Imaging analysis of collagen fiber networks in cusps of porcine aortic valves: effect of their local distribution and alignment on valve functionality

The cusps of native aortic valve (AV) are composed of collagen bundles embedded in soft tissue, creating a heterogenic tissue with asymmetric alignment in each cusp. This study compares native collagen fiber networks (CFNs) with a goal to better understand their influence on stress distribution and valve kinematics. Images of CFNs from five porcine tricuspid AVs are analyzed and fluid-structure interaction models are generated based on them. Although the valves had similar overall kinematics, the CFNs had distinctive influence on local mechanics. The regions with dilute CFN are more prone to damage since they are subjected to higher stress magnitudes.     

Novel pyrrolizines bearing 3,4,5-trimethoxyphenyl moiety: design,synthesis, molecular docking,and biological evaluation as potential multi-target cytotoxic agents

In the present study, two new series of pyrrolizines bearing 3,4,5-trimethoxyphenyl moiety were designed, synthesised, and evaluated for their cytotoxic activity. The benzamide derivatives 16a–e showed higher cytotoxicity than their corresponding Schiff bases 15a–e. Compounds 16a,b,d also inhibited the growth of MCF-7/ADR cells with IC₅₀ in the range of 0.52–6.26 μM. Interestingly, the new compounds were less cytotoxic against normal MRC-5 cells (IC₅₀=0.155–17.08 μM). Mechanistic studies revealed the ability of compounds 16a,b,d to inhibit tubulin polymerisation and multiple oncogenic kinases. Moreover, compounds 16a,b,d induced preG₁ and G₂/M cell cycle arrest and early apoptosis in MCF-7 cells. The molecular docking analyses of compounds 16a,b,d into the active site in tubulin, CDK-2, and EGFR proteins revealed higher binding affinities compared to the co-crystallised ligands. These preliminary results suggested that compounds 16a,b,d could serve as promising lead compounds for the future development of new potent anticancer agents.

Highlights

1. Two new series of pyrrolizines bearing 3,4,5-trimethoxyphenyl moieties were synthesized.
2. Compounds 16a,b,d displayed the highest cytotoxicity against the three cancer cell lines.
3. Kinase profiling test revealed inhibition of multiple oncogenic kinases by compounds 16a,b,d.
4. Compounds 16a,b,d exhibited weak to moderate inhibition of tubulin-polymerization.
5. Compounds 16a,b,d induced preG₁ and G₂/M cell cycle arrest and early apoptosis in MCF-7 cells.
6. Docking studies revealed high binding affinities for compounds 16a,b towards tubulin and CDK-2.

     

The polymerase chain reaction: an epidemiological tool to differentiate between two clusters of pathogenic Yersinia enterocolitica strains

A primer set designed to amplify the enterotoxin (yst) gene of pathogenic Yersinia enterocolitica strains generated two different electrophoretic profiles of the target sequence when a collection of strains of worldwide origin was screened. Serovars O:1,3; O:2a,3; O:3; O:5,27 and O:9, known as European strains, produced a 200-bp fragment that matched the size of the target sequence. However, serovars O:4,32; O:8; O:13a,13b; O:20 and O:21, known as American strains, generated two fragments of 1.4 and 1.6 kb. The amplified products of one American strain were sequenced and the presence of the yst gene was confirmed in both fragments. Thus, the potential of the polymerase chain reaction to be used as an epidemiological tool in differentiation between the two clusters of pathogenic strains of Y. enterocolitica could be demonstrated.     

Communities of culturable yeasts and yeast-like fungi in oligotrophic hypersaline coastal waters of the Arabian Gulf surrounding Qatar

This report is the first investigation of yeast biodiversity from the oligotrophic hypersaline coastal waters of the Arabian Gulf surrounding Qatar. Yeasts and yeast-like fungi, were cultured from seawater sampled at 13 coastal areas surrounding Qatar over a period of 2 years (December 2013–September 2015). Eight hundred and forty-two isolates belonging to 82 species representing two phyla viz., Ascomycota (23 genera) and Basidiomycota (16 genera) were identified by molecular sequencing. The results indicated that the coastal waters of the Qatari oligotrophic marine environment harbor a diverse pool of yeast species, most of which have been reported from terrestrial, clinical and aquatic sources in various parts of the world. Five species, i.e., Candida albicans, C. parapsilosis, C. tropicalis, Pichia kudriavzevii and Meyerozyma guilliermondii (n?=?252/842; 30% isolates) are known as major opportunistic human pathogens. Fifteen species belonging to nine genera (n?=?498/842; 59%) and 12 species belonging to seven genera (n?=?459/842; 55%) are hydrocarbon degrading yeast and pollution indicator yeast species, respectively. Ascomycetous yeasts were predominant (66.38%; 559/842) as compared to their basidiomycetous counterparts (33.6%; 283/842). The most isolated yeast genera were Candida (28%; 236/842) (e.g., C. aaseri, C. boidinii, C. glabrata, C. intermedia, C. oleophila, C. orthopsilosis, C. palmioleophila, C. parapsilosis, C. pseudointermedia, C. rugopelliculosa, C. sake, C. tropicalis and C. zeylanoides), Rhodotorula (12.7%; 107/842), Naganishia (8.4%; 71/842), Aureobasidium (7.4%; 62/842), Pichia (7.3%; 62/842), and Debaryomyces (6.4%; 54/842). A total of eleven yeast species ( n = 38) isolated in this study are reported for the first time from the marine environment. Chemical testing demonstrated that seven out of the 13 sites had levels of total petroleum hydrocarbons (TPH) ranging from 200 to 900 µg/L, whereas 6 sites showed higher TPH levels (>?1000–21000 µg/L). The results suggest that the yeast community structure and density are impacted by various physico-chemical factors, namely total organic carbon, dissolved organic carbon and sulphur.

     

Effect of shoulder stability exercises on hand grip strength in patients with shoulder impingement syndrome

Background: Shoulder impingement syndrome (SIS) is the second most common musculoskeletal condition that causes shoulder pain in the general population. Shoulder girdle muscle imbalance and posterior capsule tightness have been implicated as contributing factors.

Objective: The purpose of this study was to investigate the effect of shoulder stability exercises (SSEs) on hand grip strength in patients with unilateral SIS.

Methods: A total of 16 patients with a mean age of 32?±?9.3?years diagnosed with stage II unilateral SIS participated in this study. A standardized SSE programme was conducted in the clinic under the direct 1-to-1 supervision of a physical therapist thrice weekly for 4?weeks for a total of 12 sessions on the affected and non-affected shoulders. The effect of the SSE programme on isometric hand grip strength was analysed.

Results: A significant difference (p?=?.016) was observed in the hand grip strength of the affected shoulder side before and after the intervention, but no significant difference (p?=?1.0) was found in the hand grip strength of the non-affected shoulder side post-intervention.

Conclusion: The reduction in isometric hand grip strength of the affected shoulder side compared to that of the non-affected shoulder side in the same subject before the intervention shows that SIS significantly affects the hand grip strength of the affected side. SSEs significantly affect the isometric hand grip strength of SIS patients.