Biomedical subjects

C C Chen

Publications and source records attributed to C C Chen.

At least 73 records · Page 4Linked to original sources

PubMed2001

Water-soluble glycosides from Ruta graveolens.

An EtOH extract of the dried aerial parts of Ruta graveolens was suspended in water and then partitioned with EtOAc. Three new glycosides, 3'-sinapoyl-6-feruloylsucrose (4), methylcnidioside A (5), and methylpicraquassioside A (6), together with four known glycosides, 3',6-disinapoylsucrose (1), cnidioside A (2), rutin, and picraquassioside A (3), were isolated from the water-soluble part. Their structures were elucidated by interpretation of IR, MS, and 1D and 2D NMR spectra and comparison with literature data.

China↗

PubMed2001

Three xanthones and a benzophenone from Garcinia mangostana.

Investigation of the constituents of Garcinia mangostana has led to the isolation of four new compounds: three minor xanthones, garcimangosone A (1), garcimangosone B (2), and garcimangosone C (3), and a benzophenone glucoside, garcimangosone D (4). The structures of these four compounds were established by spectral (NMR and MS) and chemical methods.

Benzophenones↗

PubMed2001

Two phenanthraquinones from Dendrobium moniliforme.

Two phenanthraquinones were isolated from the stems of Dendrobium moniliforme. They were identified by interpretation of spectral data as 2,6-dimethoxy-1,4,5,8-phenanthradiquinone and 5-hydroxy-3,7-dimethoxy-1,4-phenanthraquinone, named moniliformin (1) and denbinobin (2), respectively. This is the first report of compound 1, which possesses a novel 1,4,5,8-diquinone moiety in the phenanthraquinone skeleton. Compound 2 showed potent antiinflammatory effects in vitro.

Animals↗

PubMed2001

Exposure to a high concentration of mite allergen in early infancy is a risk factor for developing atopic dermatitis: a 3-year follow-up study.

The cause of allergy is multi-factorial, and the development of an allergic disease seems to be the result of an interaction between genetic and environmental factors. The goal for preventing the development of allergic diseases is to avoid sensitization to allergens. The aim of this work was to study whether or not exposure to environmental allergens early in infancy would influence the occurence of various allergic diseases in later life. On an annual basis, a total of 931 healthy newborns were followed-up until they reached 3 years of age. The occurence of allergic diseases was recorded by trained medical students during visits. Measurement of Dermatophagoides pteronyssinus (Der p 1) concentration in house dust was performed when each baby was 18 and 36 months old. Total and specific immunoglobulin E (IgE) antibodies against Der p 1, cow's milk, and egg white were evaluated at birth and at 18 months of age. The following results were obtained: at 3 years of age, 10.4% had bronchial asthma (BA), 21.4% atopic dermatitis (AD), 7.0% urticaria, and 46.8% had experienced wheezing; higher family allergy scores led to a higher incidence of AD (p=0.0012); exposure to a mite allergen concentration of 1 microg/g of dust may be associated with a higher incidence of AD (p=0.0156); the presence of Der p 1 IgE antibody at 18 months of age was associated with a higher incidence of BA (p=0.0001); and children sensitized to egg whites at 18 months of age had an increased risk of developing AD at 3 years of age (p=0.0187). Hence, early exposure to mite allergen is a risk factor for the development of atopic dermatitis, but seems not to be related to the development of bronchial asthma. Early sensitization to egg whites increases the risk of developing AD. The early detection of serum Der p 1 IgE antibody is associated with a higher incidence of bronchial asthma.

Age Factors↗

PubMed2001

Brain dysfunction explored by long latency reflex: a study of adrenomyeloneuropathy.

OBJECTIVES: We can assess brain function by measuring the cortical relay time (CRT) of long latency reflex (LLR) of hand muscle. We would study if measurement of CRT of LLR can explore the brain involvement of adrenomyeloneuropathy (AMN). METHODS: Two AMN patients were included in the study. Both of them had spastic gait and mild sensory deficits but normal mental function. The LLRs were provoked at the first dorsal interosseous muscle by electrical stimulation of the middle finger. We measured the latency of LLR and its CRT. RESULTS: Delayed LLR and prolonged CRT were noted in AMN patients, even though the magnetic resonance imaging of brain did not show any significant abnormalities. CONCLUSIONS: Measuring CRT of LLR reveals brain involvement of AMN patients, and it is an adjunct in the assessment of brain function though without specific anatomic diagnosis.

Adrenoleukodystrophy↗

PubMed2001

Effect of prophenoloxidase expression knockout on the melanization of microfilariae in the mosquito Armigeres subalbatus.

Melanization is an effective defence reaction used by mosquito hosts to kill malarial and filarial worm parasites. Although phenoloxidase (PO) has long been considered to be the key enzyme in the biosynthesis of melanotic material in insects, there is no direct evidence verifying its role in parasite melanization. To elucidate the role of PO in the melanization of microfilariae (mf) by mosquitoes, a double subgenomic Sindbis (dsSIN) recombinant virus was used to transduce Armigeres subalbatus mosquitoes with a 600 base antisense RNA targeted to the highly conserved copper-binding region of an Ar. subalbatus PO gene. Compared with controls, haemolymph PO activity in mosquitoes transduced with antisense RNA was significantly reduced. When these mosquitoes were challenged with Dirofilaria immitis mf, the melanization of mf was almost completely inhibited. These data verify that PO is an essential component of the biochemical pathway required for the melanization of parasites, and that the dsSIN expression system represents a useful tool in the functional analysis of endogenous gene expression in mosquitoes.

Animals↗

PubMed2001

Causes of death of patients with substance dependence: a record-linkage study in a psychiatric hospital in Taiwan.

AIMS: The causes of death among a series of patients with substance dependence were investigated. SETTING: A psychiatric teaching hospital in Taipei, Taiwan (Taipei City Psychiatric Center). PARTICIPANTS: A total of 1698 patients with various diagnostic categories of substance dependence, who had been admitted to TCPC for detoxification were followed-up from 1985 to 1996. DESIGN: A record-linkage study was performed using the patient's national identification number to link between TCPC chart records and the mortality file compiled by the National Department of Health. Risk factor analyses for mortality included socio-demographic data, clinical diagnosis and cause of death. FINDINGS: A total of 141 patients died during the study period. Among them, 83 had a diagnosis of alcohol dependence, 41 of heroin dependence and the remaining 17 cases of sedative, glue or hallucinogen dependence. The annual mortality rate of patients with heroin dependence was 1.94%. Accidental death is the leading cause of death among patients with heroin dependence. However, the patients with alcohol dependence had a higher mortality risk than those with heroin dependence (relative hazard = 1.91, p < 0.001) in this study. The proportion of non-violent death was significantly higher among the patients with alcohol dependence than those with heroin dependence (p < 0.005). CONCLUSION: The causes of death among patients with substance dependence found in this Taiwanese series were very similar to those reported in the western literature. However, differences included the absence of death among heroin addicts due to HIV-related disease and a markedly high percentage of alcoholic patients who died of liver diseases.

Accidents↗

PubMed2001

Molecular cloning of a second prophenoloxidase cDNA from the mosquito Armigeres subalbatus: prophenoloxidase expression in blood-fed and microfilariae-inoculated mosquitoes.

Melanization constitutes an important component in various aspects of insect life, including cuticular sclerotization, egg-shell tanning, melanization of parasites and wound healing. Recently, a cDNA encoding prophenoloxidase (pro-PO), a key enzyme in the biosynthesis of melanotic material in insects, was cloned from microfilariae (mf)-inoculated mosquitoes, Armigeres subalbatus. However, results of Northern blot analyses indicated that two pro-POs might be present in Ar. subalbatus and these pro-POs might be responsible for two distinct physiological functions, egg-shell tanning and melanization of parasites. Subsequently, the second pro-PO cDNA (As-pro-PO II) was cloned from blood-fed Ar. subalbatus by rapid amplification of cDNA ends polymerase chain reaction. The 2210 bp As-pro-PO II cDNA contains a 41 bp 5'-non-coding region, a 2064 bp open reading frame and a 105 bp 3'-non-coding region. A hydrophobic signal peptide for endoplasmic reticulum targeting is not found in the N-terminal region. The deduced amino acid sequence of As-pro-PO II shares a high degree of identity (81.5%) with that of the As-pro-PO I obtained from mf-inoculated Ar. subalbatus. Both Northern blot and reverse transcription polymerase chain reaction analysis demonstrated that these two mosquito pro-POs are persistently expressed in mosquito haemocytes and not in fat body, midgut, or ovaries. The expression of As-pro-PO I and As-pro-PO II in mosquitoes is associated with melanization of mf and blood feeding, respectively.

Amino Acid Sequence↗

PubMed2001

Molecular cloning of two prophenoloxidase genes from the mosquito Aedes aegypti.

The biosynthesis of melanotic materials is an important process in the life of a mosquito. Melanin production is critical for many diverse processes such as egg chorion tanning, cuticular sclerotization, and melanotic encapsulation of metazoan parasites. Prophenoloxidase plays a critical role in this biochemical cascade. Two cDNAs, one full length and one partial clone, and two genomic clones encoding prophenoloxidase (pro-PO) were isolated from the yellow fever mosquito, Aedes aegypti. The full-length cDNA, pAaProPO1, is 2286 bp long with a 2055 bp open reading frame encoding a 685 amino acid protein that shares 89% identity with Armigeres subalbatus pro-PO. It contains two putative copper binding domains (amino acids 197-243 and 346-423) that are homologous to other insect pro-POs. AaProPO1 messenger RNA (mRNA) was detected by reverse transcription polymerase chain reaction (RT-PCR) only from third-stage larvae and not in adult mosquitoes after blood feeding, during the melanotic encapsulation of Dirofilaria immitis microfilariae or following exposure to bacteria. A 750 bp fragment of the second cDNA (pAaProPO2) was cloned using RT-PCR from mRNA obtained from 14-day postovipostional eggs. AaProPO2 mRNA was not found in any other life stages, and may be in low abundance or transiently expressed. AaProPO2 and AaProPO1 each contain three introns that are 60, 68 and 58 bp and 61, 69 and 59 bp long, respectively, and the intron sequences of these two genes are not similar.

Aedes↗

PubMed2001

A concept analysis of malnutrition in the elderly.

PURPOSE: Malnutrition is a frequent and serious problem in the elderly. Today there is no doubt that malnutrition contributes significantly to morbidity and mortality in the elderly. Unfortunately, the concept of malnutrition in the elderly is poorly defined. The purpose of this paper is to clarify the meaning of malnutrition in the elderly and to develop the theoretical underpinnings, thereby facilitating communication regarding the phenomenon and enhancing research efforts. SCOPE, SOURCES USED: Critical review of literature is the approach used to systematically build and develop the theoretical propositions. Conventional search engines such as Medline, PsyINFO, and CINAHL were used. The bibliography of obtained articles was also reviewed and additional articles identified. Key wards used for searching included malnutrition, geriatric nutrition, nutritional status, nutrition assessment, elderly, ageing, and weight loss. CONCLUSIONS: The definition of malnutrition in the elderly is defined as following: faulty or inadequate nutritional status; undernourishment characterized by insufficient dietary intake, poor appetite, muscle wasting and weight loss. In the elderly, malnutrition is an ominous sign. Without intervention, it presents as a downward trajectory leading to poor health and decreased quality of life. Malnutrition in the elderly is a multidimensional concept encompassing physical and psychological elements. It is precipitated by loss, dependency, loneliness and chronic illness and potentially impacts morbidity, mortality and quality of life.

Aged↗

PubMed2001

Hyperventilation facilitates induction of supraventricular tachycardia: a novel method and the possible mechanism.

INTRODUCTION: Hyperventilation has been demonstrated to alter autonomic function. Sympathomimetic drugs (isoproterenol) and parasympatholytic drugs (atropine) may be needed to facilitate induction of supraventricular tachycardia (SVT). The aim of this study was to test the clinical utility and mechanisms of hyperventilation to facilitate SVT initiation. METHODS AND RESULTS: Fourteen patients with clinically documented SVT (9 AV nodal reentrant tachycardia and 5 AV reciprocating tachycardia) but noninducible during baseline electrophysiologic study were included. Immediately after hyperventilation test (at least 30 respirations/min) for 2 minutes, systolic blood pressure, sinus cycle length, anterograde and retrograde 1:1 conduction, and induced SVT were measured. Arterial blood gas, pH, and heart rate variability before and after hyperventilation were measured. Seven of nine patients with AV nodal reentrant tachycardia and 3 of 5 patients with AV reciprocating tachycardia could be induced immediately after the hyperventilation test. After hyperventilation, anterograde AV and retrograde VA 1:1 conduction were improved, sinus cycle length was decreased, and heart rate variability were decreased in both groups. CONCLUSION: Hyperventilation can facilitate induction of SVT. Improvement of conduction properties and changes of autonomic function are the possible mechanisms.

Accessory Nerve↗

PubMed2001

Mechanisms of transition between double paroxysmal supraventricular tachycardias.

INTRODUCTION: Coexistence of double tachycardias in one patient has been infrequently reported. Furthermore, the mechanisms of transition between double paroxysmal supraventricular tachycardias have not been well studied. METHODS AND RESULTS: Thirty-five patients with two paroxysmal supraventricular tachycardias were studied. Group IA consisted of 3 patients with spontaneous transition between AV reciprocating tachycardia (AVRT) and AV nodal reentrant tachycardia (AVNRT). Group IB consisted of 13 patients without spontaneous transition between AVRT and AVNRT. Group IIA consisted of 5 patients with spontaneous transition between AVNRT and atrial tachycardia (AT). Group IIB consisted of 14 patients without spontaneous transition between AVNRT and AT. The absolute values of differences between the two tachycardia cycle lengths were significantly smaller in patients with than in those without transition between the two tachycardias (25+/-8 msec vs 90+/-46 msec, P < 0.05, IA vs IB; 21+/-25 msec vs 99+/-57 msec, P < 0.01, IIA vs IIB). The cutoff point of 25 msec had 80% positive predictive value for transition between the two tachycardias. Transition between two tachycardias occurred due to a spontaneous premature atrial complex (30%), conduction block at one limb of tachycardia (20%), or tachycardia-induced tachycardia (50%). Absence of transition between two tachycardias might be explained by the absence of a spontaneous premature atrial complex, longer cycle length of the first tachycardia, larger difference between two tachycardia cycle lengths, or induction of each tachycardia under different situations. CONCLUSION: Double supraventricular tachycardias with similar tachycardia cycle lengths are vulnerable to transition between different tachycardias.

Adolescent↗

PubMed2001

Quantitative determination of secoiridoid glucosides in in vitro propagated plants of Gentiana davidii var. formosana by high performance liquid chromatography.

A simple protocol for in vitro mass propagation of Gentiana davidii var. formosana (Gentianaceae) has been developed. Multiple shoot development was achieved by culturing the stem node explants on Murashige and Skoog (MS) medium supplemented with 4.44 microM N6-benzyladenine (BA). The shoots were multiplied by subculturing on MS medium supplemented with 1.07-10.74 microM alpha-naphthaleneacetic acid (NAA) and 8.88 microM BA. Shoots were rooted on MS basal medium supplemented with various auxins. Shoots rooted on growth regulator-free medium were transferred to peat moss:vermiculite mixture and acclimatized in the growth chamber. The contents of gentiopicroside and swertiamarin, the two important secoiridoid glucosides, in different plant material were determined by high performance liquid chromatography (HPLC). The analysis revealed that the content of gentiopicroside and swertiamarin in the aerial and underground parts of G. davidii var. formosana was higher than the marketed crude drug (underground parts of G. scabra) and varied with the age of the plant.

Chromatography, High Pressure Liquid↗

PubMed2001

Vasorelaxing effect of coumarins from Cnidium monnieri on rabbit corpus cavernosum.

Bioassay-directed fractionation led to the identification of four known coumarins, osthole (1), imperatorin (2), xanthotoxin (3), and isopimpinellin (4), from the ethanolic extract of the fruit of Cnidium monnieri (L.) Cusson. In phenylephrine (PE)-precontracted endothelium-intact rabbit corpus cavernosum, all four coumarins exhibited relaxing effect with the IC50 values for compounds 1, 2, 3, and 4 determined to be 2.14 +/- 0.73, 0.85 +/- 0.16, 1.24 +/- 0.45, and 18.4 +/- 8.10 microM, respectively. The four compounds were identified by comparison of their physical data (EIMS, 1H- and 13C-NMR) with those from published reports.

Animals↗

PubMed2001

Isolation of Haemophilus parahaemolyticus in a patient with cryptogenic brain abscess.

Haemophilus parahaemolyticus rarely causes disease in humans. We present the case of a 68-y-old man who suffered from a brain abscess over the right-side thalamus and midbrain. Stereotactic aspirates grew H. parahaemolyticus. No portal of entry for the microorganism was identified in this case. The patient made a good recovery after treatment.

Aged↗

PubMed2001

Wet air oxidation of a direct dye solution catalyzed by CoAlPO4 -5. Performance assessment and kinetic study.

Wet air oxidation (WAO) of a prepared direct dye solution was tested by using the CoAIPO4 -5 catalyst. Addition of CoAIPO4 -5 could effectively improve rate of color removal and the activation energy of color removal could decrease from about 110 kJ/mole to about 75 kJ/mole as the catalyst loading was increased from 0.0 g/L to 3.0 g/L. Performance of WAO on color removal would somewhat increase with catalyst loading at 145 degrees C whereas the effect of catalyst loading was not significant at 135 degrees C. With no addition of CoAlPO4 -5, the chemical oxygen demand (COD) value was low. This was due to difficulty of exactly measuring the true COD value of dye solution if the dye was not degraded. Via CoAIPO4 -5, COD of dye solution could be effectively decreased. The rate of COD removal would increase with catalyst loading, oxygen pressure and reaction temperature. Furthermore, a maximum COD value observed, which was due to catalyzed degradation of dye molecule via CoAlPO4 -5, could be characterized by a consecutive reaction scheme. Kinetic study of color removal is expressed as follows: rate = k x [dye](0.8) x W(0.5) x P(n) (145 degrees C) or rate = k x [dye](0.8) x W(0) x P(n) (135 degrees C); where k means rate constant, [] means concentration, W means catalyst loading, P means oxygen pressure and n means uncertain number.

Aluminum Compounds↗

PubMed2001

Maintenance of mydriasis with one bolus of epinephrine injection during phacoemulsification.

Surgically-induced miosis commonly occurs during cataract extraction surgery, complicating removal of lens cortex and placement of a posterior chamber intraocular lens. To maintain intraoperative mydriasis, one bolus of epinephrine injection was used in our study. The pupillary response to various doses of intracameral epinephrine (0.1 ml of 1:25,000, 1:50,000, 1:100,000, 1:200,000, 1:400,000) was assessed in 60 consecutive patients. The pupil size was measured just prior to the incision, one min after epinephrine injection, after phacoemulsification and after irrigation/aspiration. There was no significant difference among the mean mydriatic responses to the epinephrine concentrations we tested. The 1:400,000 concentration appeared to be as effective as 1:25,000, but two cases of the 1:400,000 group failed to maintain the pupil diameter after irrigation/aspiration. In addition, we found that blood pressure did not elevate after injection of any concentration of epinephrine. We concluded that one bolus of an extremely dilute concentration of epinephrine (i.e., 1:400,000) injection might be effective in maintaining mydriasis during cataract surgery without systemic side effects.

Aged↗

PubMed2001

Role of B cells as antigen-presenting cells in vivo revisited: antigen-specific B cells are essential for T cell expansion in lymph nodes and for systemic T cell responses to low antigen concentrations.

Studies in B cell-deficient mice generated by continuous injection of anti-mu antibodies (muSM) showed that T cell priming in lymph nodes was dependent on antigen presentation by B cells. This concept has recently become controversial since a wide range, from complete deficiency to near normal T cell responses, was reported in studies carried out with B cell-deficient mice generated by gene disruption (muMT). In this study we show that in the absence of B cells, T cell responses are greatly reduced in all the available muMT mouse strains although responses in muMT of the C57BL/6 background (which were used for most studies with muMT) were much more variable and could reach up to 42% of control. In contrast, T cell responses in muMT --> F(1) bone marrow chimeras which have the same phenotype as muMT were totally impaired, suggesting a principle difference between mice developing without B cells (muMT mice) and muSM which are made B cell deficient only after birth. Normal T cell priming was completely restored by reconstitution of muMT and muMT --> F(1) mice with syngeneic B cells. Interestingly, only B cell populations containing antigen-specific B cells were capable of reconstituting T cell responses. Monoclonal B cells taken from Ig transgenic mice could not reconstitute responses to an irrelevant antigen. We also found that B cells were also required for systemic T cell priming when antigen concentrations were limiting but were not required for priming (for T cell help) when mice were immunized with a high antigen dose.

Adoptive Transfer↗