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Biomedical subjects

J Z Li

Publications and source records attributed to J Z Li.

At least 55 records · Page 3Linked to original sources
PubMed1993

Mechanism of platelet aggregation induced by a monoclonal antibody requiring Fc portion.

A monoclonal antibody designated Apt4, which is IgG1, was produced by fusion of mouse myeloma cells to spleen cells from a BALB/c mouse immunized with normal human platelets. Apt4 whole IgG caused the aggregation of both platelet rich plasma (PRP) and washed platelets from normal subjects and a patient with Bernard Soulier syndrome but not those from two patients with the Type 1 Glanzmann's thrombasthenia. No aggregation was observed when Apt4 F(ab')2 fragments were used. Immunofluorescence study showed that both whole IgG and F(ab')2 fragments of Apt4 bound to fresh or formalin fixed platelets from normal subjects and a patient with Bernard Soulier syndrome but not to those from two patients with Glanzmann's thrombasthenia. Aggregation induced by Apt4 IgG was inhibited by EDTA (10 mM), PGE1 (1 mM), 2-deoxy-D-glucose/antimycin (1.4 uM), and apyrase (20 units/ml). Preincubation of normal PRP with monoclonal anti-GPIIb/IIIa or anti-GPIb antibodies completely or partially inhibited the Apt4-induced aggregation, whereas anti-GPIIIa antibodies have no effects on this activation. Monoclonal ant-Fc gamma RII antibody (IV.3) inhibited Apt4 induced aggregation. Immunoprecipitation of 125I-labeled platelet membrane lysate by Apt4 IgG showed two protein bands with a molecular weight of 145,000 and 95,000 daltons respectively under non-reducing condition, which are corresponding to GPIIb and GPIIIa. In conclusion, Apt4 antibody binds to GPIIb/IIIa complex and induces aggregation, requiring energy metabolism, calcium, ADP release and Fc portion of IgG to interact with Fc receptor, but independent of thromboxane A2 formation.

Animals↗
PubMed1993

[Antitumor effect of the immunoconjugate composed of antibiotic C1027 and Fab fragment from a monoclonal antibody directed against human hepatoma].

Antibiotic C1027, a macromolecular peptide with highly potent cytotoxicity to cultured cancer cells, was conjugated to monoclonal antibody 3A5 and its Fab fragment separately using SPDP as the linker agent. McAb 3A5, identified as IgG1, was directed against human hepatoma BEL-7402 cells. By ELISA, McAb 3A5 and the Fab fragment were strongly reactive with hepatoma cells and weakly reactive with KB cells. Determined by clonogenic assay against hepatoma BEL-7402 cells, the IC50 values for McAb-C1027, Fab-C1027 and C1027 were 4.2 x 10(-14), 8.6 x 10(-16) and 6.5 x 10(-16) mol.L-1, respectively. Fab-C1027 was 49-fold more potent than McAb-C1027 in cytotoxicity. Moreover, Fab-C1027 was 160-fold more potent in cytotoxicity to hepatoma cells than to KB cells, indicating selective cytotoxicity of Fab-C1027 conjugate to the target cells. Therapeutic effect of the conjugate was evaluated with hepatoma BEL-7402 xenograft in nude mice. After subcutaneous transplantation of the tumor, treatment started on day 3, iv, with equivalent dose of C1027, 0.1 mg.kg-1 x 6. Fab-C1027 and free C1027 inhibited tumor growth by 85% and 59%, respectively. Fab-C1027 conjugate showed more marked antitumor effect in vivo than free C1027.

Aminoglycosides↗
PubMed1993

Correlation of serum cholesteryl ester fatty acid composition with susceptibility to atherosclerosis in different species.

Fatty acid composition of serum cholesteryl esters (CEs) in Chinese and 9 species of laboratory animals was analysed. Polyunsaturated fatty acids (PUFAs) were the predominant fatty acids in CEs. A close correlation between PUFAs to saturated fatty acids ratio (P/S) in CEs and susceptibility to atherosclerosis (AS) was observed in different species. Animals with high P/S such as mice (13.0), tree shrews (9.0) and rats (9.0) were AS-resistant, and those with low P/S such as rabbits (2.9) were susceptible to AS. The P/S value in men (4.9) was between those of the above two kinds of animals, and similar to those of pigs (4.2) and monkeys (3.7). Marked physiological significance of the rich PUFAs in CEs may be expected. As the main constituent of low density lipoprotein (LDL), CEs may provide PUFAs for cells efficiently via LDL receptor. It is assumed that PUFAs in CEs may play an important role in the metabolism of cholesterol and the development of AS by regulating LDL receptor activity, platelet function and prostaglandin metabolism.

Adult↗
PubMed1993

Serum cholesterol determined by liquid chromatography with 6-chlorostigmasterol as internal standard.

We describe an accurate and precise method for determining serum cholesterol by high-performance liquid chromatography (HPLC). After addition of 6-chlorostigmasterol as internal standard, serum is treated with alcoholic potassium hydroxide. Subsequently the cholesterol and internal standard are extracted from the mixture into n-hexane and then derivatized to phenylurethanes for measurement by HPLC with ultraviolet detection. The effective chromatographic separation and the use of an appropriate internal standard make this procedure free from interferences by other serum sterols and precise. The mean cholesterol concentration in Standard Reference Material (SRM) 909 (human serum) assayed by this procedure (4.346 mmol.g-1 x L-1) agreed well with the value assigned by the National Institute of Standards and Technology (4.359 mmol.g-1 x L-1). Within-run and total CVs were 0.56% and 0.78%, respectively. Therefore the performance of this procedure is sufficiently good to allow its use as a candidate reference method for serum cholesterol determination.

Cholesterol↗
PubMed1992

The effect of calcitonin-gene-related peptide on acute ischemia-reperfusion renal injury: ultrastructural and membrane lipid peroxidation studies.

It is well accepted that postischemic reperfusion promotes functional and morphological impairment which may be related to oxygen free-radical-mediated membrane damage. A new purified bioactive compound, calcitonin-gene-related peptide (CGRP), is known to be not only a potent vasodilator but also a cytoprotective agent. This study was designed to observe whether CGRP has a protective effect on the ischemic kidney. Male Sprague-Dawley rats were subjected to a 45-min period of renal ischemia followed by 60 min of reperfusion. At the beginning of the reperfusion, 12 rats were given intravenous saline and served as controls whereas 5 rats were given CGRP, 10 micrograms/kg intravenously. After reperfusion the kidneys were removed for light- and electronmicroscopy, and the lipid peroxidation product malonaldehyde (MDA) was assayed by thiobarbituric acid (TBA) colorimetry. The results demonstrated that the serum creatinine (Scr) and renal MDA content in the CGRP group were significantly lower than those in the control group. The mean values for Scr were 0.75 +/- 0.09 vs 0.93 +/- 0.05 mg/dL or 62.8 +/- 9.7 vs 82.2 +/- 4.4 mumol/L (p less than 0.05), respectively; while the mean values for MDA were 18.71 +/- 2.13 vs 30.32 +/- 1.78 nmol/100 mg (ww) (p greater than 0.05), respectively. The same signals of free radicals in the ischemic-reperfused kidney with or without CGRP were found by electron spin resonance. Morphological studies demonstrated that the treatment with CGRP ameliorated the ischemic-reperfusion injury to both renal brush borders and mitochondria. The results showed that CGRP has a protective action on ischemia-reperfusion renal injury by decreasing lipid peroxidation of membranes and suggest that it may be a beneficial agent for therapy of acute renal failure.

Animals↗
PubMed1992

[The value of fingernail creatinine measurement in the identification of acute and chronic renal failure].

It is difficult to distinguish acute renal failure (ARF) clinically from chronic renal failure (CRF), especially in the patients who do not have medical history records. Since fingernail creatinine (Ncr) reflects serum creatinine (Scr) at the time of nail formation, it has been suggested that Ncr level might represent that of Scr around 4 months previously. In this study, clipped fingernail specimens from 60 normal individuals (Scr 85.75 +/- 3.54 mumol/L), 35 patients with CRF (Scr 568.41 +/- 47.74 mumol/L) and 15 patients with ARF (Scr 123.60 +/- 17.29 mumol/L) were analyzed for creatinine by a standard alkaline picrate method. The results showed that Ncr level was significantly lower in the normal group (61.89 +/- 10.25 mumol/100g fingernail) than in the CRF group (130.04 +/- 34.55 mumol/100g fingernail) P less than 0.001. In the ARF group Ncr level (65.59 +/- 2.5 mumol/100g fingernail) was more or less the same as that in normal controls. It is concluded that Ncr measurement is of clinical value in identification of ARF.

Acute Kidney Injury↗
PubMed1991

Trace elements in human transitory milk. Variation caused by biological attributes of mother and infant.

Multielement analysis was performed on human milk collected on 5-9-d postpartum from 51 Japanese females using inductively coupled plasma (ICP) mass spectrometry (MS), ICP atomic emission spectrometry (ICP-AES) and fluorometry. Thirty-one elements were detected by these analytical methods in milk. Twelve elements (Na, Mg, P, S, K, Ca, Cu, Zn, Se, Sr, Rb, and Mo) were detected in all of the samples. Al, Cs, and Ba were the elements detected by ICP-MS in more than half of the samples. Multiple regression analysis extracted biological attributes of mother and infant, such as maternal stature, maternal wt, or infant's birth wt, as statistically significant factors contributing to the variation in elemental concentration in milk. However, the rates of contribution were small in all cases. It was concluded that the biological attributes of mother and infant examined in this study were not the major factors that contribute to elemental variation in human milk.

Anthropometry↗
PubMed1991

[Influence of atmospheric pressure fluctuation on condition of patients with cor pulmonale].

Based on investigation of 632 patients with cor pulmonale, we found that there were a close corresponding relationship of attack, exacerbation and death of patients to negative variation of daily atmospheric pressure. It was more obvious that the persistent and significant decrease in atmospheric pressure could influence the patient situation. The disease attacks usually appeared behind in negative variation of pressure changes, however, the death did before them. The mechanism of influences of atmospheric pressure changes on situation of patients with cor pulmonale were discussed preliminarily. The authors point out that the disease condition might be predicted by forecast and should take preventive measures to avoid it in advance.

Atmospheric Pressure↗
PubMed1991

[Nd: YAG laser iridotomy for angle-closure glaucoma].

56 eyes of primary angle-closure glaucoma were performed peripheral iridotomy with the domestic JYZ-1 Model YAG laser microruptor. The success rate was 100%. On the average, the number of laser shots was 5 (3.6-31) times, the shot energy was 212 (171-961) mJ, and the follow-up was 3.57 months. Postoperatively, the IOP was lowered by 2.43 mmHg. the use of hypotensive drugs diminished, and the index of chamber angle closure improved. The immediate operative complications were IOP elevation, iris bleeding, and anterior uveitis, which responded well to treatment.

Adult↗
PubMed1990

Detection of avian infectious bronchitis viral infection using in situ hybridization and recombinant DNA.

A recombinant DNA probe with specificity for the 3' end of genomic RNA from the Ark 99 strain of infectious bronchitis virus (IBV) was found to hybridize with extracted RNA of three strains with the Ark serotype, as well as the Mass41, Holl52, Gray, JMK, Conn, Fla and SE17 strains of IBV. Viral infection was detected in the cytoplasm of chicken embryo kidney cells inoculated with Mass41, Ark99, SE17 or two recent field isolates of IBV using in situ cytohybridization and a biotinylated probe. In vivo infections were detected in individual cells of tracheas and lungs 2,4, and 6 days after inoculation of chicks with Mass41 and Ark99. In situ hybridization of Ark99 infected tissue sections using 32P-dATP labelled probe indicated that more viral replication was present in the trachea on day 4 than either days 2 or 6; whereas more viral RNA was found in the lungs on day 6 than days 2 or 4 after inoculation.

Animals↗
PubMed1990

The production, purification, and bioactivity of recombinant bovine trophoblast protein-1 (bovine trophoblast interferon).

Bovine trophoblast protein-1 (bTP-1) is a 172-amino acid interferon- alpha that has a role in maternal recognition of pregnancy in cattle. Here we describe production of bTP-1 by recombinant procedures in Escherichia coli. A bTP-1 gene was constructed which lacked the codons representing the signal sequence and provided a Met initiation codon ahead of the TGT codon encoding Cys1 of the mature protein. This construct was placed under the control of the Trp promoter within the expression vector pTrp2. Expression occurred optimally in E. coli D112 in the absence of tryptophan and in the presence of 0.5% acid-hydrolyzed casein (casamino acids) when 0.5 mM indole acetic acid was included in the medium. The bTP-1 was deposited in inclusion bodies and accounted for as much as 27% of the total cellular protein. The inclusion bodies were isolated by differential centrifugation and washed. The bTP-1 was solubilized by use of guanidinium-HCI and 2-mercaptoethanol and allowed to renature in air. Final purification was achieved by anion exchange chromatography on DEAE-cellulose. The yield of purified product, which had an antiviral activity greater than 10(8) international reference units/mg, was approximately 20 mg/liter. The recombinant bTP-1 was relatively stable to freeze-thawing and frozen storage, and could induce the production of an acidic protein of 70,000 mol wt in cultured explants of endometrium prepared from ewes on day 13 of the estrous cycle. The latter protein is a characteristic product of interferon-alpha action on uterine tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Mineral and trace element content of human transitory milk indentified with inductively coupled plasma atomic emission spectrometry.

Mineral and trace element content of the human transitory milk collected on days 6 to 9 postpartum in Tokyo was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). Ten elements (Na, Mg, P, S, K, Ca, Fe, Cu, Zn, and Sr) were detected in ten-fold diluted milk sample with this method. With the stepwise multiple regression analysis, maternal and infants' biological attributes, such as weight, stature, sex, or age, were noted as factors contributing to the interindividual variation in Na, Mg, P, S, and Sr. Biological mechanism responsible for this selection cannot be found. Days postpartum for the milk collection was selected as a highly significant (p less than 0.001) variable with negative coefficient to explain milk S variation.

Adult↗
PubMed1990

[Cyclocryotherapy in the treatment of glaucoma].

33 patients (37 eyes) of neovascular and non-neovascular glaucoma were treated with cyclocryotherapy and followed up for 3-67 months, averaging 25 months. The IOP was brought under 2.73 kPa (21 mmHg) in 57.1% of the neovascular and 33.3% of the non-neovascular glaucomatous eyes, with an overall average IOP drop of 3.07 kPa (23.1 mmHg). Pain was controlled in 86.7% of the eyes. Cyclocryotherapy appeared to be an effective procedure for cases of refractory glaucoma, particularly those of neovascular origin. The complications and their mechanism were also discussed.

Adolescent↗
PubMed1989

Electron microscopic study of platelet agglutination induced by thrombotic thrombocytopenic purpura plasma containing 37-KDa platelet agglutinating protein.

It has been demonstrated that plasma from a patient with thrombotic thrombocytopenic purpura (TTP) and 37-KDa platelet-agglutinating protein (PAP p37) purified from the same plasma caused the agglutination of platelets from normal subjects as well as from the same patient after recovery without the requirement of extracellular Ca++ and fibrinogen. Experiments were designed to study the morphologic changes of platelets as a result of agglutination and the distribution of platelet receptors for PAP p37 under transmission electron microscope. Following incubation with TTP plasma or PAP p37 with stirring, platelets showed shape change, pseudopod formation, variable degrees of degranulation, dilatation of open canalicular systems and formation of agglutinates composed of a few to several hundred platelets. After platelets were incubated with TTP plasma or PAP p37 they were washed and further incubated with rabbit anti-PAP p37 serum without stirring followed by immuno-staining. Abundant electron dense reaction products were bound directly and randomly to the outer surface of the membrane of solitary platelets. When the reaction mixture was stirred, electron dense particles were also present between the platelet membranes in the agglutinates. No staining was observed in control experiments using normal plasma or non-immune rabbit serum. These results indicate that the TTP plasma containing PAP p37 causes agglutination, shape change, and variable degrees degranulation in platelets and that PAP p37 binds randomly to the outer surface of platelet membrane.

Blood Platelets↗