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Biomedical subjects

Y L Li

Publications and source records attributed to Y L Li.

At least 127 records · Page 7Linked to original sources
PubMed1987

The relationship between cations and blood pressure in the People's Republic of China.

Blood pressure was measured in the north and in the south of the People's Republic of China in 1002 men and 1006 women. The 24-hour urinary excretion of sodium, potassium, calcium, magnesium, and creatinine was measured, and the relationship between urinary cations and blood pressure was studied. Blood pressure and 24-hour sodium excretion were higher in northern China than in southern China. With some exceptions, a positive correlation was found between urinary sodium and blood pressure and a negative one between 24-hour urinary potassium excretion and blood pressure. Urinary calcium correlated negatively and urinary magnesium did not correlate significantly with blood pressure. The sodium/potassium ratio correlated positively with blood pressure, and the calcium/magnesium ratio, negatively. This study confirms the positive within-population relationship between sodium intake and blood pressure in Oriental populations.

Anthropometry↗
PubMedDate not supplied

Metabolism of polynuclear aromatic hydrocarbon in human term placenta influenced by cigarette smoke exposure.

The relative contributions of biologic and environmental factors on embryo-fetal development were elucidated in a population of pregnant women who were exposed to varying amounts of active cigarette smoke and women who were not exposed to cigarette smoke. The neonatal weight at birth, placental weight at delivery, duration of pregnancy, and placental xenobiotic (polynuclear aromatic hydrocarbon, PAH) metabolism potential were assessed in this population. The overall metabolic capability in exposed and unexposed placental tissue was measured by in vitro assays using microsomes and a PAH substrate, benzo[a]pyrene (B[a]P). Toxicity potential was determined by B[a]P-metabolite-DNA adduct generation under the same incubation condition. Cigarette smoke exposure increased the overall PAH metabolism potential in placental tissues by approximately 200% (nonsmoker 176.2 +/- 33.6, n = 25; smoker 524.5 +/- 75.5, n = 32 pmol/mg protein) whereas PAH-DNA adduct formation potential did not increase significantly over the basal level (nonsmoker 5002 +/- 830, n = 15; smoker 6172 +/- 1443, n = 22 fmol B[a]P equivalent/mumol DNA/mg protein). Exposure to cigarette smoke during pregnancy is deleterious to fetal development as reflected by reduced neonatal weight at birth. In contrast, placental weight reduction is indistinct, but placentae expressed markedly augmented overall xenobiotic (PAH) metabolism capability in response to cigarette smoke exposure during pregnancy, indicating placental metabolism may be an important mediator of adverse effects induced by such xenobiotic exposure.

Analysis of Variance↗
PubMedDate not supplied

Covalent immobilization of glucose oxidase on well-defined poly(glycidyl methacrylate)-Si(111) hybrids from surface-initiated atom-transfer radical polymerization.

A simple one-step procedure was employed for the covalent immobilization of an atom-transfer radical polymerization (ATRP) initiator, via the robust Si-C bond, on the hydrogen-terminated Si(111) surface (Si-H surface). Well-defined poly(glycidyl methacrylate) [P(GMA)] brushes, tethered directly on the (111)-oriented single-crystal silicon surface, were prepared via surface-initiated ATRP. Kinetics study on the surface-initiated ATRP of glycidyl methacrylate revealed that the chain growth from the silicon surface was consistent with a "controlled" process. A relatively high concentration of glucose oxidase (GOD; above 0.2 mg/cm2) could be coupled directly to the well-defined P(GMA) brushes via the ring-opening reaction of the epoxide groups with the amine moieties of the enzyme. The resultant GOD-functionalized P(GMA) brushes, with the accompanying hydroxyl groups from the ring-opening reaction of the epoxide groups, serves as an effective spacer to provide the GOD with a higher degree of conformational freedom and a more hydrophilic environment. An equivalent enzyme activity above 1.6 units/cm2 [micromoles of beta-D-(+)-glucose oxidized to d-gluconolactone per minute per square centimeter] and a corresponding relative activity of about 60% could be readily achieved. The immobilized GOD also exhibited an improved stability during storage over that of the free enzyme. The GOD-functionalized silicon substrates are potentially useful to the development of silicon-based glucose biosensors.

Biosensing Techniques↗