestrogen receptor alpha (ERα) is an oestrogen-activated transcription factor, which regulates proliferation and differentiation of mammary epithelial cells by activating or repressing gene expression. ERα is a critical prognostic indicator and a therapeutic target for breast cancer. Patients with tumours that express higher level of ERα have better prognosis than patients with tumours that are ERα negative or express lower level of ERα. Better prognosis in ERα-positive patients is believed to be due to repression of proinvasive gene expression by ERα. Oestrogen receptor alpha represses gene expression by transrepressing the activity of the transcription factors such as nuclear factor-kappaB or by inducing the expression of transcriptional suppressors such as MTA3. In this report, we show that ERα transrepresses the expression of the proinvasive gene interleukin 6 (IL-6) in ERα-negative MDA-MB-231 breast cancer cells stably overexpressing ERα. Using these cells as well as ERα-positive MCF-7 and ZR-75-1 cells, we show that tumour necrosis factor alpha (TNFα) and the phosphatidylinositol-3-kinase (PI3-kinase) modulate transrepression function of ERα by reducing its stability. From these results, we propose that TNFα expression or PI3-kinase activation lead to reduced levels of ERα protein in cancer cells and corresponding loss of transrepression function and acquisition of an invasive phenotype.

Twist elasticity and anchoring in a lamellar nematic phase

Electro-optic measurements were performed on a lamellar nematic phase in which the mesogenic moieties lie in lamellae that are separated by partially perfluorinated side groups. The twist elastic constant K22, viscosity gamma(1), and the quadratic and quartic anchoring strength coefficients are reported. K22 and gamma(1) are found to be considerably smaller than that of typical three-dimensional nematics. The small K22 is due to the greatly weakened interactions between the spatially separated lamellae.

Reentrant synclinic phase in an electric-field-temperature-phase diagram for enantiomeric mixtures of an antiferroelectric liquid crystal

The threshold electric field E(th) for a transition from the anticlinic to the synclinic phase of enantiomeric mixtures of the liquid crystal TFMHPOBC was measured as a function of temperature T and enantiomeric excess X. For small X the phase boundary curve on a temperature-electric-field phase diagram exhibits the phase sequence synclinic-anticlinic-reentrant synclinic on decreasing the temperature. At one point along the curve the quantity dT/dE--> infinity. For large values of enantiomeric excess a reentrant phase is not observed. The results are discussed using a simple phenomenological theory that accounts for layer-layer interactions, such that the electric-field-induced transition to the synclinic phase, although completed by solitary-wave propagation, is facilitated by a percolation mechanism.

Comparison of transconjunctival versus subciliary approaches for orbital fractures: a review of 60 cases

The increasing emphasis on open reduction in the management of orbital fractures has led to an extensive debate as to which approach provides adequate exposure for these fractures. This retrospective study compares the exposure provided and the rate of complications between transconjunctival and subciliary incisions for orbital rim and floor fractures. The charts of 55 patients with orbital fractures, treated with open reduction and internal fixation, were reviewed. A total of 30 subciliary and 30 transconjunctival incisions had been performed, and the adequacy of exposure as well as intraoperative and postoperative complication rates were compared. The authors found a higher rate of complications with the subciliary approach and, therefore, advocate the use of a transconjunctival incision for the management of orbital fractures.

Stability of connected cylindrical liquid bridges

Two cylindrical liquid bridges, with a conduit to facilitate flow of liquid from one bridge to the other, were levitated against gravity in a magnetic field gradient. The stability limit of the bridges subjected to near zero total body force was measured as a function of their slenderness ratios, and found to be in good agreement with theoretical predictions.

Phosphatidylinositol 3-kinase/AKT-mediated activation of estrogen receptor alpha: a new model for anti-estrogen resistance

Estrogen receptors (ERs) mediate most of the biological effects of estrogen in mammary and uterine epithelial cells by binding to estrogen response elements in the promoter region of target genes or through protein-protein interactions. Anti-estrogens such as tamoxifen inhibit the growth of ER-positive breast cancers by reducing the expression of estrogen-regulated genes. However, anti-estrogen-resistant growth of ER-positive tumors remains a significant clinical problem. Here we show that phosphatidylinositol (PI) 3-kinase and AKT activate ERalpha in the absence of estrogen. Although PI 3-kinase increased the activity of both estrogen-independent activation function 1 (AF-1) and estrogen-dependent activation function 2 (AF-2) of ERalpha, AKT increased the activity of only AF-1. PTEN and a catalytically inactive AKT decreased PI 3-kinase-induced AF-1 activity, suggesting that PI 3-kinase utilizes AKT-dependent and AKT-independent pathways in activating ERalpha. The consensus AKT phosphorylation site Ser-167 of ERalpha is required for phosphorylation and activation by AKT. In addition, LY294002, a specific inhibitor of the PI 3-kinase/AKT pathway, reduced phosphorylation of ERalpha in vivo. Moreover, AKT overexpression led to up-regulation of estrogen-regulated pS2 gene, Bcl-2, and macrophage inhibitory cytokine 1. We demonstrate that AKT protects breast cancer cells from tamoxifen-induced apoptosis. Taken together, these results define a molecular link between activation of the PI 3-kinase/AKT survival pathways, hormone-independent activation of ERalpha, and inhibition of tamoxifen-induced apoptotic regression.

Physiological control of smooth muscle-specific gene expression through regulated nuclear translocation of serum response factor

Prolonged serum deprivation induces a structurally and functionally contractile phenotype in about 1/6 of cultured airway myocytes, which exhibit morphological elongation and accumulate abundant contractile apparatus-associated proteins. We tested the hypothesis that transcriptional activation of genes encoding these proteins accounts for their accumulation during this phenotypic transition by measuring the transcriptional activities of the murine SM22 and human smooth muscle myosin heavy chain promoters during transient transfection in subconfluent, serum fed or 7 day serum-deprived cultured canine tracheal smooth muscle cells. Contrary to our expectation, SM22 and smooth muscle myosin heavy chain promoter activities (but not viral murine sarcoma virus-long terminal repeat promoter activity) were decreased in long term serum-deprived myocytes by at least 8-fold. Because serum response factor (SRF) is a required transcriptional activator of these and other smooth muscle-specific promoters, we evaluated the expression and function of SRF in subconfluent and long term serum-deprived cells. Whole cell SRF mRNA and protein were maintained at high levels in serum-deprived myocytes, but SRF transcription-promoting activity, nuclear SRF binding to consensus CArG sequences, and nuclear SRF protein were reduced. Furthermore, immunocytochemistry revealed extranuclear redistribution of SRF in serum-deprived myocytes; nuclear localization of SRF was restored after serum refeeding. These results uncover a novel mechanism for physiological control of smooth muscle-specific gene expression through extranuclear redistribution of SRF and consequent down-regulation of its transcription-promoting activity.

Paclitaxel sensitivity of breast cancer cells with constitutively active NF-kappaB is enhanced by IkappaBalpha super-repressor and parthenolide

The transcription factor nuclear factor-kappaB (NF-kappaB) regulates genes important for tumor invasion, metastasis and chemoresistance. Normally, NF-kappaB remains sequestered in an inactive state by cytoplasmic inhibitor-of-kappaB (IkappaB) proteins. NF-kappaB translocates to nucleus and activates gene expression upon exposure of cells to growth factors and cytokines. We and others have shown previously that NF-kappaB is constitutively active in a subset of breast cancers. In this study, we show that constitutive activation of NF-kappaB leads to overexpression of the anti-apoptotic genes c-inhibitor of apoptosis 2 (c-IAP2) and manganese superoxide dismutase (Mn-SOD) in breast cancer cells. Furthermore, expression of the anti-apoptotic tumor necrosis factor receptor associated factor 1 (TRAF1) and defender-against cell death (DAD-1) is regulated by NF-kappaB in certain breast cancer cells. We also demonstrate that NF-kappaB-inducible genes protect cancer cells against paclitaxel as MDA-MB-231 breast cancer cells modified to overexpress IkappaBalpha required lower concentrations of paclitaxel to arrest at the G2/M phase of the cell cycle and undergo apoptosis when compared to parental cells. The effect of NF-kappaB on paclitaxel-sensitivity appears to be specific to cancer cells because normal fibroblasts derived from embryos lacking p65 subunit of NF-kappaB and wild type littermate embryos were insensitive to paclitaxel-induced G2/M cell cycle arrest. Parthenolide, an active ingredient of herbal remedies such as feverfew (tanacetum parthenium), mimicked the effects of IkappaBalpha by inhibiting NF-kappaB DNA binding activity and Mn-SOD expression, and increasing paclitaxel-induced apoptosis of breast cancer cells. These results suggest that active ingredients of herbs with anti-inflammatory properties may be useful in increasing the sensitivity of cancers with constitutively active NF-kappaB to chemotherapeutic drugs. Oncogene (2000) 19, 4159 - 4169

Surgical management of localized amyloidosis

OBJECTIVE

To demonstrate the role of two-dimensional reconstruction images on computed tomography (CT) in the treatment planning for laryngeal amyloidosis. To discuss the treatment for isolated laryngeal amyloidosis and compare the role of endoscopic versus an open surgical approach to management.

STUDY DESIGN

Retrospective review.

METHODS

The medical records from 1984 to the present with the diagnosis of localized respiratory tract amyloidosis at Geisinger Medical Center were reviewed.

RESULTS

Five previously unpublished cases of localized laryngeal amyloidosis were identified with the supraglottic region the major site of involvement. Hoarseness and airway compromise were the presenting symptoms. CT two-dimensional reconstruction imaging was used to evaluate two cases with extensive laryngeal involvement that required an external surgical approach to relieve symptoms.

CONCLUSIONS

Localized laryngeal amyloidosis is a rare disease that requires surgical management when symptomatic. CT two-dimensional reconstruction can be helpful in detailing the extent of disease and planning surgery. A lateral external supraglottic approach has been found to be successful in treating patients with large supraglottic masses.

The orphan receptor COUP-TFII regulates G2/M progression of breast cancer cells by modulating the expression/activity of p21(WAF1/CIP1), cyclin D1, and cdk2

The orphan receptors COUP-TFI and COUP-TFII play an important role in development and differentiation by activating specific genes and by modulating the activity of nuclear receptors including estrogen receptor alpha (ERalpha) and retinoic acid receptors (RARs). Previously, it was demonstrated that the expression and activity of ERalpha and RARs are lost or impaired in anti-estrogen-resistant breast cancers. Here we show that, similar to ERalpha and RARs, the expression of COUP-TFII but not COUP-TFI is reduced in approximately 30% of breast cancer cell lines. Introduction of COUP-TFII to MDA-MB-435 cells resulted in reduced growth and plating efficiency. Interestingly, COUP-TFII increased the expression of cyclin D1 and p21(WAF1/CIP1) in MDA-MB-435 cells. Although parental and COUP-TFII-transduced cells progressed through the G1-S phase at a similar rate, progression of COUP-TFII cells through the G2/M transition phase was delayed. The activity of cdk2 required for G2/M progression was reduced in COUP-TFII cells compared to parental cells. This property of COUP-TFII is distinct from that of ERalpha and RARs, which usually modulate the G1 phase of breast cancer cells. Furthermore, these results reveal an important physiological function of COUP-TFII, which correlates with its ability to induce gene expression rather than modulation of nuclear receptor activity.

Negative regulation of transactivation function but not DNA binding of NF-kappaB and AP-1 by IkappaBbeta1 in breast cancer cells

The transcription factor NF-kappaB regulates the expression of genes involved in cancer cell invasion, metastasis, angiogenesis, and resistance to chemotherapy. In normal cells NF-kappaB is maintained in the cytoplasm by protein-protein interaction with inhibitor IkappaBs. In contrast, in cancer cells a substantial amount of NF-kappaB is in the nucleus and constitutively activates target genes. To understand the mechanisms of constitutive NF-kappaB activation, we have analyzed the function of IkappaBalpha and IkappaBbeta in breast cancer cells. In most cases, constitutive NF-kappaB DNA binding correlated with reduced levels of either IkappaBalpha or IkappaBbeta isoforms. Overexpression of IkappaBalpha but not IkappaBbeta1 resulted in reduced constitutive DNA binding of NF-kappaB in MDA-MB-231 cells. Unexpectedly, IkappaBbeta1 overexpression moderately increased 12-O-tetradecanoylphorbol-13-acetate- and interleukin-1-inducible NF-kappaB DNA binding. 12-O-Tetradecanoylphorbol-13-acetate- and interleukin-1-induced transactivation by NF-kappaB, however, was lower in IkappaBbeta1-overexpressing cells. Mutants of IkappaBbeta1 lacking the C-terminal casein kinase II phosphorylation sites, which form a stable complex with DNA bound NF-kappaB without inhibiting its transactivation in other cell types, repressed the transactivation by NF-kappaB in MDA-MB-231 cells. Consistent with the results of transient transfections, the expression of urokinase plasminogen activator, an NF-kappaB target gene, was reduced in IkappaBbeta1-overexpressing cells. These results suggest that depending on the cell type, IkappaBbeta1 represses the expression of NF-kappaB-regulated genes by inhibiting either DNA binding or transactivation function of NF-kappaB.

Use of a rapid intraoperative parathyroid hormone assay in the surgical management of parathyroid disease

OBJECTIVE

To evaluate the utility of a rapid intraoperative parathyroid hormone (PTH) immunoradiometric assay in the surgical management of parathyroid disease, particularly with reference to limiting extent of cervical exploration.

DESIGN

Nonrandomized prospective study.

SETTING

Academic tertiary care center.

PATIENTS

Forty-three consecutive patients undergoing parathyroid exploration for adenoma or hyperplasia had rapid PTH assays performed from blood drawn at induction and 7 minutes after resection of all hyperfunctioning parathyroid tissue.

OUTCOME MEASURES

Excision of all hyperfunctioning parathyroid tissue as assessed by bilateral neck exploration, postoperative normalization of serum calcium and PTH levels, and resolution of clinical symptoms.

RESULTS

The intraoperative rapid PTH assay accurately reflected whether all hyperfunctioning parathyroid tissue was excised in every patient. In 41 patients, all hyperfunctioning parathyroid tissue was resected at the time of surgery and confirmed by a corresponding decrease in the intraoperative postexcision rapid PTH determination as well as by subsequent normalization of postoperative serum calcium and PTH levels and resolution of clinical symptoms. In 2 patients, the postexcision rapid PTH assay determination was not consistent with removal of all hyperfunctioning parathyroid disease and both patients demonstrated persistent hyperparathyroidism postoperatively.

CONCLUSIONS

The intraoperative rapid PTH assay may be of significant benefit in permitting directed unilateral parathyroid explorations for adenoma when combined with preoperative localization with a technetium-99m sestamibi scan. Additionally, the rapid PTH assay has proved to be of benefit in confirming excision of all hyperfunctioning parathyroid tissue in patients with multiple gland hyperplasia, particularly those who may harbor ectopic parathyroid tissue.

Novel HIV-protease inhibitors containing beta-hydroxyether and -thioether dipeptide isostere surrogates: modification of the P3 ligand

Studies involving modifications to the P3 position of previously described HIV-protease inhibitors containing beta-hydroxyether and thioether dipeptide isostere replacements led to the discovery of pseudopeptides 8o and 8p with improved antiviral activities.

The synthesis of novel HIV-protease inhibitors

The syntheses, enzyme inhibition and antiviral activity of potent HIV-protease inhibitors containing novel beta-hydroxy ether and thioethers based on the transition state mimetic concept are discussed.

In vitro buffering capacity of residual peritoneal dialysate fluid: implications for peritoneal dialysis therapy

The buffering capacity of the residual peritoneal dialysate fluid from each of 5 patients undergoing continuous ambulatory peritoneal dialysis was assessed by titrating with fresh, conventional, acidic, and lactate-containing peritoneal dialysis solutions. It was found that residual fluids had considerable buffering capacity.

The effects of shear stress on endothelial cell retention and function on expanded polytetrafluoroethylene

We evaluated the adherence of indium 111-radiolabeled endothelial cells to fibronectin-treated expanded polytetrafluoroethylene surfaces exposed to high (437 s-1) vs low (218 s-1) shear and the influence of shear on prostacyclin production. Canine jugular vein factor VIII-positive endothelial cells in passages 3 through 6 were incubated with 111Indium-oxine, and labeled cells were seeded onto fibronectin-treated expanded polytetrafluoroethylene patches. Patches with confluent cells were exposed to shear in a Weissenberg rheogoniometer for intervals ranging up to 60 minutes. Percent endothelial cell retention was determined by gamma counting of patches and media and by histologic evaluation. Prostacyclin production (tritiated radioimmunoassay of 6-keto-prostaglandin F1 alpha) was assayed on perfusing media. Results showed no differences in 6-keto-prostaglandin F1 alpha production between shear rates or time periods. Endothelial cell retention did not differ between the shear rates. Rotational shear caused persistent cell loss over time in either high- or low-shear conditions. This persistent cell loss in response to steady rotational shear differs from that in response to identical rates of pulsatile linear shear in our laboratory where cell loss approached zero after 15 minutes.

Comparative evaluation of an immunofluorescent antibody test, enzyme immunoassay and western blot for the detection of HIV-1 antibody

Screening blood and blood products for human immunodeficiency virus type 1 (HIV-1) antibody is predominantly performed by enzyme immunoassay (EIA), and results must be confirmed by the more immunospecific Western blot (WB) assay. This study evaluated an HIV immunofluorescent antibody (IFA) test relative to WB assay for use in confirming EIA designated HIV-1 antibody-positive sera. Specimens from seroconversion and CDC panels as well as clinical specimens obtained for routine EIA HIV-1 antibody screening were evaluated. Results with 209 specimens indicated that sensitivity and specificity of the Fluorognost-HIV assay were equivalent relative to WB. In addition, the Fluorognost-HIV IFA test was faster and easier to perform than the WB assay, and unlike the WB assay was not prone to indeterminate results.

An in vitro slice preparation of the cat lateral geniculate nucleus

A slice preparation of the cat thalamus containing the lateral geniculate nucleus and the terminal portion of the optic tract is described. Ultrastructurally the slices remain relatively normal for only a short time after cutting. Indeed most cellular elements deteriorate quickly with time but patches of relatively intact tissue were still present even 10 h after cutting and maintenance in a storage bath. However, for 4-5 h after cutting long-lasting intracellular recordings of high quality and stability were obtained, and intrasomatic injection of horseradish peroxidase used for the morphological identification of recorded neurones as X or Y cells.