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Biomedical subjects

F Zhu

Publications and source records attributed to F Zhu.

At least 19 recordsLinked to original sources
PubMed1999

Sum of segmental bioimpedance analysis during ultrafiltration and hemodialysis reduces sensitivity to changes in body position.

BACKGROUND: Bioimpedance, a noninvasive technique to analyze body composition, has attracted interest in determining body hydration in hemodialysis patients. However, the so-called whole-body (wrist-to-ankle) bioimpedance analysis (WBIA) is sensitive to changes in regional fluid distribution and tends to underestimate fluid changes during ultrafiltration in hemodialysis patients. The aim of this study was to show that volume changes calculated from a new approach, that is, segmental bioimpedance analysis (SBIA), are not affected by changes in body position. METHODS: Ten male patients (age 44 +/- 8 years, target weight 70.8 +/- 10 kg) were studied during their regular hemodialysis treatment while maintaining either a sitting or a supine body position throughout the study. Extracellular volume was calculated from extracellular resistance obtained from bioimpedance data measured for a range of frequencies (5 to 500 kHz) using the Xitron BIS4000B analyzer. Wrist-to-ankle measurements were compared with segmental arm, trunk, and leg measurements. RESULTS: Changes in extracellular volume estimated from wrist-to-ankle measurements only reached 80 +/- 13% and 65 +/- 17% of the actual change in body mass during sitting and supine dialysis treatments, respectively. However, when segmental measurements were analyzed, the calculated change in extracellular volume was 101 +/- 6% and 100 +/- 3% of the actual change in body mass during the sitting and supine treatments, respectively. CONCLUSIONS: SBIA properly identifies regional fluid changes and provides an appropriate measure of fluid changes caused by ultrafiltration and hemodialysis. The volume estimation based on the sum of segmental bioimpedance measurements is independent of body position, which is a prerequisite for applications in everyday practice.

Adult↗
PubMed1998

LIGHT, a novel ligand for lymphotoxin beta receptor and TR2/HVEM induces apoptosis and suppresses in vivo tumor formation via gene transfer.

LIGHT is a new member of tumor necrosis factor (TNF) cytokine family derived from an activated T cell cDNA library. LIGHT mRNA is highly expressed in splenocytes, activated PBL, CD8(+) tumor infiltrating lymphocytes, granulocytes, and monocytes but not in the thymus and the tumor cells examined. Introduction of LIGHT cDNA into MDA-MB-231 human breast carcinoma caused complete tumor suppression in vivo. Histological examination showed marked neutrophil infiltration and necrosis in LIGHT expressing but not in the parental or the Neo-transfected MDA-MB-231 tumors. Interferon gamma (IFNgamma) dramatically enhances LIGHT-mediated apoptosis. LIGHT protein triggers apoptosis of various tumor cells expressing both lymphotoxin beta receptor (LTbetaR) and TR2/HVEM receptors, and its cytotoxicity can be blocked specifically by addition of a LTbetaR-Fc or a TR2/HVEM-Fc fusion protein. However, LIGHT was not cytolytic to the tumor cells that express only the LTbetaR or the TR2/HVEM or hematopoietic cells examined that express only the TR2/HVEM, such as PBL, Jurkat cells, or CD8(+) TIL cells. In contrast, treatment of the activated PBL with LIGHT resulted in release of IFNgamma. Our data suggest that LIGHT triggers distinct biological responses based on the expression patterns of its receptors on the target cells. Thus, LIGHT may play a role in the immune modulation and have a potential value in cancer therapy.

Apoptosis↗
PubMed1998

A viral gene that activates lytic cycle expression of Kaposi's sarcoma-associated herpesvirus.

Herpesviruses exist in two states, latency and a lytic productive cycle. Here we identify an immediate-early gene encoded by Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus eight (HHV8) that activates lytic cycle gene expression from the latent viral genome. The gene is a homologue of Rta, a transcriptional activator encoded by Epstein-Barr virus (EBV). KSHV/Rta activated KSHV early lytic genes, including virus-encoded interleukin 6 and polyadenylated nuclear RNA, and a late gene, small viral capsid antigen. In cells dually infected with Epstein-Barr virus and KSHV, each Rta activated only autologous lytic cycle genes. Expression of viral cytokines under control of the KSHV/Rta gene is likely to contribute to the pathogenesis of KSHV-associated diseases.

Amino Acid Sequence↗
PubMed1998

Simple high-performance liquid chromatographic determination of the protease inhibitor indinavir in human plasma.

Indinavir is a member of a class of protease inhibitors that actively prevent the acquired immunodeficiency syndrome virion from maturing. A high-performance liquid chromatographic (HPLC) assay was developed and validated for the determination of indinavir in human plasma. Indinavir and the internal standard were isolated from the plasma by ether extraction. The residue after evaporation of ether was reconstituted with buffer and injected onto a C4 reversed-phase column eluted isocratically with a mobile phase consisting of 35:65 (v/v) of acetonitrile and buffer. A wavelength of 210 nm was found to be optimum for detection. The calibration range of this assay was from 10 to 5000 ng/ml and coefficients of variation for the assay ranged from 4.6% to 11.0% for three different drug concentrations and the limit of quantitation was 10 ng/ml. During the validation, short-term stability of the drug in plasma, stability during heat deactivation and on repeated freezing and thawing of plasma was evaluated. The overall recovery of indinavir by the ether extraction method was 91.4%. This HPLC assay was found to be a simple and reproducible method for monitoring indinavir levels in human plasma obtained during clinical trials of the drug.

Buffers↗
PubMed1998

Dynamics of segmental extracellular volumes during changes in body position by bioimpedance analysis.

Extracellular volume (ECV) of arms, trunk, and legs determined from segmental bioimpedance data in 11 healthy men (31.6 +/- 7 yr) obtained at the end of a 30-min equilibration phase in the supine body position was compared with ECV determined from whole body measurements (ECVWB). ECV was calculated from extracellular resistance (RECV) identified from the bioimpedance spectrum for a range of 10 frequencies. Whole body RECV (527.6 +/- 55.6 Omega) was equal to the sum of RECV in the arms, trunk, and legs (241.6 +/- 36. 3, 49.2 +/- 5.1, and 236.3 +/- 25.5 Omega, respectively). The sum of equilibrated ECV in arms (1.31 +/- 0.25 liters), trunk (10.08 +/- 1.65 liters), and legs (2.80 +/- 0.82 liters) was smaller than ECVWB (20.90 +/- 2.59 liters). In six subjects who changed from a standing to a supine body position, ECV decreased in arms (-2.59 +/- 2.51%, P = NS) and legs (-10.96 +/- 3.02%, P < 0.05) but increased in the trunk (+4.2 +/- 3.2%, P < 0.05). ECVWB also decreased (-4.98 +/- 1. 41%, P < 0.05). However, the sum of segmental extracellular volumes remained unchanged (-0.06 +/- 0.07%, P = NS). The sum of segmental ECVs is not sensitive to changes in body position, which otherwise interferes with the estimation of ECV in bioimpedance analysis when ECVWB is used.

Adult↗
PubMed1997

Ribozyme-mediated high resistance against potato spindle tuber viroid in transgenic potatoes.

A hammerhead ribozyme [R(-)] targeting the minus strand RNA of potato spindle tuber viroid (PSTVd) and a mutated nonfunctional ribozyme [mR(-)] were designed, cloned, and transcribed. As predicted, both monomer and dimer transcripts of the active R(-) ribozyme gene could cleave the PSTVd minus strand dimer RNA into three fragments of 77, 338, and 359 bases in vitro at 25 and 50 degrees C. The tandem dimer genes of R(-) and mR(-) were subcloned separately into the plant expression vector pROK2. Transgenic potato plants (cultivar Desirée) were generated by Agrobacterium tumefaciens-mediated transformation. Twenty-three of 34 independent transgenic plant lines expressing the active ribozyme R(-) resulted in having high levels of resistance to PSTVd, being free of PSTVd accumulation after challenge inoculation with PSTVd, but the remaining lines showed weaker levels of resistance to PSTVd with low levels of PSTVd accumulation. In contrast, 59 of 60 independent transgenic lines expressing the mutated ribozyme mR(-) were susceptible to PSTVd inoculation and had levels of PSTVd accumulation similar to that of the control plants transformed with the empty vector. The resistance against PSTVd replication was stably inherited to the vegetative progenies.

Base Composition↗
PubMed1997

[Clinical obeservation of improved passing peritoneum extraperitoneal cesarean sectron].

One hundred and fifty puerperas who had indications for cesarean section and factors associated with intrauterine infection were random divided into three groups and adopted three different operative proccdures which were improved passing peritoneum extraperitoneal, extraperitoneal and low segement cesarean section respectively. Three were 50 puerperas in each group, seven paremeters were observed during and after operation. The results showed that the mean times of three groups from cutting skin to fetal head delivered were 19.5, 22.6 and 19.9 minutes respectively (P < 0.05), the mean operative times were 58.04, 68.2 and 72.0 minutes in proper urder (P < 0.01). Gastrointestinal function recovery mean times were 26.6, 26.0 and 47.9 hours (P < 0.01) in sequence. Postoperative morhidity rates were 10%, 12% and 24% (P < 0.01) in order. Postoperative comlicatins were 0%, 26% and 6% (P < 0.01). There were no significant difference both in newborn one minute Apgar grading and blood loss volume during the operation in three groups. Improved passing peritoneun extraperitoneal cesarean section is a simple, convenient, safe and practical oprative method. It is especially applied to those cases who have a bad form of uterine hypomere and factors of intrauterine infection.

Adult↗
PubMed1997

Study on enzyme electrode biosensor of choline.

Choline oxidase was immobilized at a hydrogen peroxide electrode and the enzyme electrode was used for the amperometric determination of choline. The linear range is 0-200 mg/L with a response time of 40 seconds and a 25-microliter sample injection. The relative standard deviation (RSD) is less than 1.5% in 20 assays. The enzyme membrane can be used continuously at 25 degrees C for 60 days. The recovery rate of this method is 100.3-102.3%.

Alcohol Oxidoreductases↗
PubMed1997

[Expression of green fluorescent protein with baculovirus vector in insect cells].

The green fluorescent protein (GFP) gene was subcloned into the transfer vector pVLneo downstream of the polyhedrin gene (ocu) promoter. Insect cells were cotransfected with recombinant plasmid and Autographa californica Nuclear Polyhedrosis Virus (AcNPV) DNA. In the presence of G418, the recombinant virus containing GFP gene was purified. The GFP expressed in insect cells with a Mw of 30 kDa is observable by strong green light under a fluorescent microscope. Excitation and emission spectra of the GFP were 395 nm and 509 nm respectively. Integration of GFP gene on AcNPV genome was identified directly by Southern blot which gave strong hybridization signal between GFP cDNA probe and 1 kb EcoRI fragment of recombinant virus.

Animals↗
PubMed1997

[Effects of aprotinin on heparinized whole blood activated clotting time and whole blood prothrombin time].

When aprotinin is used during cardiopulmonary bypass, there is a prolongation of the activated clotting time (ACT), which is used to monitor heparinization. The aim of this study was to observe the effects of aprotinin and heparin on whole blood ACT and whole blood prothrombin time (BPT). The results showed that when kaolin was used as the contact activator, the intrinsic clotting system was also inhibited by aprotinin, the observed ACTs with various dose aprotinin and concomitant heparin were significantly prolonged (Q = 0.757, P < 0.01). There was a dose-dependent prolongation of BPT by heparin (r = 0.985, P < 0.01). However, the heparin-mediated prolongation of BPT was not enhanced by aprotinin. The authors conclude that aprotinin prolongs heparinized whole blood activated clotting time but was not whole blood prothrombin time.

Adult↗
PubMed1996

[Diagnosis of chylous ascites with oral administration of 13C-palmitic acid].

12 cases of chylous ascites in PUMC hospital in the recent 30 years were analysed. The etiology of this disease includes non-traumatic (83.3%) and traumatic (16.7%) causes. All the patients received isotope examination or lymphangiography, but only in 8 patients the site of the lesion was found. As these two kinds of examination can only show the lesions in the right and left lumbar lymph trunks, cisterna chyli and throacic duct but not the intestinal lymph truck, the authors set up a method by administering orally 13C-palmitic acid to detect the lesion of intestinal lymph trunk. Palmitic acid is a long-chain fatty acid, which enters directly into the intestinal lymph trunk after absorption. Palmitic acid labelled with 13C could be detected in the ascitic fluid if there is a leak from intestinal lymph trunk. This new method was used to examine a patients who had negative results with isotope examination and lymphangiography; 13C could be detected in the ascitic fluid 30 minutes after oral administration but not in exhaled air. It can be concluded that cyhle leaked into the peritoneal cavity from the intestinal lymph trunk. This method is also of help to determine the possible site of leakage and the degree of obstruction, so it is quite useful for the diagnosis of chylous ascities.

Administration, Oral↗
PubMed1995

A hybrid-hybrid matrix method for 3D NOE-NOE data analysis.

A hybrid-hybrid matrix method is described that quantitatively analyzes 3D NOE-NOE NMR data. Experimental 3D data are merged with simulated 3D data to create a hybrid 3D NOE-NOE spectrum. This is then deconvoluted into a 2D hybrid NOESY spectrum. The deconvoluted, 2D hybrid NOESY spectrum can then be merged with other 2D NOESY experimental data along with additional simulated 2D data as necessary to create a hybrid-hybrid 2D NOE volume matrix. This hybrid-hybrid volume matrix is then used with the complete relaxation program, MORASS, to calculate a rate matrix, and the resulting distances taken from the off-diagonal cross-relaxation rates can then be utilized in a distance geometry or restrained molecular-dynamics refinement of the structure. This process is repeated until a satisfactory agreement between the calculated and observed 3D volumes is obtained. This hybrid-hybrid matrix method retains computational efficiency and utilizes the resolution of the 3D data set while retaining any information content of the available 2D data. The initial tests of the deconvolution algorithm give high correlation results even with the introduction of random error into the 3D data set. Our results suggest that the hybrid-hybrid matrix method for analysis of 3D NOE-NOE spectra may provide a viable tool in the refinement of large molecules.

Algorithms↗