Biomedical subjects

C C Wu

Publications and source records attributed to C C Wu.

At least 217 records · Page 12Linked to original sources

PubMed1997

YC-1, a nitric oxide-independent activator of soluble guanylate cyclase, inhibits platelet-rich thrombosis in mice.

YC-1 (3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole), a nitric oxide (NO)-independent activator of soluble guanylate cyclase, has been shown to inhibit platelet activation and aggregation in vitro through the generation of cGMP. In the present study, we assessed the antithrombotic effect of YC-1 in models of experimental thrombosis in mice. YC-1 (10, 30 micrograms/g, i.p.)-treated mice showed a prolonged tail bleeding time 30 min after injection (from control 91.0 +/- 6.4 s to 208.6 +/- 22.7 s and 291.8 +/- 42.4 s, respectively). In contrast, aspirin at a dose of 30 micrograms/g (i.p.) prolonged the bleeding time to more than 600 s. Platelet-rich thrombus formation was induced by irradiation of the mesenteric venule with filtered light in mice pretreated intravenously with fluorescein sodium. YC-1 (30 micrograms/g, i.p.) markedly prolonged the occlusion time of irradiated venules (from control 146.1 +/- 19.0 s to 275.6 +/- 24.5 s) in heparinized (1 U/g) mice. In the same condition, aspirin (100 micrograms/g) only slightly prolonged the time required for occlusion (193.2 +/- 13.2 s). In a model of fatal pulmonary thromboembolism induced by intravenous injection of ADP (300 micrograms/g), YC-1 was effective in reducing mortality when administered intraperitoneally at doses of 10-30 micrograms/g. The antithrombotic effect of YC-1 was correlated with the inhibition of ADP-induced platelet aggregation ex vivo. In contrast, aspirin (30, 100 micrograms/g) did not inhibit ADP-induced pulmonary thromboembolism in vivo or platelet aggregation ex vivo. YC-1 (3, 10 micrograms/g) also exhibited profibrinolytic activity ex vivo, as revealed by shortening of the euglobulin clot lysis time. Therefore, YC-1 is an effective antithrombotic agent in preventing thrombosis in animal models, and its antiaggregating and additional profibrinolytic effects may be of potential clinical benefit in the treatment of thromboembolic diseases.

Adenosine Diphosphate↗

PubMed1997

Ketamine inhibits nitric oxide synthase in lipopolysaccharide-treated rat alveolar macrophages.

PURPOSE: To evaluate the effects of ketamine on the activity and protein expression of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide (LPS) in rat alveolar macrophages. METHODS: Pulmonary alveolar macrophages isolated from Wistar-Kyoto rats were used. After incubation of macrophages with ketamine (1, 10, or 100 microM) and LPS (1 microgram.ml-1) for 24 hr, the cell-free medium was removed for measuring the nitrite and tumour necrosis factor-alpha (TNF-alpha) levels by Griess reaction and ELISA kit, respectively. The harvested macrophages were also used to determine the activity of iNOS by using the conversion of [3H]-L-arginine to [3H]-L-citrulline method. In addition, the protein expression of iNOS was detected by Western blot analysis. RESULTS: In rat alveolar macrophages, (i) ketamine (1 to 100 microM) caused a dose-dependent suppression of the production of nitrite and TNF-alpha induced by LPS and (ii) ketamine (100 microM) inhibited the activity (46.5 +/- 4.8%, P < 0.05) and protein expression (35 +/- 11%, P < 0.05) of iNOS in response to LPS. CONCLUSION: These results show that ketamine inhibits the activity and expression of iNOS in LPS-activated alveolar macrophages, which may be associated with the reduction of the release of TNF-alpha following LPS treatment.

Analysis of Variance↗

PubMed1997

Clinical experience in radical lymphadenectomy for adenocarcinoma of the gastric cardia.

OBJECTIVES: We evaluated the pattern of nodal metastasis and its prognosis after radical lymphadenectomy in adenocarcinoma of the gastric cardia. METHODS: We conducted a retrospective cohort study of 70 patients (52 men and 18 women; mean age 63.6 years) with adenocarcinomas of the gastric cardia who underwent extended gastrectomy (65 total gastrectomies and 5 proximal gastrectomies) and radical lymphadenectomy (D2 to D4) at Taichung Veterans General Hospital between 1989 and 1995. RESULTS: Twenty-four complications developed in 22 (31.4%) patients, and seven (10.0%) hospital deaths occurred. An overall 5-year cumulative survival of 37.6% was obtained. Lymph node metastases were identified in 53 (75.7%) patients. Nodal involvement was closely related to the depth of tumor invasion (p = 0.005). When the gastric wall invasion was limited to the subserosal layer (T1 and T2, n = 15), no patient had N4 group nodal metastasis. Once the serosal layer had been involved (beyond T3), N4 group nodal metastasis was frequently seen (30.9%, 17 of 55 patients). A multivariable analysis revealed that the level of nodal involvement, the depth of tumor invasion, and the presence of complications were independent prognostic factors. Cumulative 5-year survivals of curability A (n = 12), B (n = 19), and C (n = 32) resections were 100%, 21.2%, and 27.5%, respectively (p = 0.0001). The long-term survival of the patients after resection was also closely related to their pTNM stages (p = 0.0004). CONCLUSIONS: We conclude that gastrectomy accompanied by radical lymphadenectomy provides a reasonable long-term survival expectancy that is closely related to the stage of the disease and the curability of resection.

Adenocarcinoma↗

PubMed1997

Role of nitric oxide in lipopolysaccharide-induced mortality from spontaneously hypertensive rats.

To investigate whether nitric oxide (NO) contributed to a higher mortality induced by lipopolysaccharide (LPS) in spontaneously hypertensive rats (SHR), NO synthase inhibitors were used to examine the mortality from LPS in SHR and normotensive Wistar-Kyoto (WKY) rats. We evaluated the mortality from LPS in a series of doses (5, 10, or 20 mg/kg, i.v.) in the anesthetized rat. Plasma nitrite was measured before and at 1, 2, and 3 h after treated rats with LPS (5 mg/kg, i.v.). Pressure responses to N omega-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine (AG) were performed in rats treated with or without LPS for 3 h. Thoracic aortic cyclic guanosine 3',5'-monophosphate (cGMP) levels were also assessed. Our results demonstrated that injection of LPS caused a dose-dependent mortality in both strains, having a more marked effect in SHR. The survival time of rats after injection of LPS (5 mg/kg, i.v.) was much shorter in SHR. A higher basal level of plasma nitrite was observed in SHR and this difference was further augmented by LPS. The administration of L-NAME (3 mg/kg, i.v.) and AG (15 mg/kg, i.v.) 3 h after LPS had no significant effects on the survival time of WKY rats, but significantly prolonged that of SHR to a similar time of WKY rats. The injecton of L-NAME prior to LPS increased blood pressure of WKY rats by 28+/-5 mmHg and increased that of SHR by 38+4 mmHg. At 3 h after LPS, L-NAME had a greater pressor effect in SHR than in WKY rats. By contrast, before rats injected with LPS, AG slightly increased blood pressure of SHR by 7+/-3 mmHg but not of WKY rats (3+/-2 mmHg), whereas it also had a greater pressor effect in SHR than in WKY rats after treated rats with LPS for 3 h. In addition, LPS induced a higher level of cGMP in SHR than in WKY rats, which was attenuated by in vitro treatment of aortic rings from LPS-rats with L-NAME or AG to a similar level in SHR and WKY rats. These results suggest that a higher level of NO evoked by LPS is associated with a higher mortality in SHR and we propose that the elevated NO synthesis in SHR may play an important role in the compensatory mechanisms activated to combat the hypertensive state.

Animals↗

PubMed1997

Comparison of aging and hypercholesterolemic effects on the sodium inward currents in cardiac myocytes.

To study and to compare the hypercholesterolemic and aging effect on the sodium inward currents (I(Na)) in cardiac myocytes, whole-cell clamp recordings were made in single cardiac myocyte isolated from normo- and diet-induced hypercholesterolemic rabbits of different age groups. The cell capacitance of adult and hyperlipidemic myocytes seemed larger than that of young and normolipidemic ones. However, the sodium current density at a holding potential of -80 mV on adult and hypercholesterolemic ventricular sarcolemma was significantly lower than that on young and normolipidemic one (adult hyperlipidemic: -15.3+/-2.4 pA/pF (n=16), adult control: -28.1+/-3.4 pA/pF (n=13), young hyperlipidemic: -39.5+/-5.4 pA/pF (n=19), young control: -67.3+/-7.8 pA/pF (n=12)). In aging process, this effect was due to a decrease in channel number, a leftward shift in the inactivation potential and a slowing of the time course of recovery. In hypercholesterolemia, however, the major cause was due to the functional change of sodium currents. In addition to decreasing the sodium current magnitude, hypercholesterolemia lowered the threshold for excitation of cardiac myocytes (-50 mV vs -40 mV). In conclusion, aging process depressed the sodium channel activity in ventricular myocytes. In addition to inducing some similar functional alterations of I(Na) as aging process, long-term hypercholesterolemia could also increase the excitability in cardiac myocytes, which was different from aging process.

Aging↗

PubMed1997

Quantitative competitive polymerase chain reaction for detection and quantification of infectious bursal disease virus cDNA and RNA.

A polymerase chain reaction (PCR)-based method to measure complementary DNA (cDNA) and RNA levels of infectious bursal disease virus (IBDV) was developed. Quantification was achieved by quantitative competitive PCR (QC-PCR) amplification. A competitor, a deletion mutant of the wild type IBDV cDNA, was 10-fold serially diluted and co-amplified with IBDV cDNA after being reversely transcribed from the viral RNA. After agarose gel electrophoresis, staining, and densitometric scanning, the bands on the digitized images were analyzed and quantified by computer-assisted image analysis. Complementary DNA of standard, as well as variant strains, of serotype 1 IBDV was detected and quantified using the same QC-PCR procedures. The assay could measure IBDV cDNA levels ranging from 1 microgram to 45 fg and RNA levels ranging from 9 micrograms to 45 fg. The results indicated that QC-PCR is sensitive, easy to perform, and suitable for routine quantitation of IBDV cDNA or RNA levels.

Animals↗

PubMed1997

Myocardial stunning after cerebral infarction.

Myocardial stunning has not been described in patients with cerebrovascular accidents. We present a patient in whom inferior wall hypokinesis, ST-segment elevations and Q waves developed after acute right hemisphere ischemic stroke. Total recovery ensued within 5 days. Coronary vasospasm induced by stroke-related sympathetic surge might be the cause of this cardiac event.

Aged↗

PubMed1997

Evaluation of a heterologous metallothionein gene promoter in transfected mosquito cells.

Mosquito cells from the C7-10 Aedes albopictus line were transfected with a recombinant plasmid containing the Escherichia coli galactokinase gene under control of the promoter from the Drosophila melanogaster metallothionein gene, Mtn. Consistent with what has been observed with heterologous metallothionein promoters in several vertebrate systems, treatment of transiently transfected mosquito cells with CuSO4 or CdCl2 induced a 2- to 5-fold increase in galactokinase gene expression. Levels of enzyme activity were not increased in tests using stably transformed lines despite wide ranges in the number of transfected gene copies detected in Southern blots. The importance of comparative studies with gene constructs that may eventually be used to produce genetically modified mosquitoes is underscored by the apparent variability in activity of heterologous promoters from D. melanogaster in different mosquito cell lines.

Aedes↗

PubMed1997

Experimental infection of young specific pathogen-free cats with Bartonella henselae.

Eighteen 12-week-old specific pathogen-free cats, blood culture- and serum antibody-negative for Bartonella henselae, were randomly allocated to groups and were intravenously inoculated with 10(10) (group 1), 10(8) (group 2), or 10(6) (group 3) B. henselae or with saline (group 4) or were not inoculated (group 5). Cats were humanely killed at 2, 4, 8, 16, and 32 weeks after inoculation. All B. henselae-inoculated cats were bacteremic by 2 weeks after infection. Bacteremia persisted until 32 weeks after infection in 1 cat. Cats in groups 1 and 2 had fever (>39.7 degrees C) and partial anorexia by 2 weeks after infection that lasted 2-7 days. All infected cats had Bartonella-specific IgM and IgG serum antibodies and lymphocyte blastogenic responses. Histopathologic lesions were observed in multiple organs of infected cats through 8 weeks after infection. Cats were readily infected with B. henselae by intravenous inoculation, developed histopathologic lesions that apparently resolved, and developed B and T lymphocyte responses to infection.

Animals↗

PubMed1997

Photochemical production of uracil quantified in bromodeoxyuridine-substituted SV40 DNA by uracil DNA glycosylase and a lysyl-tyrosyl-lysine tripeptide.

Exposure to UVA radiation of SV40 DNA substituted with bromodeoxyuridine (BrdU) in the presence of Hoechst dye 33258 results in the production of uracil. The yield of uracil was determined by measuring the increase in the single-strand break (SSB) yield after incubation of the photolyzed DNA with uracil-DNA glycosylase (UDG) in the presence of the tripeptide lysyl-tyrosyl-lysine (KYK). UDG removes uracil to leave an abasic site which is then cleaved to a SSB by KYK. The SSB yield was quantified by digital video imaging of ethidium fluorescence after separation of the I, II and III forms of SV40 DNA by agarose gel electrophoresis. Uracil is not detected when photolysis is carried out in the absence of the dye nor when unsubstituted DNA is used as the substrate. Without UDG or KYK treatment, the F0 for the loss of form I DNA is 100 J/m2. This falls to 13 J/m2 after incubation with UDG and KYK, indicating that uracil formation is approximately 5-fold more efficient than SSB formation. Formation of uracil suggests a mechanism for the high cellular toxicity of the dye-BrdU-UVA treatment.

Bromodeoxyuridine↗

PubMed1997

Primary coexistent adenocarcinoma and choriocarcinoma of the stomach. A case report and review of the literature.

We report a case of primary gastric choriocarcinoma with liver metastasis. The mixed histologic patterns included adenocarcinoma, undifferentiated carcinoma, and choriocarcinoma. Immunohistologic staining for the beta-subunit of human chorionic gonadotrophin (beta-HCG) showed positive results in the choriocarcinoma, adenocarcinoma, and normal mucosal gland. However, positive HCG cells were present at different intensities in the choriocarcinoma, adenocarcinoma, and normal mucosal gland. The level of HCG was significantly increased in serum. This unusual tumor probably resulted from dedifferentiation of a primary adenocarcinoma or developed directly from the mucosal glands.

Adenocarcinoma↗

PubMed1997

Loss of acetylcholine-induced relaxation by M3-receptor activation in mesenteric arteries of spontaneously hypertensive rats.

This study investigated which subtype of muscarinic receptor in mesenteric arteries from SHRs mediates the loss of the release of nitric oxide (NO) or endothelium-derived hyperpolarizing factor (EDHF) in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats. After SHRs and WKY rats were killed, their superior mesenteric arteries were isolated to perform the vascular relaxation study. Acetylcholine (ACh, 1 nM-1 microM)-induced relaxation was in a concentration-dependent manner and was impaired in mesenteric arterial rings obtained from the SHR group, whereas nitroglycerin (10 nM-1 microM)-induced relaxation was not affected in endothelium-denuded rings obtained from the hypertensive rat. In the presence of N(omega)-nitro-L-arginine (L-NNA; 0.1 mM) or methylene blue (10 microM), the ACh-induced relaxation was partially attenuated in both SHRs and WKY rats. The relaxation of ACh was partially inhibited by 4-aminopyridine (4-AP; 1 mM), apamin (APM; 1 microM), or charybdotoxin (CTX; 0.1 microM) in WKY rats, whereas that relaxation was not affected by 4-AP, APM, or CTX in SHRs. However, the L-NNA-resistant relaxation of ACh was further inhibited by APM or CTX in WKY rats but not in SHRs. When arterial rings were precontracted by 60 mM K+, the ACh-induced relaxation was not significantly different in SHRs and WKY rats. However, this relaxation was abolished by L-NNA (0.1 mM) in both strains. In addition, the M3 muscarinic antagonist, 4-diphenylacetoxy-N-methylpiperidine was the most potent in inhibiting the relaxation of ACh, being more potent than pirenzepine and methoctramine, which preferentially block M1 and M2 receptors in the mesenteric artery of WKY rats, respectively. 2-Nitro-4-carboxyphenyl-N,N-diphenylcarbamate (1 microM) almost abolished the relaxation of ACh, but not of A23187, in SHRs and WKY rats. These results suggest that NO and EDHF are released from the endothelium of rat mesenteric artery on the activation of muscarinic M3-receptor by ACh, and the loss of ACh-induced relaxation in small arteries of SHRs is mainly through reducing the release or activity or both of EDHF.

Acetylcholine↗

PubMed1997

Treatment of femoral shaft aseptic nonunions: comparison between closed and open bone-grafting techniques.

OBJECTIVE: The aim of this prospective study was to investigate and compare the effects of closed and open bone-grafting techniques in the treatment of femoral shaft aseptic nonunions. MATERIALS AND METHODS: Forty consecutive femoral shaft aseptic nonunions with inserted reamed intramedullary nails were randomly divided into two groups. The indications for these techniques were aseptic nonunions with less than 1 cm of shortening, no rotational or angular misalignment, and no large bony defects. The closed technique consisted of intramedullary reaming to a larger size and reinsertion of a stable intramedullary nail. The open technique consisted of local debridement, maintaining local stability with or without supplementation, and upper tibial cancellous bone grafting. RESULTS: Thirty-five cases were followed up for at least 1 year (range, 1-3 years), and all achieved solid unions. There were no significant complications. The union period with the closed technique was significantly shorter than with the open technique (4.0 +/- 0.6 months vs. 5.1 +/- 0.8 months; p < 0.01, Student's t test). The operating time with the closed technique was also significantly shorter than with the open technique (36 +/- 7 minutes vs. 58 +/- 14 minutes; p < 0.01, Student's t test). There was no significant difference in other parameters between the two techniques. CONCLUSIONS: The closed bone-grafting technique had clinical results similar to those of the open technique. The surgical procedure was simpler, however, and the union period was shorter. Whenever possible, therefore, the closed technique should be considered in all indicated cases.

Adolescent↗

PubMed1997

The effect of dynamization on slowing the healing of femur shaft fractures after interlocking nailing.

OBJECTIVE: The aim of this retrospective study was to investigate the effect of dynamizing a static interlocking nail to promote femoral fracture healing and the adverse effect of dynamization. MATERIALS AND METHODS: Twenty-eight static femoral interlocking nails were dynamized after 4 months (median, 6 months; range, 4-12 months) because of poor fracture healing. The clinical and roentgenographic healing processes were recorded. Significant complications were treated and analyzed. RESULTS: Twenty-four patients were followed for at least one year (median, 32 months; range, 13-49 months). Fourteen patients (58%) achieved a solid union with a union period of 5.2 +/- 2.0 months after dynamization. Twenty-one percent of patients (5 of 24) had more than 2 cm of femoral shortening; all occurred in cases of nonunion (p < 0.01, Fisher's exact test). All 10 cases of nonunion were treated with cancellous bone grafting with or without lengthening and achieved satisfactory outcomes. CONCLUSIONS: Dynamization is a method that can be tried to improve fracture healing in femoral fractures that show delayed healing after interlocking nailing. In my experience, however, not all cases achieve union after dynamization. Patients must be examined regularly after dynamization to avoid significant shortening.

Adult↗

PubMed1997

The value of 67Ga-citrate scanning in psoas abscess.

Psoas abscess is a serious health problem which presents with non-specific symptoms and signs. To reduce morbidity and mortality, it is important to diagnose the presence and extent of a psoas abscess accurately using imaging studies. Because the 67Ga scan may facilitate the early diagnosis of insidious infection and assist CT-guided percutaneous drainage of the abscess, we examined the value of 67Ga scans in 18 patients with psoas abscess. The imaging results of 67Ga scans (18 patients), computed tomography (CT) (16 patients) and bone scans (13 patients) were analyzed. In this series, concomitant infections were very common (94%) in patients with psoas abscess. For detecting psoas abscess, the sensitivity of 67Ga scanning (92%) and CT (91%) was similar. However, 67Ga scanning is superior to CT in demonstrating concomitant infectious foci at other sites. Bone scanning is a sensitive tool for depicting osteomyelitis, which was common in this series of patients. We also found that increased vascularity in the psoas area was demonstrated by three-phase bone scanning in 60% of patients.

Adult↗

PubMed1997

Accuracy of the conductance catheter for measurement of ventricular volumes seen clinically: effects of electric field homogeneity and parallel conductance.

The conductance-volume method is an important clinical tool which allows the assessment of left ventricular function in vivo. However, the accuracy of this method is limited by the homogeneity of electric field the conductance catheter produces and the parallel conductance of surrounding structures. This paper examines these sources of error in volumes seen clinically. The characteristics of electric field within a chamber were examined using computer simulation. Nonconductive and conductive models were constructed and experimental measurements obtained using both single-field (SF) and dual-field (DF) excitation. Results from computer simulations and in vitro measurements were compared to validate the purposed theoretical model of conductance-volume method. The effects of field homogeneity and significance of parallel conductance in volume measurement were then determined. The results of this study show that DF provide a more accurate measure of intraventricular volume than SF, especially at larger volumes. However, both significantly underestimate true volume at larger volumes. In addition, the parallel conductance due to the chamber wall is significant at small volumes, but diminishes at larger volumes. Furthermore, the effect of parallel conductance beyond the chamber wall may be negligible. This study demonstrates the limitations in applying current conductance technology to patients with dilated hearts.

Animals↗

PubMed1997

Healing of 56 segmental femoral shaft fractures after locked nailing. Poor results of dynamization.

We treated 56 consecutive acute segmental femoral shaft fractures with closed static locked nailing. 12 nails were dynamized after 6 (5-10) months due to slow fracture healing and 5 united after another 5 (3-8) months. The other 7 required cancellous bone grafting and all healed uneventfully 6 (5-8) months after grafting. Since dynamization did not promote healing in most of our cases we suggest early cancellous bone grafting in cases of delayed union.

Adult↗

PubMed1997

Salmonella arizonae sepsis in a lynx.

A 4.5-wk-old lynx (Felis lynx) was presented for necropsy with a history of poor growth, mild diarrhea, anemia, and lethargy. The liver was enlarged and had a 7 mm long fracture that resulted in severe intraabdominal hemorrhage and death. Microscopic lesions were indicative of severe ulcerative cystitis and septicemia. Pure cultures of Salmonella arizonae were isolated from the liver, kidney, and spleen. Based on differences in the chronicity of inflammation in the urinary bladder versus other organs, we speculate that chronic cystitis caused by S arizonae lead to septicemic infection.

Animals↗