Characterizing the Effects of Heparin Gel Stiffness on Function of Primary Hepatocytes

In the liver, hepatocytes are exposed to a large array of stimuli that shape hepatic phenotype. This in vivo microenvironment is lost when hepatocytes are cultured in standard cell cultureware, making it challenging to maintain hepatocyte function in vitro. Our article focused on one of the least studied inducers of the hepatic phenotype—the mechanical properties of the underlying substrate. Gel layers comprised of thiolated heparin (Hep-SH) and diacrylated poly(ethylene glycol) (PEG-DA) were formed on glass substrates via a radical mediated thiol–ene coupling reaction. The substrate stiffness varied from 10 to 110 kPa by changing the concentration of the precursor solution. ELISA analysis revealed that after 5 days, hepatocytes cultured on a softer heparin gel were synthesizing five times higher levels of albumin compared to those on a stiffer heparin gel. Immunofluorescent staining for hepatic markers, albumin and E-cadherin, confirmed that softer gels promoted better maintenance of the hepatic phenotype. Our findings point to the importance of substrate mechanical properties on hepatocyte function

Aerobic bacteria, Chlamydia trachomatis, Pneumocystis carinii and Cytomegalovirus as agents of severe peneumonia in small infants Bactérias aeróbias, Chlamydia trachomatis, Pneumocystis carinii e Cytomegalovirus: agentes causadores de pneumonia grave em pequenos lactentes

The authors studied 58 infants hospitalized for pneumonia in a semi-intensive care unit. Age ranged from 1 complete to 6 incomplete months. The infants were sent from another hospital in 20 cases and from home in a further 38. Pulmonary involvement, which was alveolar in 46 cases and interstitial in 12, was bilateral in 31 children. The investigation was carried out prospectively on the etiological agents associated with respiratory infection to look for evidence of aerobic bacteria (blood cultures), Chlamydia trachomatis and Cytomegalovirus (serology), and Pneumocystis carinii (direct microscopy of tracheal aspirated material). The following infectious agents were diagnosed in 21 children (36.2%): Aerobic bacteria (8), Chlamydia trachomatis (5), Pneumocystis carinii (3), Cytomegalovirus (3), Cytomegalovirus and Chlamydia trachomatis (1), Aerobic bacteria and Cytomegalovirus (1). Seven cases of infection by Chlamydia trachomatis and/or Cytomegalovirus were diagnosed out of the 12 cases with pulmonary interstitial involvement.<br>Os autores estudaram prospectivamente 58 lactentes internados por pneumonia em unidade semi-intensiva. A idade foi limitada entre 1 mês completo e 6 meses incompletos. A procedência das crianças foi de outro hospital em 20 casos e domiciliar em 38. O acometimento pulmonar era alveolar em 46 casos, intersticial em 12 e bilateral em 31 crianças. Foram pesquisados agentes etiológicos associados à infecção respiratória dos lactentes jovens: Bactérias aeróbias (Hemoculturas), Chlamydia trachomatis e Cytomegalovirus (sorologia), e Pneumocystis carinii (microscopia direta do aspirado traqueal). Foram diagnosticadas infecções em 21 crianças (36,2%): Bactérias aeróbias (8), Chlamydia trachomatis (5), Cytomegalovirus (3), Pneumocystis carinii (3), Cytomegalovirus e Chlamydia trachomatis (1), Bactéria aeróbia e Cytomegalovirus (1). Foram diagnosticadas 7 infecções por Chlamydia trachomatis e/ou Cytomegalovirus entre as 12 crianças com quadro intersticia