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Biomedical subjects

C H Chen

Publications and source records attributed to C H Chen.

At least 199 records · Page 11Linked to original sources
PubMed2000

Core decompression for osteonecrosis of the femoral head at pre-collapse stage.

Twenty-five patients (27 hips) were retrospectively studied for core decompression in the treatment of osteonecrosis of the femoral heads at pre-collapse stage, Ficat and Alert stages I and II, from Apr. 1984 to Jun. 1998 with follow-up period at least 1 yr (mean 28 months). Eleven hips (10 patients) were considered to have failed due to progressive collapsed more than 2 mm, severe pain or reoperation. We further analyzed the results with regard to the stages, the size of the necrotic area according to the Ohzono classification, the lateral head index (LHI) and the Kerboul combined necrotic angle. The survival rate according to the Ohzono classification was type 1B: 100%, 1C: 44%, 2: 25%, and 3B: 0%. Hips with Kerboul angle less than 250 degrees revealed satisfactory results in all except one hip. All hips with Kerboul angle more than 250 degrees collapsed. Fourteen of the 15 hips (93%) with lateral head index more than 20% did not collapse and all hips except one (7/8) with LHI less than 12% collapsed. We conclude core decompression yields satisfactory results in osteonecrotic femoral heads at pre-collapse stage and with small necrotic area or good lateral buttress.

Adult↗
PubMed2000

A controlled study of postpartum depression in adult women.

The main purpose of the study was to examine the hypothesis that the postpartum period represents a time of increased risk for depression. The other psychosocial variables on stress, social support and self-esteem were also measured. Adult women, ranging in age from 22 to 45 years, comprised two samples: 148 postnatal women (22 to 44 years) and 148 controls (22 to 45 years). Five sets of instruments were used to collect data: the Demographic Data Form, the Perceived Stress Scale, the Interpersonal Support Evaluation List, the Coopersmith's Self-Esteem Inventory, and the Beck Depression Inventory. Although the postnatal group tended to have a higher rate of depression, the difference was not statistically significant. No significant differences in stress, social support, self-esteem or depression were found between these two groups. However, postnatal women reported significantly higher somatic symptoms of depression than controls. Results of the stepwise multiple regression indicated that the best subset to predict postpartum depression was self-esteem, stress, postnatal complication and work status. The best subset to predict depression of controls included self-esteem, social support, socioeconomic status and stress. Our data indicate that the psychosocial health status of postnatal women is not significantly different from the controls, although the postnatal women complain more about the loss of bodily functions. The possible explanations deserve further research.

Adult↗
PubMed2000

Randomized, double-blind comparison of irbesartan and enalapril for treatment of mild to moderate hypertension.

BACKGROUND: Irbesartan is a newly developed angiotensin II receptor antagonist. Its antihypertensive efficacy and safety in Taiwanese patients with mild to moderate hypertension remains to be determined. METHODS: This was a multicenter, double-blind, randomized, parallel group study. One hundred and sixteen patients from three centers were enrolled. After a placebo lead-in period of 14 days, 55 patients (24-75 years-of-age) who had a mean seated diastolic blood pressure of 95 to 110 mmHg were randomized to once-daily treatment with irbesartan 150 mg or enalapril 10 mg. Doses were doubled at week 4 if trough seated diastolic blood pressure was 90 mmHg or more. Trough blood pressure was measured at zero, two, four and eight weeks of treatment. RESULTS: Both treatments lowered blood pressure with no significant difference in efficacy between treatment groups. Irbesartan 150 mg to 300 mg provided reductions in trough seated systolic and diastolic blood pressures at week 8 of -16.5 mmHg and -7.2 mmHg, respectively, with 36% of patients having a favorable response. Similarly, enalapril 10 mg to 20 mg reduced systolic and diastolic blood pressure by -10.6 mmHg and -5.0 mmHg, respectively, with a response rate of 43%. Headache, malaise and dizziness were the major adverse reactions observed in both groups. The incidence of drug-related cough was significantly higher with enalapril (18%) than with irbesartan (0%). CONCLUSIONS: Irbesartan 150 mg to 300 mg once daily was as effective in lowering blood pressure as enalapril 10 mg to 20 mg once daily. Both irbesartan and enalapril were well tolerated, while there was a significantly lower incidence of cough with irbesartan compared with enalapril.

Adult↗
PubMed2000

Neonatal fungemia caused by Hansenula anomala: a case report.

Hansenula anomala, an ascosporogenous yeast of the class Ascomycetes, is a free-living organism isolated from the environment. It is also a part of the normal or transient flora of the human throat and alimentary tract. It has been recognized as an opportunistic pathogen and its infection is very rare. A premature infant, a victim of right femoral osteomyelitis and right hip arthritis caused by oxacillin-resistant Staphylococcus aureus, was found to have developed H. anomala fungemia just before the initiation of the antimicrobial therapy with teicoplanin. Antifungal agents (fluconazole and amphotericin B) were prescribed for 10 days despite the absence of clinical sign of systemic fungal infection. His general condition remained good, with a subsequent sterile blood culture. The patient was discharged after completing 5 weeks of antimicrobial therapy, and he remained well during follow-up at our outpatient clinics. Here, we also review the risk factors, the clinical presentations, and the therapeutic strategies of H. anomala infection in the literature.

Fungemia↗
PubMed2000

The effect of electroacupuncture on shoulder subluxation for stroke patients.

In this study, we evaluated the effect of electroacupuncture on shoulder subluxation for stroke patients. Twenty hemiplegic patients with shoulder subluxation were randomly and equally divided into two groups. The subjects in the control group received conventional therapy, and the subjects in the study group were treated with electroacupuncture and conventional therapy for four weeks. The visual analog scale (VAS) for shoulder pain, motor function status, anthropometry, and X-ray assessment were used to evaluate the status of shoulder subluxation before and after treatment. The results indicated that the pain scores decreased in the study groups significantly more than those in the control group. The degrees of shoulder reduction, including the measurement of anthropometry and X-ray assessment in the study group, were more than those of the control group. However, the motor function status showed no significant difference between two groups. It is concluded that electroacupuncture can be an effective adjuvant management in the treatment of shoulder subluxation for stroke patients.

Adolescent↗
PubMed2000

Effect of melatonin on pro-opiomelanocortin mRNA expression in arcuate nucleus of rat hypothalamus.

AIM: To observe altered expression of pro-opiomelanocortin (POMC) mRNA localized in neurons in the arcuate nucleus of rat hypothalamus following exogenous administration of melatonin. METHODS: The experimental animals were divided into two groups injected i.p. with melatonin 90 mg.kg-1 and vehicle at 12 h interval (9:00 am and 9:00 pm). Twelve hours after the last injection, the rat brains were processed for coronal sections and nonradioactive in situ hybridization histochemistry technic was used. The integral optical density (IOD) and mean optical density (OD) of the stained brain sections were measured using the computer-assisted image processing technique. RESULTS: The POMC mRNA expression in the arcuate nucleus showed obvious enhancement in the brain sections of rats treated with melatonin. The IOD and OD values in the hypothalamic arcuate nucleus area were increased significantly (P < 0.01, P < 0.05 respectively) with melatonin treatment. CONCLUSION: Melatonin may enhance the POMC mRNA expression in the arcuate nucleus of rat hypothalamus.

Animals↗
PubMed2000

[Melatonin influences the release of endogenous opioid peptides in rat periaqueductal gray].

The present study was undertaken to explore central mechanisms underlying the analgesic effect of melatonin. Push-pull perfusion technique and radioimmunoassay were used to observe the changes in the contents of beta-endorphin (beta-Ep) and leucine-enkephalin (L-EK) in the perfusate from the rat periaqueductal gray (PAG) after administration of melatonin. 30 50 min after an intraperitoneal injection of melatonin (110 mg/kg), the beta-Ep content in the perfusate was increased significantly, while the L-EK content was not changed. Pain threshold was measured using the warm water tail-flick test during the push-pull perfusion of the PAG. It was found that the rat pain threshold was increased significantly 40 min after the intraperitoneal injection of melatonin (110 mg/kg). The results suggest that melatonin may promote the release of beta-Ep in the PAG, which may be one of the mechanisms of the analgesic effect of melatonin.

Analgesics, Opioid↗
PubMed2000

Melatonin attenuates the intensity of beta-endorphin immunoreactivity in the arcuate nucleus of rat hypothalamus.

The present study was undertaken to observe the effect of exogenously administered melatonin on the intensity of beta-endorphin (beta-Ep) immunoreactivity of the neuron in the arcuate nucleus of rat hypothalamus with an aim to explore the possible mechanisms of the analgesic effect of melatonin. The experimental rats were divided into two groups, one injected intraperitoneally with melatonin (110 mg/kg) and the other with only a vehicle. One hour after injection, the brain was processed for coronal sections, which were stained with immunohistochemical ABC technique. The integral optical density (IOD) and mean optical density (OD) of the stained sections were measured with a computer-assisted image-processing and analytical system. beta-Ep immunoreactivity was much decreased in the sections treated with melatonin and the IOD and OD were also decreased significantly (P<0.01; P<0.05). The above results suggest that melatonin may result in a decrease of beta-Ep content in the arcuate nucleus, as a result of increased beta-Ep release induced by administration of melatonin. It is likely that the analgesic effect of melatonin may be in part mediated by the release of beta-endorphin from the arcuate nucleus.

Analgesics, Non-Narcotic↗
PubMed1999

Targeting human papillomavirus type 16 E7 to the endosomal/lysosomal compartment enhances the antitumor immunity of DNA vaccines against murine human papillomavirus type 16 E7-expressing tumors.

DNA vaccination is an attractive approach for tumor immunotherapy because of its stability and simplicity of delivery. Advances demonstrate that helper T cell responses play a critical role in initiating immune responses. The aim of the current study is to test whether targeting HPV-16 E7 to the endosomal/lysosomal compartment can enhance the potency of DNA vaccines. We linked the lysosome-associated membrane protein 1 (LAMP-1) to HPV-E7 to construct a chimeric DNA, Sig/E7/LAMP-1 DNA. For in vivo tumor prevention experiments, mice were vaccinated with E7 DNA or Sig/E7/LAMP-1 DNA via gene gun, followed by tumor challenge. For in vivo tumor regression experiments, mice were first challenged with tumor cells and then vaccinated with E7-DNA or Sig/E7/LAMP-1 DNA. Intracellular cytokine staining with flow cytometry analysis, cytotoxic T lymphocyte (CTL) assays, enzyme-linked immunoabsorbent assay (ELISA), and enzyme-linked immunospot (ELISPOT) assays were used for in vitro E7-specific immunological studies. In both tumor prevention and tumor regression assays, Sig/E7/LAMP-1 DNA generated greater antitumor immunity than did wild-type E7 DNA. In addition, mice vaccinated with Sig/E7/LAMP-1 DNA had greater numbers of E7-specific CD4+ helper T cells, higher E7-specific CTL activity, and greater numbers of CD8+ T cell precursors than did mice vaccinated with Sig/E7 or wild-type E7 DNA. Sig/E7 generated a stronger E7-specific antibody response than did Sig/E7/LAMP-1 or wild-type E7 DNA. Our results indicate that linkage of the antigen gene to an endosomal/lysosomal targeting signal may greatly enhance the potency of DNA vaccines.

Animals↗
PubMed1999

Synthesis and structure-activity relationships of potential anticancer agents: alkylcarbamates of 3-(9-acridinylamino)-5-hydroxymethylaniline.

A series of potential 9-anilinoacridine antitumor agents, 3-(9-acridinylamino)-5-hydroxymethylaniline (AHMA) derivatives with monosubstituent at C4' and disubstituents at C4' and C5' of the acridine ring and their alkylcarbamates, were synthesized for evaluation of their antitumor activity. A structure-activity relationship (SAR) study showed that the AHMA-alkylcarbamates were more potent than their corresponding parent AHMA compounds. In addition, the cytotoxicity of the AHMA-alkylcarbamate decreased with increasing length and size of the alkyl function. Among these compounds, AHMA-ethylcarbamate (18) and 4'-methyl-5'-dimethylaminoethylcarboxamido-AHMA-ethylcarb amate (34) possess potent cytotoxicity on the inhibition of human leukemic HL-60 cell growth in culture. Further in vivo studies of these compounds displayed significant anticancer therapeutic effects in mice bearing sarcoma 180, Lewis lung carcinoma, and P388 leukemia.

Acridines↗
PubMed1999

Comparison of ventricular pressure relaxation assessments in human heart failure: quantitative influence on load and drug sensitivity analysis.

OBJECTIVES: We contrasted various methods for assessing ventricular pressure decay time constants to test whether sensitivity to slight data instability or disparities between model-assumed and real decay are systematically altered by cardiac failure. We hypothesized that such discrepancies could result in apparent increased relaxation sensitivity to load and drug stimulation. BACKGROUND: Deviation of relaxation behavior from model-assumed waveforms may be worsened by failure, enhancing instability and apparent load and drug sensitivity of commonly used indexes. METHODS: Pressure-volume relations were measured in patients with normal (n = 14), hypertrophic (hypertrophic cardiomyopathy [HCM], n = 15) and dilated-myopathic (dilated cardiomyopathy [DCM], n = 37) hearts before and during preload reduction or inotropic stimulation. Relaxation parameters (monoexponential [ME] model assuming zero-T(in) or non-zero-T(D), T(F) asymptote:, hybrid logistic-T(L), linear-T(LR), and pressure halftime-T(1/2)) were contrasted regarding sensitivity to slight data range manipulation and loading or drug changes. RESULTS: In DCM, T(D) and T(F) prolonged 15% to 25% (p < 0.0001) by deletion of only 1-2 data points, whereas this had minimal effect on controls or HCM. This stemmed from systematic deviation of relaxation from an ME decay in DCM. T(1/2) and T(in) were highly sensitive to pure pressure offsets, whereas T(L) was most stable to both manipulations in all hearts. As a result, T(D) and T(F) appeared to be much more sensitive to systolic load in DCM than T(1/2) or T(L) and disproportionately sensitive to increased cyclic adenosine monophosphate (cAMP). CONCLUSIONS: Relaxation consistently deviates from an ME decay in DCM resulting in instability and amplified relaxation systolic load or drug dependence of ME-based indexes in failing versus control (or HCM) hearts. The hybrid-logistic method improves quantitative analyses by providing more consistent data fits with all three heart types.

Adult↗
PubMed1999

Cardioprotection from ischemia by a brief exposure to physiological levels of ethanol: role of epsilon protein kinase C.

Recent epidemiological studies indicate beneficial effects of moderate ethanol consumption in ischemic heart disease. Most studies, however, focus on the effect of long-term consumption of ethanol. In this study, we determined whether brief exposure to ethanol immediately before ischemia also produces cardioprotection. In addition, because protein kinase C (PKC) has been shown to mediate protection of the heart from ischemia, we determined the role of specific PKC isozymes in ethanol-induced protection. We demonstrated that (i) brief exposure of isolated adult rat cardiac myocytes to 10-50 mM ethanol protected against damage induced by prolonged ischemia; (ii) an isozyme-selective epsilonPKC inhibitor developed in our laboratory inhibited the cardioprotective effect of acute ethanol exposure; (iii) protection of isolated intact adult rat heart also occurred after incubation with 10 mM ethanol 20 min before global ischemia; and (iv) ethanol-induced cardioprotection depended on PKC activation because it was blocked by chelerythrine and GF109203X, two PKC inhibitors. Consumption of 1-2 alcoholic beverages in humans leads to blood alcohol levels of approximately 10 mM. Therefore, our work demonstrates that exposure to physiologically attainable ethanol levels minutes before ischemia provides cardioprotection that is mediated by direct activation of epsilonPKC in the cardiac myocytes. The potential clinical implications of our findings are discussed.

Adhesins, Bacterial↗
PubMed1999

Sustained in vivo cardiac protection by a rationally designed peptide that causes epsilon protein kinase C translocation.

Brief periods of cardiac ischemia trigger protection from subsequent prolonged ischemia (preconditioning). epsilon Protein kinase C (epsilonPKC) has been suggested to mediate preconditioning. Here, we describe an epsilonPKC-selective agonist octapeptide, psiepsilon receptor for activated C-kinase (psiepsilonRACK), derived from an epsilonPKC sequence homologous to its anchoring protein, epsilonRACK. Introduction of psiepsilonRACK into isolated cardiomyocytes, or its postnatal expression as a transgene in mouse hearts, increased epsilonPKC translocation and caused cardio-protection from ischemia without any deleterious effects. Our data demonstrate that epsilonPKC activation is required for protection from ischemic insult and suggest that small molecules that mimic this epsilonPKC agonist octapeptide provide a powerful therapeutic approach to protect hearts at risk for ischemia.

Amino Acid Sequence↗
PubMed1999

RACK1, a protein kinase C anchoring protein, coordinates the binding of activated protein kinase C and select pleckstrin homology domains in vitro.

The pleckstrin homology (PH) domain, identified in numerous signaling proteins including the beta-adrenergic receptor kinase (betaARK), was found to bind to various phospholipids as well as the beta subunit of heterotrimeric G proteins (Gbeta) [Touhara, K., et al. (1994) J. Biol. Chem. 269, 10217-10220]. Several PH domain-containing proteins are also substrates of protein kinase C (PKC). Because RACK1, an anchoring protein for activated PKC, is homologous to Gbeta (both contain seven repeats of the WD-40 motif), we determined (i) whether a direct interaction between various PH domains and RACK1 occurs and (ii) the effect of PKC on this interaction. We found that recombinant PH domains of several proteins exhibited differential binding to RACK1. Activated PKC and the PH domain of beta-spectrin or dynamin-1 concomitantly bound to RACK1. Although PH domains bind acidic phospholipids, the interaction between various PH domains and RACK1 was not dependent on the phospholipid activators of PKC, phosphatidylserine and 1, 2-diacylglycerol. Binding of these PH domains to RACK1 was also not affected by either inositol 1,4,5-triphosphate (IP(3)) or phosphatidylinositol 4,5-bisphosphate (PIP(2)). Our in vitro data suggest that RACK1 binds selective PH domains, and that PKC regulates this interaction. We propose that, in vivo, RACK1 may colocalize the kinase with its PH domain-containing substrates.

Animals↗
PubMed1999

Characterization of an avian (Gallus gallus domesticus) TCR alpha delta gene locus.

Mammalian TCR delta genes are located in the midst of the TCR alpha gene locus. In the chicken, one large V delta gene family, two D delta gene segments, two J delta gene segments, and one C delta gene have been identified. The TCR delta genes were deleted on both alleles in alpha beta T cell lines, thereby indicating conservation of the combined TCR alpha delta locus in birds. V alpha and V delta gene segments were found to rearrange with one, both or neither of the D delta segments and either of the two J delta segments. Exonuclease activity, P-addition, and N-addition during VDJ delta rearrangement contributed to TCR delta repertoire diversification in the first embryonic wave of T cells. An unbiased V delta 1 repertoire was observed at all ages, but an acquired J delta 1 usage bias occurred in the TCR delta repertoire. The unrestricted combinatorial diversity of relatively complex TCR gamma and delta loci may contribute to the remarkable abundance of gamma delta T cells in this avian representative.

Amino Acid Sequence↗
PubMed1999

Ventricular pacing with premature excitation for treatment of hypertensive-cardiac hypertrophy with cavity-obliteration.

BACKGROUND: Hypertensive left ventricular hypertrophy with supranormal systolic ejection and distal cavity obliteration (HHCO) can result in debilitating exertional fatigue and dyspnea. Dual-chamber pacing with ventricular preactivation generates discoordinate contraction, which can limit cavity obliteration and thereby increase potential ejection reserve. Accordingly, we hypothesized that pacing may improve exercise tolerance long-term in this syndrome. METHODS AND RESULTS: Dual-chamber pacemakers were implanted in 9 patients with exertional dyspnea caused by HHCO. Intrinsic atrial rate was sensed, and ventricular preactivation was achieved by shortening the atrial-ventricular delay. Pacing was on or off for successive 3-month periods (randomized, double-blind, crossover design), followed by 6 additional pacing-on months. Metabolic exercise testing, quality-of-life assessment, and rest and dobutamine-stress echocardiographic/Doppler data were obtained. After 3 months of pacing-on, exercise duration rose from 324+/-133 to 588+/-238 s (mean+/-SD; P=0.001, with 7 of 9 patients improving >/=30%), and maximal oxygen consumption increased from 13.6+/-2.9 to 16.7+/-3.3 mL of O(2). min(-1). kg(-1) (P<0.02). Both parameters were little changed from baseline during the pacing-off period. Improved exercise capacity persisted at 1-year follow-up. Clinical symptoms and activities of daily living improved during the pacing-on period and stayed improved at 1 year, but they were little changed during the pacing-off period. Despite similar basal values, stroke volume (P<0.001) and cardiac output (P<0.02) increased with dobutamine stimulation 2 to 3 times more after 1 year of follow-up as compared with baseline. CONCLUSIONS: Long-term dual-chamber pacing can improve exercise capacity, cardiac reserve, clinical symptoms, and activities of daily living in patients with HHCO. This therapy may provide a novel alternative for patients in whom traditional pharmacological treatment proves inadequate.

Cardiac Output↗
PubMed1999

Nuclear trafficking of Cubitus interruptus in the transcriptional regulation of Hedgehog target gene expression.

Transcriptional activation of Hedgehog (Hh) target genes requires Cubitus interruptus, a 155 kDa cytoplasmic zinc finger protein (Ci155), which in the absence of Hh signaling is processed to form a nuclear repressor (Ci75). We show that Hh signaling reduces phosphorylation of Ci155, and this reduction in turn appears to decrease processing. Blocking processing with proteasome inhibitors or altered Ci proteins, however, is insufficient for activation of Hh targets. We find that Hh signaling increases the rate of Ci155 nuclear import, resulting in significant nuclear accumulation. Even in the absence of signaling, nuclear accumulation of Ci155 suffices for significant induction of Hh targets, and active nuclear export of Ci155 is an essential mechanism for maintenance of the unstimulated state.

Animals↗