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Biomedical subjects

S C Chen

Publications and source records attributed to S C Chen.

At least 19 recordsLinked to original sources
PubMed1992

A comparison of hospital and community-acquired infective endocarditis.

The epidemiology, clinical features, microbiology and outcome of 30 episodes of nosocomial endocarditis occurring over a 13-year period were reviewed and compared with 148 cases of community-acquired endocarditis. Twenty-eight patients (93%) had been in hospital for > 1 week and 10 patients (33%) for > 1 month when they developed endocarditis. Left-sided infection was most frequent; only 3 cases involved the tricuspid valve. Compared with community-acquired infection, patients tended to be older, had a greater incidence of congestive cardiac failure (p = 0.001) or hypotension (p = 0.0008) at presentation and were more likely to have bacteremia after an invasive procedure (83 vs 31%; p < 0.00001). Intravascular devices were the presumed source of bacteremia in 11 cases (37%); the same organism was isolated from both the blood and the suspected source of infection. Staphylococcus aureus was the most frequent causative organism, accounting for 17 episodes (57%), including 4 (13%) due to methicillin-resistant strains. Nosocomial endocarditis had a significantly higher mortality than did community-acquired infection (40 vs 18%; p = 0.02). Eight patients (27%) needed valve replacement. Proper adherence to protocols for management of intravascular devices and appropriate antimicrobial prophylaxis before procedures may have prevented endocarditis in 15 of 30 patients.

Adult↗
PubMed1992

The role of hepatitis B and C viruses in hepatocellular carcinoma in a hepatitis B endemic area. A case-control study.

To investigate the role of hepatitis B (HBV) and C viruses (HCV) in hepatocellular carcinoma (HCC) in an HBV endemic area and elucidate the interaction of these two viruses, a case-control study of 128 patients with HCC and 384 age-matched and sex-matched control subjects was done. The positive rates of hepatitis B surface antigen (HBsAg, 77.3%, 99 of 128) and anti-HCV (19.5%, 25 of 128) in patients with HCC were significantly higher than in control subjects (P less than 0.001). Both HBsAg and anti-HCV were important risk factors for HCC (relative risks, 13.96 and 27.12, respectively), and the risk for HCC was elevated significantly to 40.05 (95% confidence interval, 12.57 to 127.6) when HBsAg and anti-HCV were considered simultaneously. These results suggested that HBV and HCV were associated highly with HCC in an HBV endemic area and that these two viruses might contribute independent but synergistic effects to the pathogenesis of HCC.

Adult↗
PubMed1992

Treatment of hepatocellular carcinoma by transcatheter arterial chemoembolization and analysis of prognostic factors.

A total of 100 patients with histologically proven hepatocellular carcinoma (HCC) underwent transcatheter arterial chemoembolization (TACE) and were followed for more than 1 year and 10 months. Portal vein branch thrombosis was diagnosed in 14 patients, and extrahepatic metastasis was noted in 11 subjects. The embolization material used was iodized oil (0.1-0.2 ml/cm tumor area at its maximal diameter), which was prepared by pumping with contrast agent and then mixed with anticancer drugs; Gelfoam particles measuring 1-2 mm in size were subsequently injected. The overall cumulative 0.5- 1-, 2-, and 3-year survival rates were 81%, 57%, 31%, and 21%, respectively. Patients with an intact capsule and those with solitary lesions, especially when the tumor diameter was < 5 cm, achieved a higher survival rate. In contrast, incomplete TACE, extrahepatic metastasis, and portal vein thrombosis were associated with the worst outcome. Patients with positive HBsAG and diffuse or multiple tumors also showed a poor outcome. Early diagnosis and early treatment of HCC are the keys for the achievement of better clinical results.

Adult↗
PubMed1992

Radiotherapy in the treatment of hepatocellular carcinoma and its metastases.

A study was conducted to evaluate the effect of external radiation therapy on hepatocellular carcinoma (HCC) and its metastatic lesions. A total of 33 patients with cytopathologically proven HCC were subjected to radiation therapy over a 4-year period, and treatment was discontinued in 8 cases due to jaundice, severe discomfort, or early mortality. Thus, 25 patients with 28 lesions underwent irradiation with a total dose ranging between 3000 and 5600. Of these, seven were irradiated for liver tumors, and the results showed that two lesions decreased in size, the symptoms improved in 1 case, and another patient maintained stable disease for 4 months. Among the 21 metastatic lesions treated, only 2 patients failed respond to the treatment. Nine subjects were irradiated for bone metastases, and the bone pain subsided in all but one case. The survival for bone metastasis was as long as 23 months when the primary tumor was treated effectively. Three of the four cases of irradiated skin nodules disappeared and had not recurred after 5 months, 1 year, and 4 years, respectively. Tumor shrinkage or symptoms of relief were noted for three abdominal lymph nodes, one neck lymph node, one pleural tumor, and one lung tumor. Clinical improvement associated with a stable lesion was observed in two patients with brain metastasis. Follow-up revealed regrowth of the tumor or recurrence of symptoms in most of the patients. However, none of the patients died as a direct result of a metastatic lesion. Although external radiation therapy is palliative in intent, it appears to be useful in the treatment of HCC and its metastatic lesions.

Adult↗
PubMed1992

Antimicrobial susceptibility of anaerobic bacteria in Australia.

The susceptibilities of 900 clinical isolates of anaerobic bacteria to 14 antimicrobial agents were determined by an agar dilution technique. Chloramphenicol, imipenem and metronidazole were found to be active against virtually all of the strains; only a single Bacteroides fragilis isolate was resistant to both imipenem and metronidazole. The addition of clavulanic acid to amoxycillin and ticarcillin potentiated the activities of these agents against all anaerobes including members of the B. fragilis group. Ampicillin/sulbactam and clindamycin were the next most active agents, 91 and 89% of isolates respectively being susceptible. Seventy-three per cent of the bacteria tested were susceptible to cefoxitin and 65% to cefotetan, with the MICs of almost 50% of the isolates clustering between 16 and 32 mg/L. There was also clustering around the breakpoint (64 mg/L) of piperacillin. Azithromycin exhibited poor activity against the B. fragilis group; only 18% of isolates were susceptible to < or = 4 mg/L. However, 92% of non-B. fragilis Bacteroides group strains were susceptible to this agent. We conclude that imipenem, metronidazole, chloramphenicol, ticarcillin/clavulanate, co-amoxiclav and, to a lesser extent, ampicillin/sulbactam are suitable as empirical therapy for infections caused by anaerobic bacteria.

Anti-Bacterial Agents↗
PubMed1992

Lineage switch macrophages can present antigen.

Recent reports of "lineage switching" from a lymphoid to macrophage phenotype have left unresolved the question of whether such cells are functional macrophages or nonfunctional products of differentiation gone awry. This study demonstrates that several "macrophage-like" cell lines derived from v-Ha-ras-transformed pre-B cells have gained the capacity to effectively present antigen in MHC-restricted fashion. Using an assay involving the cocultivation of putative antigen-presenting cells with chicken ovalbumin (cOVA) and a cOVA-specific T-cell hybridoma, "lineage switch" cell lines were found to present antigen as effectively as macrophage-containing peritoneal exudates. Neither the original pre-B-cell precursors nor B-cell lymphomas derived from them present antigen. Thus, we have demonstrated that these "lineage switch" macrophages are capable of antigen presentation, a mature differentiated function. While gaining macrophage characteristics, these cells have also rearranged their kappa light-chain immunoglobulin locus, suggesting that macrophage differentiation and immunoglobulin rearrangement are not mutually exclusive processes. The existence of both lymphoid and myeloid characteristics in a cell fully capable of antigen presentation suggests greater plasticity in hematopoietic lineage commitment than conventionally thought to be the case.

Animals↗
PubMed1992

Duplex pulsed Doppler sonography in the differential diagnosis of hepatocellular carcinoma and other common hepatic tumours.

180 previously untreated consecutive patients with liver tumours (308 lesions), including 104 hepatocellular carcinomas (148 lesions), 43 metastases (116 lesions) and 33 haemangiomas (44 lesions), were studied to determine the value of duplex sonography in the differentiation of hepatocellular carcinoma from other tumours. For lesions measuring less than or equal to 5 cm in diameter, hepatocellular carcinoma demonstrated the highest rate and haemangioma demonstrated the lowest rate of Doppler signals from within the lesions. To differentiate malignancy from haemangioma, the presence or absence of Doppler signals from these lesions were used as criteria. The specificity and positive predictive value were very high (100%, 100%), but the sensitivity, negative predictive value and accuracy were low (61.5%, 48.3%, 71.7%, respectively). With one exception, all lesions measuring less than 3 cm in diameter with detectable Doppler signals were hepatocellular carcinoma. Using these results it is possible to differentiate hepatocellular carcinoma from metastases and haemangioma with high sensitivity, specificity, positive and negative predictive value, and accuracy (80.8%, 96.4%, 95.5%, 84.4%, 88.9%, respectively, for metastases; 80.8%, 100%. 100%, 81.5%, 89.6%, respectively, for haemangioma). We conclude that Doppler signals from within a lesion in combination with its size can aid differentiation of hepatocellular carcinoma from two other kinds of common hepatic tumour.

Adult↗
PubMed1992

Concurrent zidovudine-induced myopathy and hepatoxicity in patients treated for human immunodeficiency virus (HIV) infection.

Myopathy and hepatic toxicity are important complications of zidovudine (3'-azido-3'-deoxythymidine therapy) in patients infected with the human immunodeficiency virus (HIV) both may also occur in HIV infection in the absence of zidovudine therapy. We report 2 cases of myopathy caused by zidovudine, occurring within 16 wks of initiation of therapy, and a case of concurrent hepatic and muscle toxicity. In one case, electron microscopy demonstrated characteristic enlarged mitochondria with paracrystalline inclusions. This technique can distinguish the myopathies caused by either HIV or zidovudine. Both zidovudine-induced myopathy and hepatoxicity require discontinuation of the drug if severe.

Adult↗
PubMed1992

Clinical utility of pulsed Doppler in the detection of arterioportal shunting in patients with hepatocellular carcinoma.

Ninety-seven patients with hepatocellular carcinoma had duplex scanning from the patent or residual portal lumen and comparative angiography. Duplex ultrasonography identified five of nine patients with angiographic evidence of arterioportal shunting. Furthermore, Doppler results indicated the presence of the shunt in one patient without angiographic evidence. Duplex scanning from the portal lumen may be useful in the detection of arterioportal shunting. This procedure can be used to evaluate the hemodynamic change of the recipient portal vein under natural physiologic conditions. However, small shunts without hepatofugal portal blood cannot be detected by this procedure.

Adult↗
PubMed1992

Inhibitory effect of rhynchophylline on platelet aggregation and thrombosis.

Rhynchophylline (Rhy) inhibited rabbit platelet aggregation induced by arachidonic acid (AA), collagen, and ADP. The values of IC50 were 0.72, 0.74, and 0.67 mmol.L-1, respectively. Rhy reduced the thromboxane B2 (TXB2) generation in PRP induced by collagen but failed to reduce that induced by AA. Rhy suppressed malondialdehyde (MDA) formation in platelet suspension stimulated by thrombin, inhibited the platelet factor 4 (PF4) release. It did not alter intraplatelet cAMP concentration. Rhy 10-20 mg.kg-1 iv showed a significant inhibition of venous thrombosis and cerebral thrombosis in rats.

Alkaloids↗
PubMed1992

[Plasma renin activity, angiotensin II, angiotensin converting enzyme, thromboxane A2 and prostacyclin I2 levels in pigs with severe hypoxia and hypercapnea and acidosis shock].

To evaluate the role of certain plasma biosubstances on the development of pulmonary hypertension and shock during severe hypoxia, hypercapnia and acidosis, plasma renin activity (PRA), angiotensin II (ATII), angiotensin converting enzyme (ACE), TXB2 and 6-Keto-PGF1 alpha (the stable metabolites of TXA2 and PGI2) were assayed in blood from pulmonary artery and aorta in seven pigs. Pulmonary arterial pressure (PAP) was monitored via Swan-Ganz catheter. During hypoxic and hypercapnic ventilation, PaO2 dropped to 4.7 kPa, PaCO2 rose to 21.1 kPa, pH dropped to 6.82, PAP increased from 2.43 +/- 0.06 to 4.46 +/- 0.45 kPa when acidotic shock developed (all P less than 0.05). Meanwhile ATII levels rose (all P less than 0.05). PRA significantly increased during acidotic shock as compared with normal ventilation (P less than 0.02). ACE dropped significantly (P less than 0.05), TXB2 and 6-keto-PGF1 alpha showed no significant change before and after hypoxic and hypercapnic ventilation.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Angiodysplasia as a source of intestinal bleeding: report of seven cases.

From October 1978 to April 1991, seven patients presenting at the National Taiwan University Hospital with gastrointestinal tract hemorrhage were diagnosed by colonofibroscopy or angiography as having angiodysplasia of the colon and small intestine. There were two men and five women; their ages ranged from 23 to 65 years, with a mean age of 50.3 years. None of these patients were diagnosed by barium enema. Only two patients were diagnosed by colonofibroscopy, and six patients were diagnosed by angiography. Therefore, angiography was the most effective method for diagnosing angiodysplasia. A vascular tuft was the most frequent finding. Six patients with lesions on the right side of the colon underwent a right hemicolectomy, one patient with a lesion on the jejunum underwent a right hemicolectomy initially with segmental resection of the jejunum later. The postoperative courses were smooth, and there has been no further evidence of gastrointestinal blood loss or anemia in the follow-up period. A right hemicolectomy is the treatment of choice because these lesions are frequently multiple; the lesions are found primarily on the right side of the colon.

Adult↗
PubMed1992

Absence of genomes of DNA tumor viruses and expression of oncogenes and growth factors in two esophageal carcinoma cell lines of Chinese origin.

To study the oncogenesis of human esophageal carcinoma, the presence of DNA sequences homologous to several DNA tumor viruses and the expression of oncogenes and growth factor genes were examined in two esophageal carcinoma cell lines of Chinese origin, CE48T/VGH and CE81T/VGH. Southern blot analyses failed to detect sequences homologous to hepatitis B virus (HBV), Epstein-Barr virus (EBV), herpes simplex virus type 2 (HSV-2), cytomegalovirus (CMV) or human papilloma virus (HPV) genomes. Northern blot analyses revealed that c-myc, c-src, c-H-ras, c-abl, c-sis, and p53 genes were expressed. In addition, transcripts of transforming growth factor alpha (TGF alpha), TGF beta, and platelet derived growth factor A (PDGF A) genes were detected. These studies suggest that DNA tumor viruses may not be involved in the carcinogenesis of esophageal carcinoma. However, cooperation among different oncogenes and the production of growth factors may play an important role in that carcinogenesis.

Carcinoma↗
PubMed1992

[Effects of silybin on acute myocardial infarction and reperfusion injury in anesthetized rats].

The effects of silybin (Sil) on myocardial infarction size and ischemia- and reperfusion-induced arrhythmias were studied in anesthetized open chest Sprague-Dawley rats. It was found that pretreatment with Sil 20, 50, and 80 mg.kg-1 iv reduced significantly infarct size by 34.7%, 35.0%, and 50.6% respectively at 4 h after ligation. Sil prevented ischemic arrhythmia only at the dose of 80 mg.kg-1. In reperfusion experiment, pretreatment with Sil 20 mg.kg-1 decreased significantly reperfusion-induced arrhythmia.

Animals↗
PubMed1992

Interleukin-2 (IL-2) and IL-2-activated bone marrow in transplantation: evaluation from a clinical perspective.

Incubation of bone marrow (BM) with interleukin-2 (IL-2) in vitro results in generation of killer cells providing a tool for enhancing the graft-versus-tumor effect in transplantation. We have evaluated the influence of IL-2 on the progenitor cell activity (PCA), homing pattern of BM and hemopoiesis in a syngeneic bone marrow transplantation (BMT) model in mice. The PCA index and homing pattern of BM activated with IL-2 in vitro for 24 h (ABM) were similar to those of fresh bone marrow (FBM). In vitro culture of BM for more than 1 day resulted in progressive decline in its PCA index; this was not related to the presence or absence of IL-2 in the culture medium. Toxicity of IL-2 was related to the dose and not the time of institution of IL-2 therapy after BMT. Maximum tolerated dose of IL-2 instituted immediately after BMT was 10 times higher than the dose in a non-BMT setting. The pattern of marrow reconstitution following BMT with ABM was comparable to that with FBM. This study shows that BMT with BM activated with IL-2 for 24 h results in normal hemopoiesis, and IL-2 therapy instituted immediately after BMT with ABM does not cause additional toxicity.

Animals↗