Biomedical subjects

D Jin

Publications and source records attributed to D Jin.

At least 55 records · Page 3Linked to original sources

PubMed1999

Effects of daphnodorin A, daphnodorin B and daphnodorin C on human chymase-dependent angiotensin II formation.

We investigated whether daphnodorin A, daphnodorin B and daphnodorin C inhibited human chymase-dependent angiotensin II-forming activity. Although the structures of these compounds are very similar, daphnodorin A completely inhibited angiotensin II formation generated by chymase, while daphnodorin B partially inhibited and daphnodorin C did not. On the other hand, these daphnodorins did not affect angiotensin converting enzyme-dependent angiotensin II formation. Furthermore, these daphnodorins did not inhibit purified human tryptase, which, like chymase, is contained in mast cells. Therefore, daphnodorin A, but not daphnodorin B and daphnodorin C, may specifically inhibit the chymase-dependent angiotensin II formation, and such differences between inhibitory effects of these compounds to human chymase may be useful for the development of human chymase inhibitor.

Adult↗

PubMed1999

Effects of a new 12-lipoxygenase inhibitor, daphnodorin A, on angiotensin II-induced vascular contraction in hamster.

We studied whether lipoxygenase inhibition suppressed angiotensin II-induced vascular contraction. In the present study, we used a new 12-lipoxygenase inhibitor, daphnodorin A, and an analogue of daphnodorin A, daphnodorin B, which has no inhibitory effects on 12-lipoxygenase. Daphnodorin A at 30 microM and 100 microM significantly suppressed the contractile responses induced by angiotensin 11 (3 x 10(-8) M) in isolated hamster aorta, while daphnodorin B up to 100 microM did not affect the responses. These results suggest that daphnodorin A, but not daphnodorin B, may suppress angiotensin II-induced vascular contractile responses through the inhibition of 12-lipoxygenase.

Angiotensin II↗

PubMed1999

[Pathophysiological roles of chymase and effects of chymase inhibitor].

Human chymase forms angiotenin (ANG) I to ANG II, whereas the roles of ANG II generated by chymase and the effects of chymase inhibitors have been unclear. On the other hand, rat chymase could not convert ANG I to ANG II. In isolated rat arteries, the ANG I-induced vascular contraction was completely suppressed by angiotensin-converting enzyme (ACE) inhibitor only. However, 30% of ANG I-induced vascular contraction in isolated human arteries was suppressed by an ACE inhibitor, but the remainder was blocked by chymostatin. In hamster hypertensive models, ANG II formation by ACE, but not by chymase, in vascular tissues plays an important role in maintaining hypertension. ANG II formation also induces vascular remodeling such as neointima formation. After balloon injury of vessels in dog, chymase and ACE activities were significantly increased in the injured vessels. In this model, an ANG II receptor antagonist was effective in preventing neointimal formation after balloon injury of vessels in dog, but an ACE inhibitor was ineffective. In dog grafted veins, the activities of chymase and ACEmin the grafted vein were significantly increased 15- and 2-fold, respectively, compared with those in the symmetrical veins. The intimal area of the grafted vein was reduced by a chymase inhibitor. Therefore, chymase-dependent ANG II formation plays an important role in the proliferative response, and chymase inhibitors may appear useful for preventing vascular proliferation.

Angiotensin I↗

PubMed1999

Effects of a lipoxygenase inhibitor, panaxynol, on vascular contraction induced by angiotensin II.

We investigated whether a lipoxygenase inhibitor, panaxynol, affected the vascular contraction induced by angiotensin (Ang) II and the mean arterial pressure in spontaneously hypertensive rats (SHR). Panaxynol suppressed dose-dependently the contractile responses induced by 30 nM Ang II in isolated intact and endothelial cell-denuded aorta in the hamster. IC50 values in the intact and endothelial cell-denuded aorta were 23 and 20 microM, respectively. In SHR, the mean arterial pressure after injection of 30 and 60 mg/kg panaxynol was reduced, and the maximum hypotensive values were 23 and 48 mmHg, respectively. Thus, lipoxygenase products may affect the renin-angiotensin system.

Alkynes↗

PubMed1999

[The effects of platelet-derived growth factor on rat osteoblastic DNA contents].

OBJECTIVE: To study the effects of platelet-derived growth factor (PDGF) on the DNA content of the isolated osteoblast-like cells and the cellular period changes, and further study the effect of PDGF on bone fracture healing. METHODS: The cultured osteoblast-like cells in vitro were isolated from fetal rat calvaria and the effects of PDGF on cellular DNA contents were observed under flow cytometer. The changes of osteoblastic surface structure and ultrastructure were observed under electron microscope. RESULTS: PDGF could increase the DNA contents of cellular S period by promoting osteoblast from G0/G1 period into S period. The effects of PDGF on increasing cellular DNA contents were most significant at 24th culture hour (DNA content: 17.6% at the 24th hour, 9.0% at the 48th hour, 10.2% at the 72nd hour). PDGF could increase osteoblastic surface granules, reticular fibers and intracellular calcium salt crystals, and calcium granule mitochondria. CONCLUSIONS: PDGF could promote bone fracture healing by stimulating osteoblastic DNA synthesis and cell proliferation. The flow cytometer is a better instrument to analyze cell DNA content for a large number of cells.

Animals↗

PubMed1999

[Nosocomial catheter-related sepsis secondary to central venous catheters].

OBJECTIVE: To study bacteria and drug sensitivity of catheter-related sepsis (CRS). METHODS: Between February 1993 and December 1997, 52 patients with central venous catheter-related sepsis were studied retrospectively. RESULTS: The most common organisms were staphylococcus aureus and staphylococcus epidermis. The bacterial pathogens isolated demonstrated a marked pattern of antibiotic resistance. Gram-positive cocci were sensitive to vancomycin with a sensitivity of 93.3%, and gram-negative bacilli were sensitive to amikacin and ceftazidine with a sensitivity of 51.7%. CONCLUSIONS: The effective treatment of catheter-related sepsis is removal of infected catheters. Vancomycin and (or) amikacin may be first chosen to treat CRS.

Amikacin↗

PubMed1999

[An analysis of nutritional and harmful components of vegetables grown in plastic greenhouses].

OBJECTIVE: To study the changes in nutritional and harmful components of vegetables grown in plastic greenhouses. METHODS: In plastic greenhouses, microclimate and air concentrations of carbon monoxide, carbon dioxide, fluoride and respirable particulate were measured, and chlorophyll, total sugar, crude fiber, nitrite, fluoride, arsenic and some mineral elements in vegetables were determined as compared with those grown in the open-air fields. RESULTS: Greenhouse appeared a lower wind speed and darker illumination. Contents of chlorophyll a an b, total chlorophyll, reduced vitamin C, crude fiber in vegetables grown in greenhouse all were lower than those grown in open-air fields. Contents of potassium, calcium, magnesium, iron, zinc, copper and phosphorous were all lower in the vegetables grown in greenhouse than those grown in open-air fields. The contents of chlorophyll reducing Vitamin C. CONCLUSION: Lower wind speed and inadequate illumination in greenhouse affected photosynthesis and uptake of water in vegetables causing changes in their nutritional components. But, no contamination of burning coal was found in vegetables grown in greenhouse.

Air Pollutants↗

PubMed1999

[Human motion analysis system based on common video-camera].

A new human motion analysis system based on common video-camera is introduced in this paper. The image processing technique is used to recognize and track anatomic landmarks, which makes data processing more quickly and accurately. The system is cost-effective and can be easily operated because the common video-cameras instead of special instruments are used. Furthermore, the system can also be used for detection and analysis of other low-speed moving objects.

Algorithms↗

PubMed1999

[Application study of yangkang biological fertilizer on Panax notoginseng cultivation].

Yangkang Biological Fertilizer was sprayed on Panax notoginseng. The result indicated that the yield and the surviving rate can be raised 25.2% and 15.2% respectively. The best spraying practice were: in the unfolding stage of leaves (April) and bloom stage (July), with Yangkang Biological Fertilizer plus water (1:400), at four times every stage.

Fertilizers↗

PubMed1998

Tranilast, an anti-allergic drug, possesses antagonistic potency to angiotensin II.

N-(3',4'-dimethoxycinnamoyl) anthranilic acid (tranilast), an effective anti-allergic drug, has successfully prevented restenosis in patients who have undergone percutaneous transluminal coronary angioplasty. To elucidate the mechanism of tranilast, we investigated its antagonistic effect to angiotensin II, which plays a pivotal role in the proliferation of vascular smooth muscle cells, using angiotensin II-induced contractions in human gastroepiploic artery and rabbit aorta. The possible antagonistic effects of other anti-allergic agents such as 4-( p-chlorobenzyl)-2-(hexahydro-1-methyl-1H-azepin-4-yl)-1(2H)-phthal azinone hydrochloride (azelastine), 9-methyl-3-( 1H-tetrazol-5-yl)-4H-pyrido[1,2-a]pyramidin-4-one potassium salt (pemirolast) and disodium cromoglycate were also compared. Tranilast dose-dependently inhibited the angiotensin II-induced contractions in human and rabbit arteries (IC50 = 3.6x10(-5) M and pD'2 = 3.69, respectively). Pemirolast showed a weak antagonistic effect to angiotensin II, but the effective concentration cannot be administered in clinical dosage. Tranilast and pemirolast had no effect on the concentration-contractile response curves for KCI and norepinephrine. Azelastine inhibited angiotensin II-, KCl- and norepinephrine-induced contractions non-specifically, while disodium cromoglycate did not affect these contractile responses. Tranilast but not azelastine showed synergistic action with 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-benzimi dazole-7-carboxylic acid (CV- 11974) in antagonizing angiotensin II-induced contraction and the inhibitory pattern was similar to that of the non-peptide angiotensin II AT1 receptor antagonist CV-11974. These findings indicate that only tranilast possesses the unique ability to antagonize angiotensin II in clinical dosage, which may contribute at least in part to prevention of restenosis after percutaneous transluminal coronary angioplasty.

Adrenergic alpha-Agonists↗

PubMed1998

Platelet-derived growth factor (PDGF)-BB stimulates osteoclastic bone resorption directly: the role of receptor beta.

The growth-promoting activity of PDGF-BB was studied on the adult osteoclasts in the present study. The PDGF receptor beta was detected on the osteoclast membrane through immunohistochemistry (LSAB method) and immunomicroscopy. The PDGF-BB was exerted on the osteoclasts that adhered to the bone slice at concentrations of 0, 10, 20, 30, and 40 ng/ml. The volume of Howship's lacuna augmented significantly and the number of resorption pits also increased with its dose (p < 0.01). The activity of both total acid phosphatase (ACP) and tartrate-resistant acid phosphatase (TRAP) increased significantly. These results suggest that PDGF-BB promotes adult osteoclastic bone resorption directly through PDGF receptor beta and is believed to play important roles in the bone healing process and reconstruction.

Acid Phosphatase↗

PubMed1998

Chymase processes big-endothelin-2 to endothelin-2-(1-31) that induces contractile responses in the isolated monkey trachea.

Purified monkey chymase cleaved the Tyr31-Gly32 bond of big-endothelin-1 and big-endothelin-2 to yield endothelin-1-(1-31) and endothelin-2-(1-31), respectively. In the isolated monkey trachea, endothelin-1-(1-31) and endothelin-2-(1-31), as well as big-endothelin-1 and big-endothelin-2, induced contractile responses. Chymostatin, which inhibits chymase, suppressed the contractile response induced by big-endothelin-2 to 16.6% but not the responses induced by big-endothelin-1, endothelin-1-(1-31) and endothelin-2-(1-31). These results suggest that the contractile response of big-endothelin-2 is predominantly dependent on the conversion of big-endothelin-2 to endothelin-2-(1-31) by chymase.

Animals↗

PubMed1998

12-Hydroxyeicosatetraenoic acid directly potentiates angiotensin II-induced vascular contraction.

We studied whether 12-hydroxyeicosatetraenoic acid (HETE) affected the angiotensin II-induced contractile response in isolated hamster aorta. After preincubation with 10 nM 12-HETE for 1, 3, 5, 10 and 30 min, the angiotensin II-induced contractions were increased to 101%, 109%, 114%, 109% and 98%, respectively. The optimum preincubation time for the maximum effect of 12-HETE was 5 min. Under these conditions, 12-HETE increased dose dependently the contraction induced by 10 nM angiotensin II, and the concentration needed for the maximum effect was 30 nM, which increased contraction to 118% compared to the control angiotensin II-induced contraction. We demonstrated clearly that 12-HETE directly potentiates the angiotensin II-induced contraction.

Angiotensin II↗

PubMed1998

Total resolution of 17 DL-amino acids labelled with a fluorescent chiral reagent, R(-)-4-(3-isothiocyanatopyrrolidin-1-y1)-7-(N,N-dimethylaminosulfonyl)- 2,1,3-benzoxadiazole, by high-performance liquid chromatography.

Total resolution of 17 DL-amino acids after derivatization with a fluorescent chiral tagging reagent, 4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfony l)-2,1,3- benzoxadiazole [R(-)-DBD-PyNCS], was studied by reversed-phase liquid chromatography. The reaction of the reagent with amino acids proceeds effectively at 55 degrees C for 20 min in the presence of 1% TEA to produce the corresponding fluorescent diastereomers (excitation at 460 nm, emission at 550 nm). Each pair of the resulting derivatives was efficiently separated with water-acetonitrile containing 1% acetic acid as the mobile phase. Peak resolution was in the range of 0.92 (DL-Arg)-9.8 (DL-Cys). Although mutual separation of some DL-amino acids was possible using the elution solvent, simultaneous resolution of 17 DL-amino acids was difficult with a single chromatographic run, even if some gradient elutions were adopted. Therefore, both gradient and isocratic elution systems were used for total resolution of the DL-amino acids. Thus, 17 DL-amino acids were well resolved by a gradient and an isocratic elution systems. The proposed derivatization and elution methods were applied to the determination of DL-amino acids in yogurt. The results showed that some of the L-amino acids, i.e., Glu, Asp, Ser, Gly, Ala, Thr, Pro, Lys, Phe and Met, were found in the methanol extracts of yogurt. On the other hand, the D-amino acids that were identified in the extracts were D-Glu, D-Asp and D-Ala, and the mean % to each L-amino acid were 11.9% (D-Glu), 27.6% (D-Asp) and 56.7% (D-Ala), respectively.

Amino Acids↗

PubMed1998

Osteogenic protein-1 (bone morphogenetic protein-7) reduces severity of injury after ischemic acute renal failure in rat.

We have shown that osteogenic protein-1 (OP-1) (bone morphogenetic protein-7) is responsible for the induction of nephrogenic mesenchyme during embryonic kidney development. Gene knock-out studies showed that OP-1 null mutant mice die of renal failure within the first day of postnatal life. In the present study, we evaluated the effect of recombinant human OP-1 for the treatment of acute renal failure after 60 min bilateral renal artery occlusion in rats. Bioavailability studies in normal rats indicate that approximately 1.4 microg OP-1/ml is available in the circulation 1 min after intravenous administration of 250 microg/kg, which then declines steadily with a half life of 30 min. About 0.5% of the administered OP-1 dose/g tissue is targeted for OP-1 receptors in the kidney. We show that OP-1 preserves kidney function, as determined by reduced blood urea nitrogen and serum creatinine, and increased survival rate when administered 10 min before or 1 or 16 h after ischemia, and then at 24-h intervals up to 72 h after reperfusion. Histochemical and molecular analyses demonstrate that OP-1: (a) minimizes infarction and cell necrosis, and decreases the number of plugged tubules; (b) suppresses inflammation by downregulating the expression of intercellular adhesive molecule, and prevents the accumulation and activity of neutrophils; (c) maintains the expression of the vascular smooth muscle cell phenotype in pericellular capillaries; and (d) reduces programmed cell death during the recovery. Collectively, these data suggest that OP-1 prevents the loss of kidney function associated with ischemic injury and may provide a basis for the treatment of acute renal failure.

Acute Kidney Injury↗

PubMed1998

Propagation of experimental uncertainties using the Lipari-Szabo model-free analysis of protein dynamics.

In this paper we make use of the graphical procedure previously described [Jin, D. et al. (1997) J. Am. Chem. Soc., 119, 6923-6924] to analyze NMR relaxation data using the Lipari-Szabo model-free formalism. The graphical approach is advantageous in that it allows the direct visualization of the experimental uncertainties in the motional parameter space. Some general 'rules' describing the relationship between the precision of the relaxation measurements and the precision of the model-free parameters and how this relationship changes with the overall tumbling time (tau m) are summarized. The effect of the precision in the relaxation measurements on the detection of internal motions not close to the extreme narrowing limit is analyzed. We also show that multiple timescale internal motions may be obscured by experimental uncertainty, and that the collection of relaxation data at very high field strength can improve the ability to detect such deviations from the simple Lipari-Szabo model.

Models, Theoretical↗

PubMed1998

Roles of vascular angiotensin converting enzyme and chymase in two-kidney, one clip hypertensive hamsters.

BACKGROUND: A chymase-dependent angiotensin II-forming pathway is present in human vascular tissues; however, the role, if it plays any, of chymase in the pathogenesis of hypertension is not known. When investigating the role of chymase, it is important to recognize marked differences in vascular angiotensin II-forming systems among species. We found recently that hamsters, like humans, possess the dual angiotensin II-forming system. OBJECTIVE: To analyze the potential involvement of angiotensin converting enzyme and chymase in the pathogenesis of hypertension, and to further characterize the efficiency of angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists for the treatment of hypertension. METHODS AND RESULTS: The mean arterial pressure in the two-kidney, one clip hamster model had increased significantly 2 weeks after clipping (acute stage), reached a peak after 4 weeks, and was sustained at the high level until 32 weeks after clipping (chronic stage). Plasma renin activity increased markedly during the acute stage, but returned to the normal level during the chronic stage. Vascular angiotensin converting enzyme activity during 4-32 weeks after clipping was significantly higher than that in the control hamsters. By contrast, vascular chymase was not activated throughout the experimental period. Administrations of an angiotensin converting enzyme inhibitor, trandolapril, and an angiotensin II receptor antagonist, CV-11974, equally lowered the mean arterial pressure during the acute and chronic stages. CONCLUSIONS: Vascular angiotensin converting enzyme plays a predominant role in the maintenance of two-kidney, one clip hypertension in hamsters, which, like humans, possess a dual system of formation of angiotensin II. Vascular chymase was not involved in the pathogenesis of two-kidney, one clip hypertension in the hamster.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1998

Functional role of chymase in angiotensin II formation in human vascular tissue.

Recent reports suggested that human heart chymase contributed little to angiotensin (Ang) II formation in the presence of natural protease inhibitors such as alpha-antitrypsin. We studied whether chymase could contribute to Ang II formation in the presence of natural protease inhibitors in the homogenate, the extract, and slices of human vascular tissue, and whether these inhibitors affect Ang I-induced vasocontractile responses due to chymase. In the homogenate, lisinopril, chymostatin, and alpha-antitrypsin inhibited the formation of Ang II by 14, 92, and 74%, respectively. In the extract, the inhibition of Ang II formation by lisinopril, chymostatin, and alpha-antitrypsin was 18, 94, and 93%, respectively. In the slices, lisinopril and chymostatin inhibited Ang II formation by 5 and 90%, respectively. However, unlike the homogenate and the extract experiments, only 8% of the Ang II formation was suppressed by alpha-antitrypsin. In isolated human gastroepiploic artery, 30% of Ang I-induced vasoconstriction was blocked by lisinopril, and the rest was completely eliminated by a combination of lisinopril and chymostatin. On the other hand, alpha-antitrypsin was ineffective in blocking Ang I-induced vasoconstriction in the presence of lisinopril, which demonstrates that Ang II formation is dependent on chymase. These findings suggest that chymase in human vascular tissue plays a functional role in Ang II formation in the presence of natural protease inhibitors such as alpha-antitrypsin.

Angiotensin I↗