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Biomedical subjects

C G Chen

Publications and source records attributed to C G Chen.

36 records · Page 2Linked to original sources
PubMed1989

Reliability of the Doppler pressure half-time method for assessing effects of percutaneous mitral balloon valvuloplasty.

The mitral valve areas determined by Doppler pressure half-time and by cardiac catheterization with use of the Gorlin formula were compared in 18 adult patients who underwent percutaneous mitral balloon valvuloplasty. Doppler measurements and catheterization were performed simultaneously before, immediately after and 24 to 48 h after valvuloplasty. A high correlation between Doppler- and catheterization-derived mitral valve areas was found before mitral valvuloplasty (r = 0.81, Y = 0.88X + 0.1, SEE = 0.11 cm2) and 24 to 48 h after valvuloplasty (r = 0.84, Y = 0.70X + 0.67, SEE = 0.20 cm2). In contrast, the correlation immediately after valvuloplasty was only moderate (r = 0.72, Y = 0.43X + 1.1, SEE = 0.49 cm2). The Doppler-derived mitral valve area (2.41 +/- 0.61 cm2) immediately after valvuloplasty was significantly larger than the catheterization-derived area (2.08 +/- 0.39 cm2, p less than 0.05). In conclusion, the Doppler echocardiographic measurement performed with the pressure half-time method may lead to significant error immediately after mitral balloon valvuloplasty, but clinically accurate measurement can be obtained 24 to 48 h after valvuloplasty.

Adult↗
PubMed1989

[Thrombolytic effect of a moderate dose of urokinase in acute myocardial infarction].

UNLABELLED: It appears that Chinese patients had more bleeding complications during anticoagulative and thrombolytic therapies than western populations. To determine the effect of a moderate dosage of urokinase for Chinese patients with evolving acute myocardial infarction (AMI), we studied 17 patients with AMI. The patients were divided into 2 groups: Urokinase group (UG) and control group (CG). Seven patients in UG, having AMI 5.1 +/- 1.3 hours after the onset received intravenous urokinase 250,000-450,000 units within 30 minutes and then were treated with heparin. Ten patients in CG, having AMI 12.1 +/- 10.1 hours after the onset received conventional therapy as well as heparin. The successful reperfusion of coronary artery was assessed noninvasively using peak CPK level less than 18 hours and elevated ST segment normalization within 24 hours as the criteria. RESULTS: Successful reperfusion was found in 5 of 7 patients in UG and in only 1 of 10 patients in CG (P less than 0.05). No gastrointestinal and cerebrovascular bleeding or other major bleeding complications were observed in UG, while 1 of 10 patients in CG had gastric bleeding requiring transfusion. The mortality during 2 months of hospitalization was 2/10 (20%) in CG, but no patient in UG died during 2 months of hospital stay. The results of the study suggest that moderate dosage of urokinase could achieve reperfusion in majority of Chinese patients with AMI and may have less bleeding complications. However, randomized and large-group patient studies are needed to confirm the presented results.

Adolescent↗
PubMed1988

Percutaneous mitral balloon dilatation by a new sequential single- and double-balloon technique.

Percutaneous balloon valvotomy by means of a new sequential single- and and double-balloon dilatation procedure was performed in 23 patients (aged 13 to 53 years) with severe rheumatic mitral stenosis. The dilatation procedure was initially performed with a small balloon to primarily dilate the stenotic valve for easier passage of a second balloon catheter and to make the procedure tolerable for severely ill patients; the procedure was then followed by two balloons to further increase the mitral valve area (MVA) for effective dilatation of the stenotic mitral orifice. The dilatation was successful in all patients; the mitral valve pressure gradient decreased from 19 +/ 6 to 5 +/ 2 mm Hg, the cardiac output increased from 4.0 +/ 0.5 to 5.2 +/ 0.6 L/min, and the MVA increased from 0.8 +/ 0.2 to 1.9 +/ 0.4 cm2 (p less than 0.01 each). The MVA after dilatation was relative to the effective balloon dilatation diameter selected (r = 0.57; p less 0.01). A small atrial septal defect was observed in 3 of 23 patients immediately after the dilatation procedure. Mild mitral regurgitation was produced in 3 of 23 patients by the dilatation. We conclude that the sequential single- and double-balloon dilatation procedure can effectively increase the MVA and improve hemodynamics in severe mitral stenosis and that the larger effective balloon diameter of 24.8 mm or more (12 +/ 18 mm of two balloons) is necessary for effective dilatation.

Adult↗
PubMed1986

Quantitative assessment of temporal and spatial ventricular wall motion in normal and infarcted human left ventricles.

A new integrated method for quantitating temporal and spatial systolic wall motion heterogeneity was developed and applied in 15 normal subjects and 26 patients with previous myocardial infarction (MI). After frame by frame digitizing, right anterior oblique left cineventriculograms (LV) were analyzed with 90 spaced radii. For each radius shortening fractions at sequential systolic time points relative to end diastole were correlated with corresponding normalized time points using linear regression method, yielding the radial correlation coefficient (r) and the radial regression slope (b) for temporal and spatial information. High radial r values with small standard deviations were observed in normal LV (0.972 +/- 0.016) and in non-MI regions (0.964 +/- 0.018), indicating temporally homogeneous radial shortening. A significant temporal heterogeneity in wall motion was demonstrated in MI regions (0.480 +/- 0.304) (p less than 0.001). In comparison with normal b values (0.449 +/- 0.106), there were decreased b values in MI regions (0.203 +/- 0.211) (p less than 0.001) and increased b values in non-MI regions (0.695 +/- 0.213) (p less than 0.001), suggesting hypokinetic and compensative hyperkinetic contraction in corresponding regions. Thus, temporal and spatial wall motion throughout systole could be assessed quantitatively by the present computer-assisted method with two simple integrated parameters.

Adult↗
PubMed1984

Induction of hyperpyrexia by dihydrocurvularin, a metabolic product of Penicillium gilmanii.

The previously reported rise in rectal temperature that follows the intravenous injection of the mixture of metabolic products (extractable with ether from the Czapek Dox medium on which Penicillium gilmanii has grown) is due to a single compound, dihydrocurvularin. Intravenous injection of 1-10 micrograms of dihydrocurvularin into rabbits causes a rise of at least one degree in rectal temperature of rabbits in 2-8 h. The degree of temperature rise depends more on the individual rabbit than on the quantity of dihydrocurvularin injected. Treatment with lipopolysaccharide abolishes the ability of dihydrocurvularin to cause a rise in rectal temperature. Treatment with dihydrocurvularin, however, does not abolish the ability of lipopolysaccharide to induce a temperature response or a leukocytosis. Rabbits respond to repeated treatment with dihydrocurvularin with a rise in rectal temperature that is indistinguishable from that observed on their first injection. Treatment with dihydrocurvularin does not affect differential counts or the concentration of leukocytes or red blood cells in the circulatory system.

Animals↗
PubMed1976

Effect of skin or muscle incisions or the loss of blood on serum leucogenenol level.

It has been found that damage to a tissue of a rabbit or a rat, such as results from a skin incision or an incision through the skin and muscles into the abdominal cavity, is followed 24 hr later by a significant increase in the concentration of leucogenenol in the animal's serum. Likewise, loss of approximately one-quarter to one-half of the blood in the circulation of rabbits or rats causes an increase 24 hr later in the animals' serum leucogenenol concentration.

Animals↗
PubMedDate not supplied

Sublytic complement injury does not activate NF-kappa B, or induce mitogenesis in rat mesangial cells.

Sublytic complement injury to glomerular mesangial cells, mediated by the terminal membrane attack complex of complement (C5b-9), is a potential initiating mechanism in IgA nephropathy. Sublytic complement injury has been reported to result in the production of a variety of pro-inflammatory molecules and growth factors, including many regulated by the transcription factor NF-kappa B. To determine the importance of complement injury in the pro-inflammatory signalling which occurs in IgA nephropathy, we investigated NF-kappa B activation following sublytic complement injury to cultured rat glomerular mesangial cells (RMCs). A sublytic dose of rabbit anti-Thy 1.1 (THY) serum and normal human serum was selected based upon flow cytometry, chromium-release assay, and induction of superoxide production. No significant C5b-9-induced NF-kappa B activation was detected by electrophoretic mobility shift assays, luciferase activity of RMCs transfected with a NF-kappa B-driven luciferase reporter construct, nor by Northern blots for the NF-kappa B-responsive mRNA species monocyte chemoattractant protein-1 or I kappa B alpha. Furthermore, measurements of (3)H incorporation following sublytic complement injury showed inhibition of mesangial cell mitogenesis in comparison to the heat-inactivated serum treatment and to THY alone. The results of this study suggest that sublytic complement injury to RMC does not directly activate NF-kappa B nor induce mesangial cell proliferation in mesangial cells. Other mechanisms such as IgA immune complex formation must be required to produce these events in IgA nephropathy.

Animals↗
PubMedDate not supplied

Non-lethal Candida albicans cph1/cph1 efg1/efg1 transcription factor mutant establishing restricted zone of infection in a mouse model of systemic infection.

The cph1/cph1 efg1/efg1 Candida albicans mutant cells were non-lethal in a mouse model of systemic infection. We investigated in vivo proliferation and invasion of C. albicans cells in infected mice to elucidate the interaction between the host and the pathogen. Homogenates of kidneys from the mice infected with the wild-type and the mutant C. albicans cells yielded a mean of 2.1 x 10 7 CFU/g and 2.2 x 10 6 CFU/g, respectively. The kidneys from the mice infected with the wild-type cells showed extensive renal cortical necrosis associated with neutrophilic infiltration. There were also wild-type hyphal cells present in abundance. Hence, tubular necrosis leading to renal failure in the mice may be the cause of death. Although the cph1/cph1 efg1/efg1 mutant cells were not lethal, they were capable of establishing restricted zones of infection and colonization near the renal pelvis instead of simply being cleared by the immune system in mice.

Animals↗