Natural bond orbital, nuclear magnetic resonance analysis and hybrid-density functional theory study of σ-aromaticity in Al2F6, Al2Cl6, Al2Br6 and Al2I6

Natural bond orbital (NBO), nuclear magnetic resonance (NMR) analysis and hybrid-density functional theory based method (B3LYP/Def2-TZVPP) were used to investigate the correlation between the nucleus-independent chemical shifts [NICS, as an aromaticity criterion], σ _Al(1)-X2(b) → σ*_Al(3)-X4(b) electron delocalizations and the dissociation energies of Al₂F₆, Al₂Cl₆, Al₂Br₆ and Al₂I₆ to 2AlX₃ (X?=?F, Cl, Br, I). The results obtained showed that the dissociation energies of Al₂F₆, Al₂Cl₆, Al₂Br₆ and Al₂I₆ decrease from Al₂F₆ to Al₂I₆. Like aromatic molecules, these compounds have relatively significant negative NICS_iso(0) values. Clearly, based on magnetic criteria, they exhibit aromatic character and make it possible to consider them as σ-delocalized aromatic species, such as Möbius σ-aromatic species. The σ-aromatic character which is demonstrated by their NICS_iso(0) values decreases from Al₂F₆ to Al₂I₆. The NICS_iso values are dominated by the in-plane σ₂₂ (i.e., σ_yy, the plane containing halogen atoms bridged) chemical shift components. The increase of the NICS_iso values explains significantly the decrease of the corresponding dissociation energies of Al₂F₆, Al₂Cl₆, Al₂Br₆ and Al₂I₆. Importantly, the NBO results suggest that in these compounds the dissociation energies are controlled by the stabilization energies associated with σ _Al(1)-X2(b) →σ*_Al(3)-X4(b) electron delocalizations. The decrease of the stabilization energies associated with σ _Al(1)-X2(b) →σ*_Al(3)-X4(b) electron delocalizations is in accordance with the variation of the calculated NICS_iso values. The correlations between the dissociation energies of Al₂F₆, Al₂Cl₆, Al₂Br₆ and Al₂I₆, σ _Al(1)-X2(b) →σ*_Al(3)-X4(b) electron delocalizations, natural atomic orbitals (NAOs) and NICS_iso values have been investigated.     

Sex Specific Incidence Rates of Type 2 Diabetes and Its Risk Factors over 9 Years of Follow-Up: Tehran Lipid and Glucose Study

Objective

To investigate the population-based incidence of type 2 diabetes and its potential risk factors in a sex-split cohort of Iranian population.

Materials and Methods

A total of 8400 non-diabetic participants, aged ≥20 years (3620 men and 4780 women) entered the study. Crude and age standardized incidence rates per 1000 person-years were calculated for whole population and each sex separately. Cox proportional hazard models were used to evaluate hazard ratios (HR) and 95% confidence intervals for all potential risk factors in both uni-variable and multivariable models.

Results

During a median follow-up of 9.5 years, 736 new cases of diabetes were identified, including 433 women and 303 men. The annual crude and age-standardized incidence rates (95% CI) of diabetes in the total population were 10.6 (9.92–11.4) and 9.94 (7.39–13.6) per 1000 person-years of follow-up and the corresponding sex specific rates were 10.2 (9.13–11.4) and 9.36 (5.84–14.92) in men and 11.0 (9.99–12.0) and 10.1 (7.24–13.9) in women, respectively. In the multivariable model, the risk for incident diabetes was significantly associated with fasting and 2 hour post challenge plasma glucose as well as family history of diabetes in both men and women. However, among women, only the contribution of wrist circumference to incident diabetes achieved statistical significance [HR: 1.16 (1.03–1.31)] with waist/height ratio being marginally significant [HR: 1.02 (0.99–1.04)]; while among men, only body mass index was a significant predictor [HR: 1.12 (1.02–1.22)]. Additionally, low education level conferred a higher risk for incident diabetes only among men [HR: 1.80 (1.23–2.36); P for interaction with sex = 0.003].

Conclusion

Overall, sex did not significantly modify the impact of risk factors associated with diabetes among Iranian adults; however, among modifiable risk factors, the independent role of lower education and general adiposity in men and central adiposity in women might require different preventive strategies.     

Prehypertension Tsunami: A Decade Follow-Up of an Iranian Adult Population

ObjectivePrehypertension is associated with cardiovascular disease (CVD). There is no study to examine the incidence and risk factors of prehypertension in a sex stratified setting. The aim of this study was to examine the effect modification of sex for different risk factors which predicts the progression from normotension to prehypertension in a Middle East population-based cohort, during a median follow-up of 9.2 years.MethodsA multivariate Cox analysis was performed among 1466 and 2131 Iranian men and women, respectively, who were free of prehypertension, hypertension, CVD and diabetes at baseline and free of incident hypertension without preceding prehypertension at follow-up. Incident prehypertension at follow-up was defined as systolic blood pressure (SBP) of 120–139 mmHg and/or diastolic blood pressure (DBP) of 80–89 mmHg.ResultsOverall, 1440 new cases of prehypertension were identified resulting in an incidence rate of 593/10000 person-years; the corresponding values for women and men were 489/10000 and 764/10000person-years, respectively. There were significant interactions between gender with age, DBP, waist-to-hip-ratio (WHpR) and estimated glomerular filtration rate (eGFR) (all P-values <0.05) in multivariate analysis. Strong associations were found between age, body mass index (BMI) and SBP with incident prehypertension in both genders. However, the effect of DBP and WHpR was significant among women and 2-hour post challenge plasma glucose (2h-PCPG)was an independent risk factor for men. In the sex-adjusted analysis, glomerular hyperfiltration [Hazard ratio (HR) and 95%CI: 1.01 (1.00–1.01), P-value = 0.02], age, BMI, WHpR, SBP and DBP had higher risks while being female [HR (95%CI): 0.81(0.69–0.94), P-value = 0.01] had a lower risk for incident prehypertension.ConclusionAccording to this study results, among Iranian population with high incidence of prehypertension, general adiposity and glomerular hyperfiltration in total, 2h-PCPG in men and central adiposity in women should be emphasized as risk factors for prehypertension.     

Effect of Intravenous Sodium Valproate vs Dexamethasone on Acute Migraine Headache: A Double Blind Randomized Clinical Trial

Background

Despite the impact of sodium valproate and dexamethasone on migraine headache, the efficacy of the two drugs has not been properly investigated and compared. This trial compared the effect of the two drugs on acute migraine headache.

Methods

This double blind randomized clinical trial was conducted on patients aged 18 to 65 years with acute migraine headache who referred to the emergency departments of Beasat and Farshchian Hospitals in Hamadan, Iran, from April 2012 to June 2014. Patients were randomly assigned to receive a single-dose of either 400 mg sodium valproate or 16 mg dexamethasone plus 50 ml saline normal solution within 15 min intravenously. The severity of headache in the two groups was evaluated at baseline, 0.5 and 2 hours later using the Visual Analog Scale (VAS) on a scale of 0 to 10.

Results

Of 104 patients enrolled, 72 patients remained for analysis. The effect of both sodium valproate and dexamethasone on acute migraine headache was statistically significant at 0.5 and 2 hours post-treatment compared to pre-treatment (P=0.001). The severity of headache based on VAS reduced form 8.20 (7.72, 8.68) before treatment to 5.31 (4.74, 5.89) and 3.66 (2.99, 4.33) at 0.5 and 2 hours after treatment, respectively, in patients receiving sodium valproate and from 8.46 (8.05, 8.86) before treatment to 5.46 (4.81, 6.11) and 3.59 (2.84, 4.35) at 0.5 and 2 hours after treatment, respectively, in patients receiving dexamethasone. Both drugs were highly effective in improvement of acute headache in patients without aura. However, sodium valproate significantly improved the acute headache in patients with aura but dexamethasone did not. The severity of headache based on VAS reduced form 8.50 (7.40, 9.60) before treatment to 4.67 (2.40, 6.93) and 3.50 (1.78, 5.22) at 0.5 and 2 hours after treatment, respectively, in patients with aura receiving sodium valproate and from 8.80 (7.76, 9.84) before treatment to 7.20 (4.98, 9.42) and 6.20 (2.43, 9.97) at 0.5 and 2 hours after treatment, respectively, in patients with aura receiving dexamethasone.

Conclusions

This trial indicated that, in overall, intravenous sodium valproate is not superior to intravenous dexamethasone in treatment of acute migraine attacks. However, in patients with aura, only sodium valproate but not dexamethasone is effective in headache relief. This issue needs further investigations.

Trial Registration

ClinicalTrials.gov IRCT201202199014N1     

Protective effects of Withania somnifera root on inflammatory markers and insulin resistance in fructose-fed rats

Background:

We investigated the effects of Withania somnifera root (WS) on insulin resistance, tumor necrosis factor α (TNF-α), and interleukin-6 (IL-6) in fructose-fed rats.

Methods:

Forty-eight Wistar-Albino male rats were randomly divided into four groups (n=12); Group I as control, Group II as sham-treated with WS by 62.5mg/g per diet, Group III fructose-fed rats received 10%W/V fructose, and Group IV fructose- and WS-fed rats. After eight weeks blood samples were collected to measure glucose, insulin, IL-6, and TNF-α levels in sera.

Results:

Blood glucose, insulin, homeostasis model assessment for insulin resistance (HOMA-R), IL-6, and TNF-α levels were all significantly greater in the fructose-fed rats than in the controls. Treatment with WS significantly (P < 0.05) inhibited the fructose-induced increases in glucose, insulin, HOMA-R, IL-6, and TNF-α.

Conclusion:

Our data suggest that WS normalizes hyperglycemia in fructose-fed rats by reducing inflammatory markers and improving insulin sensitivity.Key Words: Withania somnifera, Insulin resistance, IL-6, TNF- α     

Abrogation of histone deacetylases (HDACs) decreases survival of chronic myeloid leukemia cells: New insight into attenuating effects of the PI3K/c-Myc axis on panobinostat cytotoxicity

Although the identification of tyrosine kinase inhibitors (TKIs) has changed the treatment paradigm of many cancer types including chronic myeloid leukemia (CML), still adjustment of neoplastic cells to cytotoxic effects of anticancer drugs is a serious challenge. In the area of drug resistance, epigenetic alterations are at the center of attention and the present study aimed to evaluate whether blockage of epigenetics mechanisms using a pan-histone deacetylase (HDAC) inhibitor induces cell death in CML-derived K562 cells. We found that the abrogation of HDACs using panobinostat resulted in a reduction in survival of the K562 cell line through p27-mediated cell cycle arrest. Noteworthy, the results of the synergistic experiments revealed that HDAC suppression could be recruited as a way to potentiate cytotoxicity of Imatinib and to enhance the therapeutic efficacy of CML. Here, we proposed for the first time that the inhibitory effect of panobinostat was overshadowed, at least partially, through the aberrant activation of the phosphoinositide 3-kinase (PI3K)/c-Myc axis. Meanwhile, we found that upon blockage of autophagy and the proteasome pathway, as the main axis involved in the activation of autophagy, the anti-leukemic property of the HDAC inhibitor was potentiated. Taken together, our study suggests the beneficial application of HDAC inhibition in the treatment strategies of CML; however, further in vivo studies are needed to determine the efficacy of this inhibitor, either as a single agent or in combination with small molecule inhibitors of PI3K and/or c-Myc in this malignancy.     

Gold or silver deposited on layered manganese oxide: a functional model for the water-oxidizing complex in photosystem II

In this report, gold or silver deposited on layered manganese oxide has been synthesized by a simple method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, atomic absorption spectroscopy, and energy-dispersive X-ray mapping. The gold deposited on layered manganese oxide showed efficient catalytic activity toward water oxidation in the presence of cerium(IV) ammonium nitrate. The properties associated with this compound suggest it is a functional model for the water-oxidizing complex in photosystem II.