QSAR of clinically important EGFR mutant L858R/T790M pyridinylimidazole inhibitors

EGFR is a well‐established therapeutic target of clinical relevance in cancer. However, acquisition of secondary mutation (T790M) makes first‐generation inhibitors ineffective. Therefore, to circumvent the problem of resistance, new T790M/L858R (TMLR) double mutant inhibitors are required. In this study, fragment‐based QSAR models (GQSAR) were generated for pyridinylimidazole derivatives having biological activity against TMLR mutants. The GQSAR model developed using partial least squares regression via stepwise forward–backward variable selection technique showed best results as judged using statistical parameters (r², q², and pred_r²). Additionally, applicability domain of the model was verified using Williams plot, which indicated that the predicted data are reliable. The GQSAR provided site‐specific clues wherein modifications related to decreasing lipophilic character and rotatable bonds and increasing SaaCHE‐index are required for improving inhibitory activity. Overall, the study indicated that the presence of acrylamide at R5 is essential for covalent bond formation with Cys797 and occurrence of aromatic residue at R2 is required for occupying hydrophobic region next to Met790 gatekeeper residue. Based on this information, new derivatives were designed that show better inhibitory activity than the experimentally reported most active molecules. Thus, the model developed can be used to design new pyridinylimidazole derivatives with improved TMLR bioactivity.     

Evaluating the Connect with Pharmacy web-based intervention to reduce hospital readmission for older people

International Journal of Clinical Pharmacy - Background The patient transition from a hospital to a post-discharge healthcare setting has potential to disrupt continuity of medication...     

DCE‐MRI findings of invasive aspergillosis in patient with acute myeloid leukemia

Thoracic radiography and high resolution computerized tomography is used to diagnose pulmonary infections in immunosuppressed patients, although in some cases these do not provide enough information about the lesion. Dynamic contrast‐enhanced magnetic resonance imaging may be useful in these cases, especially for the characterization of cavitary lesions and assessment of their contrast diffusion.     

Leptin signaling in adipose tissue: role in lipid accumulation and weight gain

Rationale: The link between obesity, hyperleptinemia, and development of cardiovascular disease is not completely understood. Increases in leptin have been shown to impair leptin signaling via caveolin-1-dependent mechanisms. However, the role of hyperleptinemia versus impaired leptin signaling in adipose tissue is not known. Objective: To determine the presence and significance of leptin-dependent increases in adipose tissue caveolin-1 expression in humans. Methods and Results: We designed a longitudinal study to investigate the effects of increases in leptin on adipose tissue caveolin-1 expression during weight gain in humans. Ten volunteers underwent 8 weeks of overfeeding, during which they gained an average weight of 4.1±1.4 kg, with leptin increases from 7±3.8 to 12±5.7 ng/mL. Weight gain also resulted in changes in adipose tissue caveolin-1 expression, which correlated with increases in leptin (rho=0.79, P=0.01). In cultured human white preadipocytes, leptin increased caveolin-1 expression, which in turn impaired leptin cellular signaling. Functionally, leptin decreased lipid accumulation in differentiating human white preadipocytes, which was prevented by caveolin-1 overexpression. Further, leptin decreased perilipin and fatty acid synthase expression, which play an important role in lipid storage and biogenesis. Conclusions: In healthy humans, increases in leptin, as seen with modest weight gain, may increase caveolin-1 expression in adipose tissue. Increased caveolin-1 expression in turn impairs leptin signaling and attenuates leptin-dependent lowering of intracellular lipid accumulation. Our study suggests a leptin-dependent feedback mechanism that may be essential to facilitate adipocyte lipid storage during weight gain.     

Muscle endothelial-dependent microvascular dysfunction in adulthood due to early postnatal overnutrition

The aims of our study were to investigate effects of postnatal overnutrition, obtained by restricting the number of pups per litter, on microcirculatory reactivity, fat depots, its total percentage and lipid profile. Microvascular reactivity was evaluated in the cremaster muscle of 24 hamsters divided into four groups, with 6 animals in each one: normal (NL) and restricted (RL) litter groups, both at 6th and 21st weeks of age. The NL group had 8-9 pups and the RL 3 pups per litter and to avoid the litter effect, only one animal was used per litter. The results have shown that the RL group had higher velocity of weight, body mass and fat gain compared to the NL one at weeks 6 and 21. Significant differences were also observed on urogenital fat depot, total cholesterol and low density lipoprotein between groups. At the lowest concentration of Ach, the RL group showed smaller arteriolar dilatation at the 21st than at the 6th week [5(3-13) vs 19(8-40)%, p<0.01] while the NL one did not show any difference within the group. The highest concentration of Ach at the 21th week pointed to endothelial-dependent microvascular dysfunction in RL compared to NL [3(8-26) vs. 13(8-26)%, p<0.05]. Endothelial-independent microvascular reactivity was similar between groups. Our data suggest that postnatal overnutrition is associated to muscle endothelial-dependent microvascular dysfunction, greater body mass and total percentage of fat and impaired the lipid profile. In conclusion, the imprinting promoted by this experimental model of obesity was able to influence microvascular reactivity later in life.