Biomedical subjects

Y L Li

Publications and source records attributed to Y L Li.

130 records · Page 8Linked to original sources

PubMedDate not supplied

Heparin-coupled poly(poly(ethylene glycol) monomethacrylate)-Si(111) hybrids and their blood compatible surfaces.

Well-defined (nearly monodispersed) poly(poly(ethylene glycol)monomethacrylate)-Si hybrids were prepared via surface-initiated atom transfer radical polymerization (ATRP) of the poly(ethylene glycol)monomethacrylate (PEGMA) macromonomer on the hydrogen-terminated Si(111) surface (Si-H surface). Both the active chloride groups at the chain ends (from the ATRP process) and the chloride groups converted from some ( approximately 32%) of the -OH groups of the Si-C bonded PEGMA polymer, or P(PEGMA), brushes were used as leaving groups for the covalent coupling of heparin. For the heparinized P(PEGMA)-Si hybrid surfaces, protein adsorption and platelet adhesion were significantly suppressed. The well-defined and dense P(PEGMA) brushes, prepared from surface-initiated ATRP, had allowed the immobilization of a relatively high concentration of heparin (about 14 mug/cm(2)). The resulting silicon surface exhibited significantly improved antithrombogenecity with a plasma recalcification time (PRT) of about 150 min. The persistence of high bioactivity for the immobilized heparin on the hybrid surfaces can be attributed to the biocompatibility of the PEGMA units, as well as their role as spacers in providing the immobilized heparin with a higher degree of conformational freedom in a more hydrophilic environment. Thus, the heparin-coupled P(PEGMA)-Si hybrids with anti-fouling and antithrombogenic surfaces are potentially useful in silicon-based implantable devices and tissue engineering.

Acrylates↗

PubMedDate not supplied

Hemodynamic effects of centrally administered adrenomedullin (13-52) in anesthetized rats.

This study was conducted to investigate the effect of intracerebroventricular administration of adrenomedullin (13-52) [ADM(13-52)], a novel hypotensive peptide, on the hemodynamic parameters of anesthetized rats. ADM(13-52) was administered centrally in a dose of 0.4-3.2 nmol/kg. It provoked marked, prolonged and dose-dependent increases in mean arterial blood pressure, heart rate, stroke volume, cardiac index, left ventricular pressure, left ventricular dp/dtmax and dp/dtmin, but reduction in total peripheral resistance index. In addition, intracerebroventricular administration of ADM(13-52; 1.6 nmol/kg) provoked a marked increase in renal sympathetic nerve activity. Intracerebroventricular administration of artificial cerebrospinal fluid had no effect on the hemodynamic parameters and renal sympathetic nerve activity. The results indicate that ADM(13-52) exerts a central action on the cardiovascular system. The mechanisms of hemodynamic changes induced by central ADM(13-52) were preliminarily analyzed in this study. ADM might play a role in the central control of the cardiovascular system, although the confirmed mechanisms and the physiological implications are undetermined.

Adrenomedullin↗

PubMedDate not supplied

Auditory evoked potentials in audiometric assessment of compensation and medicolegal patients.

The clinical utility of auditory evoked potentials for validation of the pure tone audiogram in adult compensation claimants and medicolegal patients is examined. Large sample comparisons of evoked potential and conventional pure tone thresholds showed that the slow vertex response can estimate true hearing levels within 10 dB in almost all patients. Given adequate tester skills, it is the tool of choice, and it merits more widespread implementation. Properly used, it can improve and abbreviate the assessment battery for detection and quantification of nonorganic hearing loss. The 40-Hz middle latency response is useful as a secondary tool, but at present, cochlear nerve and brain stem potentials have limited audiometric value in this population.

Adult↗

PubMedDate not supplied

Comparison of H2-receptor antagonist- and proton-pump inhibitor-based triple regimens for the eradication of Helicobacter pylori in Chinese patients with gastritis or peptic ulcer.

This study compared the efficacy of an H2-receptor antagonist (H2RA)- and a proton-pump inhibitor (PPI)-based triple regimen for the eradication of Helicobacter pylori infection. Chinese patients with H. pylori-associated gastritis or peptic ulcer were randomized to receive the H2RA-based triple regimen (20 mg famotidine, 1.0 g amoxicillin and 0.4 g metronidazole) or the PPI-based triple regimen (20 mg omeprazole, 1.0 g amoxicillin and 0.4 g metronidazole) both twice daily for 1 or 2 weeks. Successful eradication of H. pylori was determined by the 13C-urea breath test and gastric mucosa histology at least 4 weeks after completion of antibiotic therapy. Eradication rates were 56.0% and 76.9% for the 1-week H2RA- and PPI-based triple regimens, respectively, and 81.6% and 82.1% for the 2-week regimens, respectively. The H. pylori eradication rate for the 2-week H2RA regimen was significantly higher than that for the 1-week regimen, but there were no significant differences between the 1- and 2-week PPI regimens. The two regimens proved equally effective in eradicating H. pylori infection.

Adolescent↗