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Biomedical subjects

Z Lu

Publications and source records attributed to Z Lu.

459 records · Page 26Linked to original sources
PubMedDate not supplied

Chemical synthesis and surface activity of lung surfactant phospholipid analogs. III. Chiral N-substituted ether-amide phosphonolipids.

A homologous series of chiral (R) ether-amide phosphonolipid analogs of naturally occurring (R) glycerophospholipids were synthesized and characterized for their interfacial behaviors. The phosphonolipids possess isoteric ether, amide, and phosphonate functions at positions corresponding to the sn-1, sn-2, and sn-3 ester functions, respectively, of naturally occurring glycerophospholipids. All compounds were synthesized with disaturated C16:0 alkyl/acyl moieties to give structural analogy with dipalmitoyl phosphatidylcholine (DPPC), the major glycerophospholipid component of lung surfactant. Further substitutions at the headgroup nitrogen were also used to generate differences in headgroup size and polarity in the synthetic compounds. The surface activity of the ether-amide phospholipids was investigated in terms of adsorption to the air-water interface, together with studies of dynamic respreading after monolayer collapse and surface tension lowering in dynamically compressed spread films and dispersions. Results showed that several ether-amide phosphonolipids had more rapid adsorption and improved dynamic respreading behavior compared to DPPC, plus the ability to lower surface tension into the range of less than 1 to 4 mN/m in spread films and in dispersions under dynamic conditions. In combination with a series of diether phosphonolipids synthetized in a companion study [1], these ether-amide compounds are useful in the development of molecular structure-surface activity correlates for lung surfactant-related materials, and should assist in investigating the specificity of interactions between phospholipids and other pulmonary biological molecules.

Amides↗
PubMedDate not supplied

A new stabilizer used in microencapsulation.

In this communication, a new microencapsulation method is reported to entrap solid drug powder in an aqueous system. A hydrophobically modified, random polyacrylamide derivative was used as a stabilizer: with a hydrophilic back bone and hydrophobic side chain, it showed good dispersing and stabilizing effects in the preparation of microcapsules. The preparation of streptomycin microcapsules, using poly(lactide) and poly(caprolactone), showed the successful entrapment of streptomycin powder which is readily soluble in water (solubility larger than 20 mg/ml). In addition, a low concentration of stabilizer (0.25%) is used and a short preparation process is also an advantage of the method.

Acrylic Resins↗
PubMedDate not supplied

New tumor markers: CA125 and beyond.

A variety of biomarkers have been developed to monitor growth of ovarian cancer and to detect disease at an early interval. CA125 (MUC16) has provided a useful serum tumor marker for monitoring response to chemotherapy, detecting disease recurrence, distinguishing malignant from benign pelvic masses, and potentially improving clinical trial design. A rapid fall in CA125 during chemotherapy predicts a favorable prognosis and could be used to redistribute patients on multiarmed randomized clinical trials. Several studies now document that CA125 can serve as a surrogate marker for response in phase II trials. Serial measurement of CA125 might also provide a useful marker for monitoring stabilization of disease with cytostatic targeted therapeutic agents. The greatest potential for serum markers may be in detecting ovarian cancer at an early stage. A rising CA125 can be used to trigger transvaginal sonography (TVS) in a small fraction of patients. An algorithm has been developed that calculates risk of ovarian cancer based on serial CA125 values and refers patients at highest risk for TVS. Use of the algorithm is currently being evaluated in a trial with 200,000 women in the UK that will test critically the ability of a two-stage screening strategy to improve survival in ovarian cancer. Whatever the outcome, as 20% of ovarian cancers have little or no expression of CA125, additional serum markers will be required to detect all patients in an initial phase of screening. More than 30 serum markers have been evaluated alone and in combination with CA125 by different investigators. Some of the most promising include: HE4, mesothelin, M-CSF, osteopontin, kallikrein(s), and soluble EGF receptor. Two proteomic approaches have been used: one examines the pattern of peaks on mass spectroscopy and the other uses proteomic analysis to identify a limited number of critical markers that can be assayed by more conventional methods. Both approaches are promising and require further development. Several groups are placing markers on multiplex platforms to permit simultaneous assay of multiple markers with very small volumes of serum. Mathematical techniques are being developed to analyze combinations of marker levels to improve sensitivity and specificity. In the future, serum markers should improve the sensitivity of detecting recurrent disease as well as facilitate earlier detection of ovarian cancer.

Biomarkers, Tumor↗
PubMedDate not supplied

beta-Adrenoceptors in endothelium of rabbit coronary artery and alteration in atherosclerosis.

The existence of beta-adrenoceptor (beta-AR) in endothelium of rabbit coronary artery and its alteration in atherosclerosis (AS) were determined by relaxation experiments in isolated preparations and in situ hybridization with a digoxigenin-labelled beta 2-AR cDNA probe. The concentration-relaxing response curves for isoproterenol (ISO) and norepinephrine (NE) in the presence of phentolamine were shifted to the right, and the maximal relaxations were reduced by removing the endothelium. Nitric oxide synthase inhibitor L-NG-nitro-arginine reduced the maximal relaxation induced by ISO, while the cyclooxygenase inhibitor indomethacin showed no effect on relaxation. In situ hybridization showed that mRNA for beta-AR was detected not only in smooth muscles, but also in endothelial cells. Coronary artery AS was created by high cholesterol feeding and was confirmed histologically under light microscopy. The relaxation response to acetylcholine (ACh) was abolished or significantly diminished in AS preparations. The relaxation responses to ISO or NE, however, were potentiated in AS arteries, especially in those which showed diminished (but not abolished) ACh response. The relaxation induced by sodium nitroprusside was reduced significantly in the AS arteries. Those results suggest that beta-AR are present in endothelium of rabbit coronary artery, and that endothelium beta-AR-mediated vasorelaxation is potentiated in AS.

Animals↗
PubMedDate not supplied

Computer knowledge, attitudes, and skills of nurses in People's Hospital of Beijing Medical University.

The first Chinese Hospital Information Systems (HIS) was used as a pilot project at People's Hospital, of Beijing Medical University (BMU). To assess the computer knowledge, attitudes, and skills of nurses working in the hospital, and to examine the relationships among these factors, 169 staff nurses working on clinical units were surveyed by proportionate stratified random sampling. Computer knowledge, attitudes, and skills were measured, by a nurses' computer knowledge questionnaire (NCKQ), nurses' computer attitude scale (NCAS), and nurses' computer skill scale (NCSS), respectively, developed by the investigators. Data analysis showed that the overall computer knowledge and skills of nurses were at moderate levels and the computer attitudes were neutral. Nurses' computer skills were significantly and positively correlated with both computer knowledge and computer attitudes; however, no significant correlation was found between computer knowledge and computer attitudes. Strategies to enhance nurses' computer knowledge, attitudes, and skills were proposed.

Adult↗
PubMedDate not supplied

Amplification of Salmonella chromosomal DNA using the polymerase chain reaction.

A Salmonella-specific polymerase chain reaction (PCR) was developed and standardized. The origin of the primers was a recombinant clone (C7) that contained Salmonella-specific HindIII fragment DNA of 2.1-kilobase pairs. Based on the sequence data of Salmonella enteritidis recombinant clone C7, two primers designated NK1 (21 nucleotides) and NK2 (24 nucleotides) were synthesized for use in the PCR. A Salmonella-specific 2.0-kilobase pair DNA product was amplified by the primers from 23 species of Salmonella, but not from 19 enteric and non-enteric bacteria. As little as 330 fg of Salmonella DNA was detected using either ethidium bromide/ultraviolet exposure of gels or Southern blot hybridization with a C7 clone.

Animals↗
PubMedDate not supplied

A study of effects of WGA and ConA on RBC membrane receptors using a new ektacytometric method.

With a new ektacytometry, we studied the relation between the microstructure of red blood cell (RBC) membrane and the rheological properties of RBCs in a shear flow field of low viscosity. The main contributions of this paper are as follows: 1. The hemorheological meanings of the orientation index (DI)or and the small deformation index (DI)d were explored. (DI)or is an overall rheological index depending on the deformability and morphology of RBCs. The better the physiological shape of RBCs is maintained, the greater the (DI)or is. (DI)d can be used to describe the lipid fluidity of RBC membrane. Such an explanation for the meaning of (DI)d has been forcefully supported by our experiments using electron spin resonance (ESR) and fluorescence polarization. 2. The influence of wheat germ agglutinin (WGA) of different concentrations on the lipid fluidity of membrane is different from that of concanavalin A (ConA). The lipid fluidity of membrane changes with WGA concentration treating RBCs and there is a maximum value for the membrane fluidity at a specific concentration of WGA. However, the deformability of membrane described by the integrate deformation index (IDI) monotonically decreased with the increase in WGA concentration treating RBCs. 3. It is concluded that the increase in the lipid fluidity of red cell membrane is not necessarily associated with the improvement of RBC deformability.

Animals↗