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Biomedical subjects

H M Jin

Publications and source records attributed to H M Jin.

At least 19 recordsLinked to original sources
PubMed2000

Dysfunction of microvascular endothelial cells induced by tumor necrosis factor (TNFalpha): cellular and molecular mechanism.

The dysfunction of rat pulmonary microvascular endothelial cells (RPMVEC) induced by tumor necrosis factor alpha (TNFalpha) was investigated in cell culture. The TNFalpha concentrations added into culture were 1000-5000 u/ml. The study was done at different steps as follows: (1) cell proliferation dynamic, (2) coagulation and anti-coagulation, (3) adhesive molecule, (4) nitric oxide (NO), (5) oncogens, and (6) apoptosis. It was concluded that attention should be paid to the metabolic disorder and dysfunction of RPMVEC induced by TNFalpha which can not be found easily according to the morphological changes. This might be the common pathway in the pathogenesis of some diseases related to TNFalpha.

Animals↗
PubMed1999

Effects of commercial glucose-based peritoneal dialysates on peripheral blood phagocytes apoptosis.

BACKGROUND: Variable glucose-lactate-based peritoneal dialysates have negative effects on peritoneal macrophages and peripheral blood leukocytes, reducing the capacity of leukocytes for chemotaxis, bacterial killing. But few reports exist on cell apoptosis. To investigate the effects of glucose-lactate-based peritoneal dialysates on cultured phagocytes (monocytes and neutrophils), we focused on studying phagocyte apoptosis after brief exposure to commercial peritoneal dialysates. METHODS: Cell apoptosis is measured by flow cytometry (FCM) to detect phosphatidylserine (PS) exposure on early apoptotic cells using fluorescein-labeled annexin V. To mimic the composition of dialysate in vivo, where the freshly instilled solution mixes with the residual dialysate from the previous cycle, we performed the experiments using a mixture of fresh and spent dialysate (9:1). In our transient exposure experiments, monocytes and neutrophils were separately incubated in each of the test solutions (1.5% glucose and 4.25% glucose dialysates) for 10 minutes or 30 minutes and afterward separated and resuspended in RPMI 1640 medium and cultured over the indicated time. RESULTS: After exposure to 1.5% glucose dialysates for 10 minutes, monocytes and neutrophils exhibited normally spontaneous apoptosis. After exposure to 4.25% glucose dialysate, monocytes underwent apoptosis increasingly, 21%+/-5.0% versus 9.8%+/-3.6% (p < 0.05) at 24 hours and 47%+/-6.2% versus 16%+/-4.0% (p < 0.01) at 72 hours compared with controls. For neutrophils, the results were discouraging: hypertonic dialysate not only increased apoptosis [65.36%+/-2.6% versus 34.17% +/-8.52% (p < 0.01) at 72 hours], but also induced cell necrosis. When Incubation time was prolonged for 30 minutes, 1.5% dialysate acted like 4.25% dialysate, with the rate of apoptosis increasing rapidly [40%+/-4.0% versus 16%+/-4.0% (p < 0.01) at 72 hours for monocytes, and 66.90%+/-5.6% versus 34.17%+/-8.52% (p < 0.01) at 72 hours for neutrophils]. CONCLUSION: Glucose-lactate-based peritoneal dialysates can induce peripheral blood phagocyte apoptosis in vitro, which indicates that glucose plays an important role in triggering cell apoptosis. Therefore, looking for new, physiologic peritoneal dialysis fluids to replace conventional fluids is reasonable.

Annexin A5↗
PubMed1999

[Reduction of mitochondrial transmembrane potential constitutes an early event of peripheral blood monocytes apoptosis in hemodialysis patients].

OBJECTIVE: To investigate the relationship between monocyte apoptosis and mitochondria function in hemodialysis (HD) patients. METHODS: Fluorescein labeled Annexin-V was used to detect the phosphatidyserine (PS) of apoptosis cells, and mitochondrial transmembrane potential was studied by 3,3'-dihexyloxacarbocyanine iodide, Di0C6(3), and analyzed by flow cytometry. Swelling of mitochondrial permeability transition (PT) was recorded by spectrophotometer. RESULTS: Spontaneous apoptosis of cultured monocytes increased at 24, 72 hours in HD patients (41.4 +/- 12.2)%, (22.0 +/- 3.0)% as compared with controls (20.6 +/- 8.8)%, (9.8 +/- 2.1)%. Freshly isolated monocytes in HD patients had little apoptosis, but mitochondrial transmembrane potential was reduced to half of disruption (43 +/- 9)%. As to swelling of PT, those freshly isolated monocytes mitochondria in HD patients experienced overwhelming opening of PT, (80 +/- 5.6)%. CONCLUSION: Swelling of PT and breakdown of mitochondrial transmembrane potential constitute the early events of monocytes apoptosis in HD patients, which could contribute to the impaired monocytes function.

Adult↗
PubMed1998

Genetic characterization of the murine Ym1 gene and identification of a cluster of highly homologous genes.

The murine Ym1 gene belongs to a family of mammalian genes that are homologous to the chitinases from lower organisms, such as insects, nematodes, bacteria, and plants. All of these homologous mammalian proteins (except one member) have no demonstrable chitinase activity and therefore cannot be considered chitinases. The biological functions of these proteins remain unknown. However, these proteins may function through binding to carbohydrate polymers. In an effort to characterize the murine Ym1 gene better, we have delineated its genomic structure. We mapped the chromosomal location of the Ym1 gene to a central region of mouse chromosome 3 (in the region syntenic to human chromosome 1p13) and that of another murine chitinase-like gene, Brp39, to a central region of mouse chromosome 1 (in the region syntenic to human chromosome 1q31). In addition, we identified several genes highly homologous to Ym1 that cluster at the Ym1 locus. We show that these genes are expressed selectively in different mouse tissues.

Amino Acid Sequence↗
PubMed1997

Strategies for the in vitro evolution of protein function: enzyme evolution by random recombination of improved sequences.

Sets of genes improved by directed evolution can be recombined in vitro to produce further improvements in protein function. Recombination is particularly useful when improved sequences are available; costs of generating such sequences, however, must be weighed against the costs of further evolution by sequential random mutagenesis. Four genes encoding para-nitrobenzyl (pNB) esterase variants exhibiting enhanced activity were recombined in two cycles of high-fidelity DNA shuffling and screening. Genes encoding enzymes exhibiting further improvements in activity were analyzed in order to elucidate evolutionary processes at the DNA level and begin to provide an experimental basis for choosing in vitro evolution strategies and setting key parameters for recombination. DNA sequencing of improved variants from the two rounds of DNA shuffling confirmed important features of the recombination process: rapid fixation and accumulation of beneficial mutations from multiple parent sequences as well as removal of silent and deleterious mutations. The five to sixfold further enhancement of total activity towards the para-nitrophenyl (pNP) ester of loracarbef was obtained through recombination of mutations from several parent sequences as well as new point mutations. Computer simulations of recombination and screening illustrate the trade-offs between recombining fewer parent sequences (in order to reduce screening requirements) and lowering the potential for further evolution. Search strategies which may substantially reduce screening requirements in certain situations are described.

Carboxylic Ester Hydrolases↗
PubMed1996

Experimental study on microthrombi and myocardial injuries.

The experiment was conducted with SD male rats. After they had been each given an intravenous injection of high molecular weight dextran (0.8 ml/100 g body wt) once a day for 4 days, they were brought under the observation of ECG and mesentery microcirculation. Microthrombi were found in the venules and capillaries of each rat of the experimental group, while in the microcirculation of the control group rats, no microthrombi were found. No changes were found in the ECGs of the rats (n = 6) in the control group after the injections, while the rats in the subject group all suffered a rise in the S-T segment of ECG, an indication of myocardial injuries. The rise was significantly in positive correlation to the increase in microthrombi in number (r = 0.944, P < 0.01). The erythrocytes of the rats in the subject group clustered to become rouleau-like, and platelets aggregated by tens and hundreds to form microthrombi. Their blood also showed a significant decrease in number of platelets. The degree of platelet aggregation and the scores of the rise on ECG were significantly in positive correlation as shown by the results: y = 20 + 94x, r = 0.94, P < 0.01. The plasma TXB2 of the subject group increased obviously but the change of 6-K-PGF1 alpha in the blood was not significant. The content of plasma TXB2 and the scores that indicated the rise in the S-T segment of the ECG showed significantly a positive correlation by the analysis of linear regression equation: y = 109.997 +/- 116.25x, r = 0.889, P < 0.05. The activity of Na(+)-K(+)-ATPase on the myocardial cell membranes of the rats with microthrombi was significantly reduced as compared with that of the rats in the control group (P < 0.01). The activity of the Na(+)-K(+)-ATPase was significantly in negative correlation to the rise in the S-T segment of ECG (P < 0.05). This study demonstrates that the above changes are the causes of myocardial injuries in rats with circulatory thrombi.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

SIS/PDGF-B promoter isolation and characterization of regulatory elements necessary for basal expression of the SIS/PDGF-B gene in U2-OS osteosarcoma cells.

Platelet-derived growth factor BB, encoded by the SIS/PDGF-B gene, is a potent mitogen for cells of mesenchymal origin, and the SIS/PDGF-B gene is expressed in a large percentage of human mesenchymal tumor cells establishing a growth-promoting, autocrine growth circuit. A 4-kb fragment, containing the SIS/PDGF-B promoter, was isolated from a human genomic library, and a series of 5'-nested deletions and linker-scanning mutants were used to identify positive regulatory elements that are necessary for the constitutive expression of this gene in human U2-OS osteosarcoma cells. A 250-bp fragment, lying immediately 5' to the SIS/PDGF-B mRNA initiation site (+1), retained full promoter activity, and positive regulatory elements at -228 to -219, -97 to -88 (SIS distal element) and -58 to -39 (SIS proximal element, SPE) were identified. Insertion of the 20-bp SPE into a heterologous, minimal promoter resulted in >5-fold transcriptional activation which was ablated by mutations to the SPE. High resolution mutagenesis within the 20-bp SPE, indicated the necessity of a CACCC motif for activity. Gel shift analysis of SPE-binding proteins in U2-OS nuclear extracts identified Sp1 and two additional binding factors that could be competed away from SPE binding by adding excess consensus Sp1 or CACC oligonucleotides. The individual and aggregate roles of the SPE and two weaker positive regulatory elements in regulating SIS/PDGF-B transcription in these tumor cells is considered.

Base Sequence↗
PubMed1994

[Treatment of pediatric late stage neuroblastoma].

From 1960 to 1992, 62 children with late stage neuroblastoma (stage III-IV) were admitted to our hospital. 24 (1960-1982) treated with operation and routine chemotherapy all died in 24 months after operation. And in 38 (1983-1993) treated with operation and high dose chemotherapy (including auto-bone-marrow transplantation + three times dose VM26 + routine chemotherapy in 3 cases, high dose chemotherapy + resection of tumor + high dose chemotherapy + routine chemotherapy for 4 years in 27, and dumbbell neuroblastoma in 8), 24 cases (63.%) still lived up to now. In which 11 cases (28.9%) lived more than 5 years and other 13 cases middle survival stage was 26.9 months. The high chemotherapy couldn't be instead of operation but it might produce a favourable condition to radical operation and thereby increase the effect of the operation.

Antineoplastic Agents↗
PubMed1994

[Effect of jiang-zhi jian-fei yao on gastro-intestinal movement and adipose cell of abdominal wall].

Jiang-Zhi Jian-Fei Yao (JZJFY), an obesity-reducing drug, its active principle is the refined Rhubarb, the mechanism of its obesity-reducing effect was studied. JZJFY was injected intragastrically. The results showed that there was no significant increased of body weight, but a reduction of food intake, prolongation of stomach evacuation time, acceleration of intestinal movement 6 days after medication in rats. Meanwhile the adipose cells in abdominal wall were varied in size, and with Sudan III stain the color of adipose cells was light. Authors suggest that the obesity-reducing effect of JZJFY was relevant to above-mentioned changes.

Adipocytes↗
PubMed1993

Identification and characterization of an essential, activating regulatory element of the human SIS/PDGFB promoter in human megakaryocytes.

The SIS/PDGFB gene, encoding the B polypeptide of platelet-derived growth factor (PDGF-B), is transcriptionally activated (> 50 fold) in human K562 erythroleukemia cells when they are induced to differentiate into megakaryocytic cells by treatment with phorbol 12-myristate 13-acetate ("tetradecanoylphorbol acetate," TPA). A 250-bp PDGF-B gene promoter attached to a reporter gene was shown to reproduce this TPA-induced activation. In a series of mutants that we constructed, a 10-bp linker sequence was systematically moved across the 250-bp PDGF-B promoter sequence, and the effect upon luciferase reporter activity was measured to identify a site through which this TPA-induced transcriptional activation occurred. We identified a site, which we named the SIS proximal element (SPE), at positions -58 to -39 relative to the PDGF-B mRNA initiation site that was essential for the TPA-induced activation. The SPE site contains two repeated sequences (TCTC and CACC) arranged in an ABBA configuration. The SPE sequence was not found in the existing list of consensus sequences for transcription factor binding sites. Gel mobility-shift assays using an SPE oligonucleotide and K562 cell nuclear extracts showed three shifted complexes, one of which was formed only following TPA treatment of K562 cells. In a time-course study, TPA induction of the endogenous PDGF-B mRNA and formation of the TPA-inducible complex occurred over the same time frame, and both events were specifically blocked by the addition of cycloheximide. The 20-bp SPE sequence was highly conserved (19/20) in both the cat and the mouse PDGF-B promoter, and conserved portions of the SPE sequence were also found at two sites within the human PDGF-A promoter. The role of the SPE in regulating the concurrent expression of the PDGF-B and PDGF-A genes in megakaryocytes, as well as various human tumor cells, is considered.

Animals↗
PubMed1993

[Control of retrograde urethrocystitis by converted Y-type urethral catheter].

A converted Y-type urethral catheter was used to curb retrograde urethrocystitis due to indwelling urethral catheter. Satisfactory results were obtained in 30 cases. Injection of 0.5% bromo-geramine (10 ml) into the bladder through the bypass tube killed effectively the bacteria in the indwelling catheter. The device had the functions of urine deposit, urine conduction, bladder and urethral washing as well as urine sample collection. The connection between indwelling urethral catheter and the conducting tube was not dismantled during the procedure. So it reduced the chance of extraneous contamination.

Catheters, Indwelling↗
PubMed1991

Incorporation of circulating fibronectin into various tissues during sepsis: colocalization with endogenous tissue fibronectin.

We studied the plasma clearance and tissue incorporation of intravenously infused purified human plasma fibronectin into various tissues during a period of acute lung vascular injury induced by lethal postoperative bacteremia in sheep. Lung, liver, spleen, and heart tissue were examined for both endogenous sheep tissue fibronectin as well as the experimentally infused human fibronectin using dual-label immunofluorescence. Awake sheep (n = 4) received a postoperative iv infusion of 5 x 10(9) live Pseudomonas over a 60-min infusion interval. Bacterial challenge was started 2 hr after starting the iv fibronectin infusion of purified human plasma fibronectin (100 mg iv bolus; 4 hr iv at 100 mg/hr). Human fibronectin displayed a biphasic rate of clearance from the plasma with entrance into lymph. Human fibronectin readily incorporated in all tissues studied, including the lung which was the focus of vascular injury. Analysis of tissue sections by dual-label immunofluorescence indicated that the exogenous human fibronectin colocalized with the endogenous sheep fibronectin. Thus, the plasma fibronectin concentration may influence the lung vascular barrier due to its incorporation into the tissue pool of fibronectin. Moreover, the plasma may serve as a reservoir for soluble fibronectin which can enter and colocalize with the insoluble tissue pool of fibronectin in various tissues.

Animals↗
PubMed1990

A study on content and distribution of plasma and tissue fibronectin in rats using ELISA and immunofluorescence.

The content of plasma fibronectin and tissue extractable fibronectin in normal rats was measured with rocket immunoelectrophoresis and ELISA in the present study. The difference in tissue fibronectin distribution in various organs and the correlation between distribution and content of fibronectin have been studied. We suggest that tissue fibronectin may be a complex component. The change in plasma fibronectin reflects a dynamic balance existing between the tissue fibronectin pool and plasma fibronectin pool in normal rats. Plasma fibronectin and tissue fibronectin concentrations are not static, and they can only be maintained in a relatively stable state in normal rats.

Animals↗
PubMed1989

[Research on the need to perform a second curettage of hydatidiform mole: analysis of 152 cases].

Curettage, for the second time, has been performed almost routinely for patients after the first curettage for hydatidiform mole. Is it necessary? The histopathologic results of the second curettage specimens were investigated. It showed that residual molar tissue was found in only 3.3% of the second curettage specimens. So in our opinion, a second curettage, which will not only add to patients' suffering but also would prolong hospitalization time, should be performed only in cases strongly indicated.

Dilatation and Curettage↗