Impact of Lymphopenia on Definitive Treatment of Locally Advanced Cervical Cancer

PURPOSE/OBJECTIVE(S)

Pre-treatment lymphopenia prior to initiating treatment has been correlated with reduced survival in a number of different cancers. The purpose of this study is to evaluate the association between lymphopenia and survival in women with locally advanced cervical cancer (LACC) treated with primary chemoradiation (CRT).

MATERIALS/METHODS

We retrospectively reviewed patients with LACC treated at a single institution from 2005 - 2021 with available lymphocyte information. Patient and treatment characteristics were recorded including age, tumor size and stage, EBRT dose/fractionation, and brachytherapy dosimetry data. Absolute lymphocyte counts (ALC) were collected prior to initiating CRT and at 3-month intervals following CRT and graded based on severity of lymphopenia using CTCAE v 5.0. Overall survival (OS), progression free survival (PFS), and local control (LC) were calculated from the start of treatment to date of last follow-up. Kaplan-Meier survival analysis was performed to evaluate whether lymphocyte changes were associated with OS, PFS, or LC.

RESULTS

A total of 124 patients met study inclusion criteria with stage IB - IV disease (41 stage I, 41 stage II, 36 stage III, 6 stage IV) and a median follow up of 3.6 years (range 0.2-16.5 years). The median age was 49 years (range 26-77). The median EBRT dose was 45 Gy (range: 26-57.5 Gy) and 44.2% of patients received para-aortic (PA) nodal EBRT (28.8% elective and 15.4% with positive PA nodes). 5-year OS, PFS, and LC were 60.3% (95% CI 51.5-70.7), 47.5% (95% CI 39-58), and 75.5% (95% CI 67.3-82.9), respectively. Pre-treatment lymphopenia (ALC <1000 cells/mm3) was present in 11 (9%) patients. When the total cohort was divided into patients with and without pre-treatment lymphopenia, OS was statistically improved in the patients without baseline lymphopenia, with a 5-year OS of 63.2% (95% CI 53.9-73.9) versus 35.3% (95% CI 14.5-86.3) in the lymphopenia group (p = 0.034). LC also trended to being improved in the patients without lymphopenia, though this did not reach statistical significance in our small sample size of lymphopenic patients, with 5-year LC of 76.8% (95% CI 68.4-84.3) versus 67.5% (05% CI 36.6-93.8), p = 0.45.

CONCLUSION

In this single institution experience of LACC treated with definitive CRT, we found that baseline lymphopenia is associated with inferior OS. Patients with higher pre-CRT ALC may represent a population with more robust immune systems, producing more favorable tumor responses to treatment. Additional studies are warranted to investigate the evolving role of combined EBRT and systemic therapy in LACC.

Molecular Dynamics and Free Energy Calculations of Dicyclohexano-18-crown-6 Diastereoisomers with Sm2+, Eu2+, Dy2+, Yb2+, Cf2+, and Three Halide Salts in Tetrahydrofuran and Acetonitrile Using the AMOEBA Force Field

With the continual development of lanthanides (Ln) in current technological devices, an efficient separation process is needed that can recover greater amounts of these rare elements. Dicyclohexano-18-crown-6 (DCH18C6) is a crown ether that may be a promising candidate for Ln separation, but additional research is required. As such, molecular dynamics (MD) simulations have been performed on four divalent lanthanide halide salts (Sm2+, Eu2+, Dy2+, and Yb2+) and one divalent actinide halide salt (Cf2+) bound to three diastereoisomers of DCH18C6. Dy2+, Yb2+, Cf2+, DCH18C6, and tetrahydrofuran (THF) solvent were parameterized for the AMOEBA polarizable force field for the first time, whereas existing parameters for Sm2+ and Eu2+ were utilized from our previous efforts. A coordination number (CN) of six for Ln2+/An2+-O solvated in THF indicated that the cations interacted almost entirely with the oxygens of the polyether ring. A CN of one for Ln2+/An2+-N solvated in acetonitrile for systems containing iodide suggested that the N atom of acetonitrile was competitive with I- for cation interactions. Fluctuation between five and six CNs for Dy2+ and Yb2+ suggested that although the cations remained in the polyether ring, the size of the ring may not be an ideal fit as these cations possess comparatively smaller ionic radii. Gibbs binding free energies of Sm2+ in all DCH18C6 diastereoisomers solvated in THF were calculated. The binding free energy of the cis-syn-cis diastereoisomer was the most favorable, followed by cis-anti-cis, and then trans-anti-trans. Finally, two major types of conformation were observed for each diastereoisomer that were related to the electrostatic interactions and charge density of the cations.

Automation of AMOEBA polarizable force field for small molecules: Poltype 2

A next-generation protocol (Poltype 2) has been developed which automatically generates AMOEBA polarizable force field parameters for small molecules. Both features and computational efficiency have been drastically improved. Notable advances include improved database transferability using SMILES, robust torsion fitting, non-aromatic ring torsion parameterization, coupled torsion-torsion parameterization, Van der Waals parameter refinement using ab initio dimer data and an intelligent fragmentation scheme that produces parameters with dramatically reduced ab initio computational cost. Additional improvements include better local frame assignment for atomic multipoles, automated formal charge assignment, Zwitterion detection, smart memory resource defaults, parallelized fragment job submission, incorporation of Psi4 quantum package, ab initio error handling, ionization state enumeration, hydration free energy prediction and binding free energy prediction. For validation, we have applied Poltype 2 to ~1000 FDA approved drug molecules from DrugBank. The ab initio molecular dipole moments and electrostatic potential values were compared with Poltype 2 derived AMOEBA counterparts. Parameters were further substantiated by calculating hydration free energy (HFE) on 40 small organic molecules and were compared with experimental data, resulting in an RMSE error of 0.59 kcal/mol. The torsion database has expanded to include 3543 fragments derived from FDA approved drugs. Poltype 2 provides a convenient utility for applications including binding free energy prediction for computational drug discovery. Further improvement will focus on automated parameter refinement by experimental liquid properties, expansion of the Van der Waals parameter database and automated parametrization of modified bio-fragments such as amino and nucleic acids.

Recent progress in general force fields of small molecules

Recent advances in computational hardware and free energy algorithms enable a broader application of molecular simulation of binding interactions between receptors and small-molecule ligands. The underlying molecular mechanics force fields (FFs) for small molecules have also achieved advancements in accuracy, user-friendliness, and speed during the past several years (2018-2020). Besides the expansion of chemical space coverage of ligand-like molecules among major popular classical additive FFs and polarizable FFs, new charge models have been proposed for better accuracy and transferability, new chemical perception of avoiding predefined atom types have been applied, and new automated parameterization toolkits, including machine learning approaches, have been developed for users' convenience.

Molecular dynamics free energy simulations of ATP:Mg2+ and ADP:Mg2+ using the polarizable force field AMOEBA

ATPases and GTPases are two important classes of protein that play critical roles in energy transduction, cellular signaling, gene regulation and catalysis. These proteins use cofactors such as nucleoside di and tri-phosphates (NTP, NDP) and can detect the difference between NDP and NTP which then induce different protein conformations. Mechanisms that drive proteins into the NTP or NDP conformation may depend on factors such as ligand structure and how Mg²⁺ coordinates with the ligand, amino acids in the pocket and water molecules. Here, we have used the advanced electrostatic and polarizable force field AMOEBA and molecular dynamics free energy simulations (MDFE) to examine the various binding mechanisms of ATP:Mg²⁺ and ADP:Mg²⁺.We compared the ATP:Mg²⁺ binding with previous studies using non-polarizable force fields and experimental data on the binding affinity. It was found that the total free energy of binding for ATP:Mg²⁺ (-7.00 ± 2.13 kcal/mol) is in good agreement with experimental values (-8.6 ± .2 kcal/mol)¹. In addition, parameters for relevant protonation states of ATP, ADP, GTP and GDP have been derived. These parameters will allow for researchers to investigate biochemical phenomena involving NTP's and NDP's with greater accuracy than previous studies involving non-polarizable force fields.

Can Cost-effectiveness Analysis Inform Genotype-Guided Aspirin Use for Primary Colorectal Cancer Prevention?

BACKGROUND

Inherited genetic variants can modify the cancer-chemopreventive effect of aspirin. We evaluated the clinical and economic value of genotype-guided aspirin use for colorectal cancer chemoprevention in average-risk individuals.

METHODS

A decision analytical model compared genotype-guided aspirin use versus no genetic testing, no aspirin. The model simulated 100,000 adults ≥50 years of age with average colorectal cancer and cardiovascular disease risk. Low-dose aspirin daily starting at age 50 years was recommended only for those with a genetic test result indicating a greater reduction in colorectal cancer risk with aspirin use. The primary outcomes were quality-adjusted life-years (QALY), costs, and incremental cost-effectiveness ratio (ICER).

RESULTS

The mean cost of using genotype-guided aspirin was $187,109 with 19.922 mean QALYs compared with $186,464 with 19.912 QALYs for no genetic testing, no aspirin. Genotype-guided aspirin yielded an ICER of $66,243 per QALY gained, and was cost-effective in 58% of simulations at the $100,000 willingness-to-pay threshold. Genotype-guided aspirin was associated with 1,461 fewer polyps developed, 510 fewer colorectal cancer cases, and 181 fewer colorectal cancer-related deaths. This strategy prevented 1,078 myocardial infarctions with 1,430 gastrointestinal bleeding events, and 323 intracranial hemorrhage cases compared with no genetic testing, no aspirin.

CONCLUSIONS

Genotype-guided aspirin use for colorectal cancer chemoprevention may offer a cost-effective approach for the future management of average-risk individuals.

IMPACT

A genotype-guided aspirin strategy may prevent colorectal cancer, colorectal cancer-related deaths, and myocardial infarctions, while minimizing bleeding adverse events. This model establishes a framework for genetically-guided aspirin use for targeted chemoprevention of colorectal cancer with application toward commercial testing in this population.

Innovation and enculturation in child communication: a cross-sectional study

How can people achieve successful communication when using novel signs? Previous studies show that iconic signs (i.e. signs that directly resemble their referent) enhance communication success. In this paper, we test if enculturated signs (i.e. signs informed by interlocutors' shared culture) also enhance communication success. Children, who have spent less time in their linguistic community, have less cultural knowledge to inform their sign innovation. A natural prediction is that younger children's signs will be less enculturated, more diverse and less successful compared with older children and adults. We examined sign innovation in children aged between 6 and 12 years (N = 54) and adults (N = 18). Sign enculturation, diversity and iconicity were rated. As predicted, younger children innovated less enculturated and more diverse signs, and communicated less successfully than older children and adults. Sign enculturation and iconicity uniquely contributed to communication success. This is the first study to demonstrate that enculturated signs enhance communication.

Adult Asthma Diagnosis: Physician Reported Challenges in Alberta-Based Primary Care Practices

Introduction

An estimated 8.1% of Canadians adults have asthma. While there are challenges associated with the use of objective measurement of lung function in the diagnosis of asthma, we are uncertain of the barriers that impact the use of objective measures, and have limited understanding of the challenges experienced by primary care providers in diagnosis of asthma. The objectives of this quality improvement initiative were to identify primary care providers’ methods of diagnosing asthma and to identify challenges with diagnosis.

Methods

An online survey was disseminated using a snowball methodology.

Setting

Primary care practices in Alberta, Canada.

Participants

A total of 84 primary care providers completed the survey.

Main Outcome Measures

Participants were asked their ideal and sufficient methods for diagnosing asthma and to identify challenges in their practice related to asthma diagnosis.

Results

They identified full pulmonary function testing (54%), pre- and postbronchodilator spirometry (54%), complete history and physical (42%), peak flow measurement overtime (26%), pulmonary consult (26%), and trial of asthma medication(s) (23%), as ideal methods of diagnosing asthma. The most significant barriers to diagnosis included episodic care–care provided typically during times of worsening symptoms without ongoing preventative/maintenance care (55%), patient follow-up (44%), conflict between clinical impression and pulmonary function results (43%), patient already on asthma medications (43%), and interpreting spirometry/pulmonary function results (39%).

Conclusion

The results of this survey indicate that the majority of primary care providers would choose full pulmonary function testing or pre- and postbronchodilator spirometry as the ideal methods of diagnosing asthma. However, barriers related to the nature of asthma care, patient factors, and challenges with diagnostic testing create challenges. This study also highlights that primary care providers have adapted to challenges in leveraging objective measurement and may rely upon other methods for diagnosis such as trials of medications.

Computational and Experimental Studies of Inhibitor Design for Aldolase A

Glycolytic enzyme fructose-bisphosphate aldolase A is an emerging therapeutic target in cancer. Recently, we have solved the crystal structure of murine aldolase in complex with naphthalene-2,6-diyl bisphosphate (ND1) that served as a template of the design of bisphosphate-based inhibitors. In this work, a series of ND1 analogues containing difluoromethylene (-CF₂), methylene (-CH₂), or aldehyde substitutions were designed. All designed compounds were studied using molecular dynamics (MD) simulations with the AMOEBA force field. Both energetics and structural analyses have been done to understand the calculated binding free energies. The average distances between ligand and protein atoms for ND1 were very similar to those for the ND1 crystal structure, which indicates that our MD simulation is sampling the correct conformation well. CF₂ insertion lowers the binding free energy by 10-15 kcal/mol, while CF₂ substitution slightly increases the binding free energy, which matches the experimental measurement. In addition, we found that NDB with two CF₂ insertions, the strongest binder, is entropically driven, while others including NDA with one CF₂ insertion are all enthalpically driven. This work provides insights into the mechanisms underlying protein-phosphate binding and enhances the capability of applying computational and theoretical frameworks to model, predict, and design diagnostic strategies targeting cancer.

Computational insights into the binding of IN17 inhibitors to MELK

The protein kinase MELK is an important kinase in cell signaling and has shown to be a promising anti-cancer target. Recent work has resulted in a novel small molecule scaffold targeting MELK, IN17. However, there has been little structural information or physical understanding of MELK-IN17 interactions. Using Tinker-OpenMM on GPUs, we have performed free energy simulations on MELK binding with IN17 and 11 derivatives. This series of studies provides structural insights into how substitution on IN17 leads to differences in complex structure and binding thermodynamics. In addition, this study serves as an assessment of the current capabilities of the AMOEBA forcefield, accelerated by GPU computing, to serve as a molecular-dynamics-based free energy simulation platform for lead optimization.

Treatment, outcomes and costs of asthma exacerbations in Chilean children: a prospective multicenter observational study

OBJECTIVE

To describe potential regional variations in therapies for severe asthma exacerbations in Chilean children and estimate the associated health expenditures.

METHODS

Observational prospective cohort study in 14 hospitals over a one-year period. Children five years of age or older were eligible for inclusion. Days with oxygen supply and pharmacological treatments received were recorded from the clinical chart. A basic asthma hospitalization basket was defined in order to estimate the average hospitalization cost for a single patient. Six months after discharge, new visits to the Emergency Room (ER), use of systemic corticosteroids and adherence to the controller treatment were evaluated.

RESULTS

396 patients were enrolled. Patients from the public health system and from the north zone received significantly more days of oxygen, systemic corticosteroids and antibiotics. Great heterogeneity in antibiotic use among the participating hospitals was found, from 0 to 92.3% (ICC 0.34, 95% CI 0.16-0.52). The use of aminophylline, magnesium sulfate and ketamine varied from 0 to 36.4% between the different Pediatric Intensive Care Units (ICC 0.353, 95% CI 0.010-0.608). The average cost per inpatient was of $1910 USD. 290 patients (73.2%) completed the follow-up six months after discharge. 76 patients (26.2%) were not receiving any controller treatment and nearly a fourth had new ER visits and use of systemic corticosteroids due to new asthma exacerbations.

CONCLUSIONS

Considerable practice variation in asthma exacerbations treatment was found among the participating hospitals, highlighting the poor outcome of many patients after hospital discharge, with an important health cost.

Hospitalizations for asthma exacerbation in Chilean children: A multicenter observational study

BACKGROUND

Asthma hospitalization rates in Chilean children have increased in the last 14 years, but little is known about the factors associated with this.

OBJECTIVE

Describe clinical characteristics of children hospitalized for asthma exacerbation.

METHODS

Observational prospective cohort study in 14 hospitals. Over a one-year period, children five years of age or older hospitalized with asthma exacerbation were eligible for inclusion. Parents completed an online questionnaire with questions on demographic information, about asthma, indoor environmental contaminant exposure, comorbidities and beliefs about disease and treatment. Disease control was assessed by the Asthma Control Test. Inhalation technique was observed using a checklist.

RESULTS

396 patients were enrolled. 168 children did not have an established diagnosis of asthma. Only 188 used at least one controller treatment at the time of hospitalization. 208 parents said they believed their child had asthma only when they had an exacerbation and 97 correctly identified inhaled corticosteroids as anti-inflammatory treatment. 342 patients used the wrong spacer and 73 correctly performed all steps of the checklist.

CONCLUSIONS

Almost half of the patients were not diagnosed with asthma at the time of hospitalization despite having a medical history suggestive of the disease. In the remaining patients with an established diagnosis of asthma potentially modifiable factors like bad adherence to treatment and poor inhalation technique were found. Implementing a nationwide asthma program including continued medical education for the correct diagnosis and follow up of these patients and asthma education for patients and caregivers is needed to reduce asthma hospitalization rates in Chilean children.

Cost-effectiveness of genotype-guided aspirin use for colorectal cancer prevention

e18318

Background: Colonoscopy is the “gold standard” for colorectal cancer (CRC) screening. However, adherence rates are low and detection is not optimal. Concomitant aspirin chemoprevention is recommended by US Preventive Task Force, but bleeding complications can be limiting. Variant genotypes in aspirin metabolism can modify CRC and adenoma risk. Genotype guided aspirin (ggASA) use will identify a targeted average-risk population for maximal aspirin benefit while minimizing adverse events rates compared to the general population. We conducted a cost-effectiveness analysis (CEA) of primary chemoprevention in CRC using ggASA compared to no intervention, and colonoscopy ±general aspirin in healthy average-risk individuals. Methods: Our Markov decision analytical model consisted of 5 possible health states: no CRC/polyps, adenoma, pre-clinical CRC, CRC, and death. Model probabilities for CRC and its prevalence were estimated using SEER database and published literature. A microsimulation of 10,000 individuals aged 50-64 years was used to estimate cost-effectiveness from US payer perspective over lifetime. One way and probabilistic sensitivity analyses and model validation results will be reported in the final poster. Results: Our results suggest that compared to colonoscopy and no intervention, ggASA was associated with fewer CRC cases, and CRC-related deaths and MI cases. Compared to colonoscopy + general aspirin, ggASA was associated with fewer bleeding events, similar rates of CRC and CRC-related deaths, and fewer MI cases prevented. From a cost-effectiveness standpoint, ggASA use over a lifetime had the lowest costs and highest quality adjusted life years gained compared to other strategies, if testing costs were ignored. Once genetic testing costs exceeds $63, colonoscopy + general aspirin becomes the most cost effective strategy. Between genetic testing cost of $63-283, the costs of using ggASA per quality adjusted life year gained is below $100,000. Conclusions: Genotype-guided aspirin use precisely identifies an average-risk population, and lowers adverse events rates compared to general aspirin. The economic value of genotype-guided aspirin is dependent on the genetic testing costs.

A low-cost, do-it-yourself data-logging system to record animal activity in laboratory and small-enclosure experiments

With the increasing cost of prepackaged research equipment and restrictions on research budgets, there is a growing need for inexpensive solutions for data collection in laboratory and small enclosures across a range of research topics investigating responses of animals to experimental parameters. We present here a low-cost, modular passive infrared sensor and data-logging system for use in experiments evaluating animal activity and behaviour, easily assembled in a laboratory setting. This system comprises accessible kit-based components purchased from popular electronics suppliers. We present the hardware configuration, software coding, build of materials, circuit diagram and a sample dataset demonstrating that the system collects reliable data that is easily downloaded either through any terminal program, directly from the unit or via an SD card. It is hoped that this ‘freeware’ approach to activity-monitoring equipment will enable laboratory and enclosure-based research to be undertaken more cost-effectively.

Comparing hospital and telephone follow-up for patients treated for stage-I endometrial cancer (ENDCAT trial): a randomised, multicentre, non-inferiority trial

OBJECTIVE

To evaluate the effectiveness of nurse-led telephone follow-up (TFU) for patients with stage-I endometrial cancer.

DESIGN

Multicentre, randomised, non-inferiority trial.

SETTING

Five centres in the North West of England.

SAMPLE

A cohort of 259 women treated for stage-I endometrial cancer attending hospital outpatient clinics for routine follow-up.

METHODS

Participants were randomly allocated to receive traditional hospital based follow-up (HFU) or nurse-led TFU.

MAIN OUTCOME MEASURES

Primary outcomes were psychological morbidity (State Trait Anxiety Inventory, STAI-S) and patient satisfaction with the information provided. Secondary outcomes included patient satisfaction with service, quality of life, and time to detection of recurrence.

RESULTS

The STAI-S scores post-randomisation were similar between groups [mean (SD): TFU 33.0 (11.0); HFU 35.5 (13.0)]. The estimated between-group difference in STAI-S was 0.7 (95% confidence interval, 95% CI -1.9 to 3.3); the confidence interval lies above the non-inferiority limit (-3.5), indicating the non-inferiority of TFU. There was no significant difference between groups in reported satisfaction with information (odds ratio, OR 0.9; 95% CI 0.4-2.1; P = 0.83). Women in the HFU group were more likely to report being kept waiting for their appointment (P = 0.001), that they did not need any information (P = 0.003), and were less likely to report that the nurse knew about their particular case and situation (P = 0.005).

CONCLUSIONS

The TFU provides an effective alternative to HFU for patients with stage-I endometrial cancer, with no reported physical or psychological detriment. Patient satisfaction with information was high, with similar levels between groups.

TWEETABLE ABSTRACT

ENDCAT trial shows effectiveness of nurse-led telephone follow-up for patients with stage-I endometrial cancer.

Combinatorial release of dexamethasone and amiodarone from a nano-structured parylene-C film to reduce perioperative inflammation and atrial fibrillation

Suppressing perioperative inflammation and post-operative atrial fibrillation requires effective drug delivery platforms (DDP). Localized anti-inflammatory and anti-arrhythmic agent release may be more effective than intravenous treatment to improve patient outcomes. This study utilized a dexamethasone (DEX) and amiodarone (AMIO)-loaded Parylene-C (PPX) nano-structured film to inhibit inflammation and atrial fibrillation. The PPX film was tested in an established pericardial adhesion rabbit model. Following sternotomy, the anterior pericardium was resected and the epicardium was abraded. Rabbits were randomly assigned to five treatment groups: control, oxidized PPX (PPX-Oxd), PPX-Oxd infused with DEX (PPX-Oxd[DEX]), native PPX (PPX), and PPX infused with DEX and AMIO (PPX[AMIO, DEX]). 4 weeks post-sternotomy, pericardial adhesions were evaluated for gross adhesions using a 4-point grading system and histological evaluation for epicardial neotissue fibrosis (NTF). Atrial fibrillation duration and time per induction were measured. The PPX[AMIO, DEX] group had a significant reduction in mean adhesion score compared with the control group (control 2.75 ± 0.42 vs. PPX[AMIO, DEX] 0.25 ± 0.42, P < 0.001). The PPX[AMIO, DEX] group was similar to native PPX (PPX 0.38 ± 0.48 vs. PPX[AMIO, DEX] 0.25 ± 0.42, P=NS). PPX-Oxd group adhesions were indistinguishable from controls (PPX-Oxd 2.83 ± 0.41 vs. control 2.75 ± 0.42, P=NS). NTF was reduced in the PPX[AMIO, DEX] group (0.80 ± 0.10 mm) compared to control (1.78 ± 0.13 mm, P < 0.001). Total duration of atrial fibrillation was decreased in rabbits with PPX[AMIO, DEX] films compared to control (9.5 ± 6.8 s vs. 187.6 ± 174.7 s, p = 0.003). Time of atrial fibrillation per successful induction decreased among PPX[AMIO, DEX] films compared to control (2.8 ± 1.2 s vs. 103.2 ± 178 s, p = 0.004). DEX/AMIO-loaded PPX films are associated with reduced perioperative inflammation and a diminished atrial fibrillation duration. Epicardial application of AMIO, DEX films is a promising strategy to prevent post-operative cardiac complications.

The hydrochloride and hydrobromide salt forms of (S)-amphetamine

Despite the high profile of amphetamine, there have been relatively few structural studies of its salt forms. The lack of any halide salt forms is surprising as the typical synthetic route for amphetamine initially produces the chloride salt. (S)-Amphetamine hydrochloride [systematic name: (2S)-1-phenylpropan-2-aminium chloride], C9H14N(+)·Cl(-), has a Z' = 6 structure with six independent cation-anion pairs. That these are indeed crystallographically independent is supported by different packing orientations of the cations and by the observation of a wide range of cation conformations generated by rotation about the phenyl-CH2 bond. The supramolecular contacts about the anions also differ, such that both a wide variation in the geometry of the three N-H...Cl hydrogen bonds formed by each chloride anion and differences in C-H...Cl contacts are apparent. (S)-Amphetamine hydrobromide [systematic name: (2S)-1-phenylpropan-2-aminium bromide], C9H14N(+)·Br(-), is broadly similar to the hydrochloride in terms of cation conformation, the existence of three N-H...X hydrogen-bond contacts per anion and the overall two-dimensional hydrogen-bonded sheet motif. However, only the chloride structure features organic bilayers and Z' > 1.

Impact of the serum- and glucocorticoid-inducible kinase 1 on platelet dense granule biogenesis and secretion

BACKGROUND

Platelet secretion is critical to development of acute thrombotic occlusion. Platelet dense granules contain a variety of important hemostatically active substances. Nevertheless, biogenesis of platelet granules is poorly understood.

OBJECTIVES

Serum- and glucocorticoid-inducible kinase 1 (SGK1) has been shown to be highly expressed in platelets and megakaryocytes, but its role in the regulation of platelet granule biogenesis and its impact on thrombosis has not been investigated so far.

METHODS AND RESULTS

Electron microscopy analysis of the platelet ultrastructure revealed a significant reduction in the number and packing of dense granules in platelets lacking SGK1 (sgk1(-/-) ). In sgk1(-/-) platelets serotonin content was significantly reduced and activation-dependent secretion of ATP, serotonin and CD63 significantly impaired. In vivo adhesion after carotis ligation was significantly decreased in platelets lacking SGK1 and occlusive thrombus formation after FeCl3 -induced vascular injury was significantly diminished in sgk1(-/-) mice. Transcript levels and protein abundance of dense granule biogenesis regulating GTPase Rab27b were significantly reduced in sgk1(-/-) platelets without affecting Rab27b mRNA stability. In MEG-01 cells transfection with constitutively active (S422) (D) SGK1 but not with inactive (K127) (N) SGK1 significantly enhanced Rab27b mRNA levels. Sgk1(-/-) megakaryocytes show significantly reduced expression of Rab27b and serotonin/CD63 levels compared with sgk1(+/+) megakaryocytes. Proteome analysis identified nine further vesicular transport proteins regulated by SGK1, which may have an impact on impaired platelet granule biogenesis in sgk1(-/-) platelets independent of Rab27b.

CONCLUSIONS

The present observations identify SGK1 as a novel powerful regulator of platelet dense granule biogenesis, platelet secretion and thrombus formation. SGK1 is at least partially effective because it regulates transcription of Rab27b in megakaryocytes.

Eight salt forms of sulfadiazine

Proton transfer to the sulfa drug sulfadiazine [systematic name: 4-amino-N-(pyrimidin-2-yl)benzenesulfonamide] gave eight salt forms. These are the monohydrate and methanol hemisolvate forms of the chloride (2-{[(4-azaniumylphenyl)sulfonyl]azanidyl}pyrimidin-1-ium chloride monohydrate, C(10)H(11)N(4)O(2)S(+) · Cl(-) · H2O, (I), and 2-{[(4-azaniumylphenyl)sulfonyl]azanidyl}pyrimidin-1-ium chloride methanol hemisolvate, C(10)H(11)N(4)O(2)S(+) · Cl(-) · (0.5)CH(3)OH, (II)); a bromide monohydrate (2-{[(4-azaniumylphenyl)sulfonyl]azanidyl}pyrimidin-1-ium bromide monohydrate, C(10)H(11)N(4)O(2)S(+) · Br(-) · H2O, (III)), which has a disordered water channel; a species containing the unusual tetraiodide dianion [bis(2-{[(4-azaniumylphenyl)sulfonyl]azanidyl}pyrimidin-1-ium) tetraiodide, 2C(10)H(11)N(4)O(2)S(+) · I4(2-), (IV)], where the [I4](2-) ion is located at a crystallographic inversion centre; a tetrafluoroborate monohydrate (2-{[(4-azaniumylphenyl)sulfonyl]azanidyl}pyrimidin-1-ium tetrafluoroborate monohydrate, C(10)H(11)N(4)O(2)S(+) · BF(4)(-) · H2O, (V)); a nitrate (2-{[(4-azaniumylphenyl)sulfonyl]azanidyl}pyrimidin-1-ium nitrate, C(10)H(11)N(4)O(2)S(+) · NO(3)(-), (VI)); an ethanesulfonate {4-[(pyrimidin-2-yl)sulfamoyl]anilinium ethanesulfonate, C(10)H(11)N(4)O(2)S(+) · C(2)H(5)SO(3)(-), (VII)}; and a dihydrate of the 4-hydroxybenzenesulfonate {4-[(pyrimidin-2-yl)sulfamoyl]anilinium 4-hydroxybenzenesulfonate dihydrate, C(10)H(11)N(4)O(2)S(+) · HOC(6)H(4)SO(3)(-) · 2H2O, (VIII)}. All these structures feature alternate layers of cations and of anions where any solvent is associated with the anion layers. The two sulfonate salts are protonated at the aniline N atom and the amide N atom of sulfadiazine, a tautomeric form of the sulfadiazine cation that has not been crystallographically described before. All the other salt forms are instead protonated at the aniline group and on one N atom of the pyrimidine ring. Whilst all eight species are based upon hydrogen-bonded centrosymetric dimers with graph set R2(2)(8), the two sulfonate structures also differ in that these dimers do not link into one-dimensional chains of cations through NH3-to-SO2 hydrogen-bonding interactions, whilst the other six species do. The chloride methanol hemisolvate and the tetraiodide are isostructural and a packing analysis of the cation positions shows that the chloride monohydrate structure is also closely related to these.