Tailoring supramolecular guest-host hydrogel viscoelasticity with covalent fibrinogen double networks.

Supramolecular chemistry has enabled the design of tunable biomaterials that mimic the dynamic and viscoelastic characteristics of the extracellular matrix. However, the noncovalent nature of supramolecular bonds renders them inherently weak, limiting their applicability to many biomedical applications. To address this, we formulated double network (DN) hydrogels through a combination of supramolecular and covalent networks to tailor hydrogel viscoelastic properties. Specifically, DN hydrogels were formed through the combination of supramolecular guest-host (GH) hyaluronic acid (HA) networks with covalent networks from the photocrosslinking of acrylated poly(ethylene glycol) modified fibrinogen (PEG-fibrinogen) and PEG diacrylate. DN hydrogels exhibited higher compressive moduli, increased failure stresses, and increased toughness when compared to purely covalent networks. While GH concentration had little influence on the compressive moduli across DN hydrogels, an increase in the GH concentration resulted in more viscous behavior of DN hydrogels. High viability of encapsulated bovine mesenchymal stromal cells (MSCs) was observed across groups with enhanced spreading and proliferation in DN hydrogels with increased GH concentration. This combination of supramolecular and covalent chemistries enables the formation of dynamic hydrogels with tunable properties that can be customized towards repair of viscoelastic tissues.

Effects of Atrial Fibrillation Cardioversion after Percutaneous Mitral Balloon Valvuloplasty on Echocardiographic Left and Right Atrial Functions.

Amongst patients with mitral stenosis (MS), the most common complication is AF.Our study aimed at evaluating the effect of AF cardioversion after Percutaneous Mitral Balloon Valvuloplasty (PMBV) on echocardiographic atrial functions. The study included 34 patients with MS and AF, presenting to Ain-shams University hospitals, who underwent successful PMBV then randomized into 2 different groups according to AF management strategy. Group-I patients (n=16) received DC cardioversion after amiodarone infusion (within 24 hours post-PMBV) in addition to anticoagulation. Group-II patients (n= 18) were kept on the rate control strategy for AF and anticoagulation. Atrial functions were evaluated by echocardiography before and 48-72 hours after PMBV. Both groups were homogenous regarding demographic, clinical and echocardiographic data before PMBV. Both groups showed significant improvement in MVA (Group-I: 0.953 ± 0.144cm2 to 2.26 ± 0.463cm2, p=0.000, Group-II: 0.942 ± 0.171cm2 to 1.95 ± 0.40cm2 , p=0.0000), left atrial emptying fraction (Group-I:16.11 ± 6.93% to 26.16 ± 5.51%, p=0.000 , Group-II: 18.49 ± 5.47% to 26.12 ± 7.68%, p=0.002), left atrial function index (Group-I: 4.48 ± 2.32 to 6.84 ± 3.35, p=0.001 , Group-II: 3.34 ± 1.42 to 7.80 ± 4.17, p=0.006) as well as estimated systolic pulmonary artery pressure (Group-I: 49.06 ± 13.86 to 38.25 ± 7.29, p=0.01 , Group-II: 53.44 ± 14.52 to 39.88 ± 10.67, p=0.003). For group-I patients, reduction in left atrial end-diastolic volume was significant (120.84 ± 32.82 mL to 95.31 ± 19.27mL, p=0.012) and TAPSE showed significant improvement (17.57± 4.96 to 21.08 ± 2.52,p=0.018). When percentage improvement in variables was compared between both groups, none of the indices used to evaluate atrial functions showed any significant difference between both groups. Atrial functions improve post-PMBV. No additional improvement in atrial functions occurs after cardioversion in patients who have already undergone PMBV, at least within 72-hours.

Subclinical LV Dysfunction Detection Using Speckle Tracking Echocardiography in Hypertensive Patients with Preserved LV Ejection Fraction.

BACKGROUND: Early detection of subclinical left ventricular (LV) systolic dysfunction in hypertensive patients is important for the prevention of progression of hypertensive heart disease. METHODS: We studied 60 hypertensive patients (age ranged from 21 to 49 years, the duration of hypertension ranged from 1 to 18 years) and 30 healthy controls, all had preserved left ventricular ejection fraction (LVEF), detected by two-dimensional speckle tracking echocardiography (2D-STE). RESULTS: There was no significant difference between the two groups regarding ejection fraction (EF) by Simpson's method. Systolic velocity was significantly higher in the control group, and global longitudinal strain was significantly higher in the control group compared with the hypertensive group. In the hypertensive group, 23 of 60 patients had less negative global longitudinal strain than -19.1, defined as reduced systolic function, which is detected by 2D-STE (subclinical systolic dysfunction), when compared with 3 of 30 control subjects. CONCLUSION: 2D-STE detected substantial impairment of LV systolic function in hypertensive patients with preserved LVEF, which identifies higher risk subgroups for earlier medical intervention.

Early changes in longitudinal deformation indices in young asymptomatic patients with type 1 diabetes mellitus: assessment by speckle-tracking echocardiography.

BACKGROUND: We explored early changes in regional left ventricular systolic and diastolic function assessed by speckle-tracking echocardiography (STE) in young asymptomatic patients with type 1 diabetes mellitus (DM), compared with healthy controls. METHODS: We enrolled 30 normotensive asymptomatic patients with type 1 DM, age ≤40 years, DM duration >5 years, and left ventricular ejection fraction ≥50%; and thirty matched controls. They underwent conventional echocardiography, and tissue Doppler imaging (TDI). Myocardial deformation indices were measured by STE. We measured global longitudinal systolic strain, global longitudinal systolic strain rate, and global longitudinal early diastolic strain rate, as an average of 18 myocardial segments. RESULTS: The mean age was 27.7±4.5 years, (41.7% males). The mean duration of diabetes was 14.3±5.8 years. The 2-D ejection fraction was lower in diabetic patients versus controls (P=0.03). The trans-mitral A peak was higher, and isovolumetric relaxation time longer in diabetics (P<0.05 for both). Both lateral and septal É values were lower, and E/É ratio higher in diabetics (P<0.05 for all). The global longitudinal systolic strain and strain rate were decreased in diabetics (-17.7±2.5% versus -21.2±1.7%, and -1.1±0.2 versus -1.3±0.2 s-1, P<0.001 and P=0.003, respectively). The global longitudinal early diastolic strain rate was comparable to controls (1.5±0.4 versus 1.6±0.3 s-1, respectively, P=0.33). CONCLUSIONS: In asymptomatic patients with type 1 DM, global longitudinal systolic function measured by STE was impaired versus controls; diastolic function was impaired by conventional echocardiography and TDI.

Toxical effect of Peganum harmala L. leaves on the cotton leaf worm, Spodoptera littoralis Boisd and its parasitoids Microplitis rufiventris Kok.

The leaf extract and its fractions of Peganum harmala L. have shown pronounced mortal effect, decreased percent pupation and adult emergence of the cotton leaf worm, Spodoptera littoralis Boisd. The third instar larvae fed for two days on treated leaves were more susceptible to plant extract and its ethyl acetate and chloroform fractions. The active lowest concentration (5%) of the leaf fractions of P. harmala showed significant effect on the percentage of emerged adult parasitoids, Microplitis rufiventris Kok. GC/MS analysis showed the major constituent in ethyl acetate fraction was (23S) ethylcholest-5-en-3 beta-ol (28.04%) while those of chloroform fraction were hydroxyfuranocoumarin (Bergaptol) (15.68%), piperidinone (12.08%), thymol (11.82%), phosphoric acid, tributyl ester (9.80%) and trimethyl-nonenol (9.66%). The medicinal plant P. harmala could be carefully applied in integrated pest management due to its strong effect on cotton leaf worm pest.

Relationship between systolic pulsed wave tissue Doppler parameters and both invasive and noninvasive reperfusion criteria in patients with acute anterior myocardial infarction undergoing primary percutaneous coronary intervention.

BACKGROUND: Despite normal flow in the infarct-related artery after primary percutaneous coronary intervention, patients may not achieve adequate perfusion at the tissue level. We examined the applicability of pulsed wave tissue Doppler (PTD) in detection of successful myocardial reperfusion. METHODS: In all, 24 patients with anterior infarction were enrolled. All patients underwent primary percutaneous coronary intervention. PTD was performed 2 days and 2 weeks after percutaneous coronary intervention, and recorded from 6 different locations at the mitral annular level. Peak systolic wave was determined and was related to various markers of reperfusion. RESULTS: Systolic PTD measurement in patients with myocardial blush grades 0 to 1 significantly deteriorated between second day and second week (6.5 +/- 1.1-5.3 +/- 1.1 for the anterior wall, and 6.2 +/- 1.3-5.3 +/- 1 for the anterior septum, P < .05 and P < .01, respectively). Systolic PTD parameters improved significantly in patients with myocardial blush grades 2 to 3 (6 +/- 1.5-7.2 +/- 2 for the anterior wall, and 5.4 +/- 1.1-7.1 +/- 1.6 for the anterior septum, P < .05 and P < .01, respectively). A significant relationship was observed between PTD and thrombolysis in myocardial infarction flow, S-T resolution, and creatine phosphokinase peaking. PTD recovery was highly sensitive and specific for the detection of left ventricular function recovery. CONCLUSION: We demonstrated a significant relationship between systolic PTD parameters and invasive and noninvasive markers of reperfusion. Larger studies are needed to confirm these results.