Biomedical subjects

C C Chou

Publications and source records attributed to C C Chou.

At least 73 records · Page 4Linked to original sources

PubMed1998

Immunologic changes during immunotherapy in asthmatic children: increased IL-13 and allergen-specific IgG4 antibody levels.

BACKGROUND: The prevalence of allergic diseases such as asthma, allergic rhinitis, and atopic diseases has increased in recent years. Immunotherapy with allergens is a treatment documented to have an effect on regulating cytokine production and allergen-specific antibody production. OBJECTIVE: The aim of this study was to further investigate immunologic changes during immunotherapy and to explore the possible more efficient approach of immunotherapy. METHODS: Asthmatic children receiving house dust mite immunotherapy were followed to learn immunologic parameters such as allergen-specific antibody levels, proliferative response of peripheral blood mononuclear cells, and cytokine change during immunotherapy. RESULTS: The data suggested (1) IgG4 anti-mite antibody increased 8 months after immunotherapy while IgE antibody level remained the same; (2) allergen-induced, in vitro production of certain cytokines such as IL-4 and IL-10 decreased after immunotherapy; (3) IL-13 (which can induce IgG4 and IgE antibody production by B cells) increased after immunotherapy. CONCLUSION: Although this needs more study, IL-13 might play an important role in the generation of IgG4-blocking antibody during immunotherapy.

Adolescent↗

PubMed1998

Age-related changes in blood lymphocyte subsets of Chinese children.

BACKGROUND: Flow cytometric analysis of major lymphocyte populations and their subsets reveals age-related changes in the human cellular immune system. SUBJECTS AND METHODS: Immunophenotypic markers were evaluated in 136 healthy pediatric subjects divided into groups of newborn infants (cord blood), children aged 1 to 2 years, 2 to 5 years, and 6 to 15 years. RESULTS: The percentage of T cells increased gradually with age and the evolution of the percentage of B and NK cells was found to be variable. The percentage of CD4+ cells remains relatively unchanged from infancy to adolescence, but the percentage of CD8+ T cells was lowest at birth and reached maximal levels in the one to two year-old period. The percentage of naive T cells declined with time, but the percentage of memory T cells increased with age. Similar trends were seen in T-cell receptor alphabeta- and gammadelta-bearing T cells. The percentage of CD 11b+CD8+ T cells increased gradually from birth and reached maximal levels from 6 to 15 years old. The expression of the activation markers CD25 and HLA-DR on CD4+ T cells increased with age. The percentage of CD16+CD56- NK cells declined with age, but the evolution of the percentage of CD 16-CD56+ NK cells was variable. The fraction of B cells that expressed CD5 was high at birth (72.9%) and was highest in one to two year olds (73.1%), then declined steadily over time. The CD23 antigen was expressed on 41.9% of B cells at birth and 68.6% during the first to second year, then declined steadily with age. CONCLUSION: These data may serve as a reference range for studies of Chinese pediatric subjects.

Adolescent↗

PubMed1998

Development and use of an enzyme-linked immunosorbent assay to monitor serum and urine acepromazine concentrations in thoroghbreds, and possible changes associated with exercise.

OBJECTIVES: To develop an ELISA that is sensitive and suitable for measurement of immunoreactive acepromazine (ACP) in horse serum and urine and to determine the acute effects of exercise on immunoreactive ACP values in Thoroughbreds. ANIMALS: 12 healthy Thoroughbreds (5 mares, 5 geldings, 2 stallions), aged 2 to 8 years. PROCEDURE: A commercially available antibody and a horseradish peroxidase-conjugated oxime derivative of immunoreactive ACP were used to develop a one-step ELISA. Horses were used in a crossover design study to evaluate possible effects of treadmill exercise on serum and urine ACP concentrations after a single (25 mg) IM injection of the drug. RESULTS: Immunoreactive ACP was detectable at concentrations as low as 50 pg/ml in serum and 100 pg/ml in urine, with intra- and interassay variabilities of 1.1 and 5.2%, respectively. The antibody had some cross-reactivity with a limited number of other phenothiazines. After drug administration, serum ACP immunoreactivity achieved a peak concentration (10.5 ng/ml) within 30 minutes and could be measured up to 48 hours in serum and 120 hours in urine. Although exercise had no significant effect on serum drug concentration, immunoreactive ACP disappeared more quickly (by 48 hours) from the urine of horses in the exercised group. CONCLUSIONS: This one-step ELISA provides a simple and sensitive means to measure immunoreactive ACP in equine serum and urine. The ability to detect drug several days after administration of a low dose of ACP should augment efforts to control illicit use of this drug in performance horses. Potential changes in ACP kinetics after exercise warrant further study.

Acepromazine↗

PubMed1998

A patient with familial Takayasu's arteritis presenting with fever of unknown origin.

Takayasu's arteritis rarely presents with fever of unknown origin. We describe a 14-year-old girl who was admitted with a 2-month history of fever of unknown origin associated with vague pain in her left upper arm. The constitutional symptoms responded to a trial of steroid therapy for suspected collagen-vascular disease, but flared up when the dose was tapered. An asymmetric radial pulse was recognized incidentally during follow-up examination; diagnosis of Takayasu's arteritis was confirmed by Duplex ultrasonography and angiography. Takayasu's arteritis must be considered when evaluating children with fever of unknown origin, especially those with a positive family history. Careful assessment of the peripheral vascular system with better interpretation of limb symptoms should allow early, appropriate treatment to prevent irreversible vascular damage.

Adolescent↗

PubMed1998

Maximization of cholesterol oxidase production by Rhodococcus equi no. 23 By using response surface methodology.

Medium optimization for the production of cholesterol oxidase (EC 1. 1.3.6) by Rhodococcus equi no. 23 was investigated by using response surface methodology and a central composite design. Results revealed that cholesterol and yeast extract had positive effects and the interaction between any two of three factors had no significant effect on cholesterol oxidase production. The optimized medium was the basal medium with the addition of 2.30 g/l cholesterol, 8.18 g/l yeast extract and 4.10 ml/l Tween 80. The peak cholesterol oxidase production (0.242 unit/ml) after 60-72 h cultivation was approx. 4-fold that in control medium.

Carbon↗

PubMed1997

Characterization of potential antagonists of human interleukin 5 demonstrates their cross-reactivity with receptors for interleukin 3 and granulocyte-macrophage colony-stimulating factor.

The ligand-binding alpha-chain of the human interleukin 5 (IL-5) receptor was expressed in its soluble form, lacking the transmembrane and cytoplasmic domains, from recombinant baculovirus. The soluble receptor was used in a scintillation proximity assay to identify two chemical compounds that inhibit binding of human IL-5 to the soluble receptor alpha chain with IC50 of 8 microM and 11 microM. These compounds also inhibited the interaction of human IL-5 with its membrane-bound receptor, composed of the ligand-binding alpha chain and signal-transducing beta chain, and prevented signaling through the receptor. Analysis by surface plasmon resonance and matrix-assisted laser-desorption/ionization mass spectrometry showed that the identified compounds bound irreversibly to the receptor at a 1:1 (mol/mol) ratio, suggesting a covalent interaction with the alpha chain of the human IL-5 receptor. Both compounds also inhibited the interaction of the receptors for interleukin 3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), which are involved in hematopoietic differentiation and activation of immune cells, thus eliminating them as potential therapeutic agents. The inhibition of the structurally closely related receptors for IL-5, IL-3 and GM-CSF by both compounds, while binding of interleukin-4 to its receptor was not affected, suggests that a similar reactive site exists in the ligand-binding domains of the receptors for IL-5, IL-3 and GM-CSF.

Animals↗

PubMed1997

Characterization of interleukin-10 receptor expression on B-cell chronic lymphocytic leukemia cells.

B-cell chronic lymphocytic leukemia (B-CLL) cells accumulate in vivo in the G0/G1 phase of the cell cycle, suggesting that their malignant expansion is due, at least in part, to a delay in cell death. However, the cellular or molecular factors responsible for a delay in B-CLL cell death are unknown. B-CLL cells do express receptors for interferon-alpha (IFN-alpha) and IFN-gamma, and activation of both has been shown to promote B-CLL survival in vitro by preventing apoptosis. The interleukin-10 (IL-10) receptor is another member of the IFN receptor family, but its ligand, IL-10, has been reported to induce apoptosis in B-CLL cells. In the current study, we undertook a biochemical analysis of IL-10 receptor expression on freshly isolated B-CLL cells and characterized the functional responsiveness of IL-10 binding to its constitutively expressed receptor. We show that B-CLL cells bind IL-10 with significant specificity and express between 47 and 127 IL-10 receptor sites per cell, with a dissociation constant in the range of 168 to 426 x 10(-12) mol/L. Ligand binding and activation of the IL-10 receptor expressed on B-CLL cells results in the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and STAT3 proteins. This pattern of STAT protein phosphorylation is identical to IL-10 receptor activation on normal cells and similar to IFN-alpha (STAT1 and STAT3) and IFN-gamma (STAT1) receptor activation in CLL. Further, in consecutive samples of fresh blood obtained from patients with B-CLL cells, the addition of IL-10 inhibited B-CLL proliferation, enhanced B-CLL differentiation, but did not induce apoptosis. Indeed, IL-10, like IFN-gamma, was able to significantly reduce the amount of B-CLL cell death caused by hydrocortisone-induced apoptosis. We conclude that cytokines, which signal through the interferon family of receptors, have comparable functional effects on B-CLL cells.

B-Lymphocytes↗

PubMed1997

Cloning, expression and CNS distribution of Kv4.3, an A-type K+ channel alpha subunit.

A full-length K+ channel cDNA of Kv4.3, with an open reading frame of 611 amino acids, was isolated from rat hippocampus. Functional expression of Kv4.3 cDNA in Xenopus oocytes revealed an A-type K+ channel. In the central nervous system, Kv4.3 is most prominently expressed in the retrosplenial cortex, medial habenula, anterior thalamus, hippocampus, cerebellum, as well as lateral geniculate and superior colliculus, which are important for vision. The abundant expression of Kv4.3 in many CNS neurons supports its important role as a major component of subthreshold A currents in the control of action potentials and thus neuronal excitability.

Amino Acid Sequence↗

PubMed1997

Expression, purification, and crystallization of two isozymes of 6-phosphoglucose isomerase of Bacillus stearothermophilus.

Two isozymes of 6-phosphoglucose isomerase (phosphoglucose isomerase A & phosphoglucose isomerase B), isolated from Bacillus stearothermophilus, have been overexpressed in Escherichia coli strain DF2145 and purified to homogeneity. Crystals of both isozymes have been obtained by the vapor diffusion method. The crystals of phosphoglucose isomerase A have unit cell dimensions a = b = 132.0 A, c = 183.6 A, and diffract to about 2.8 A resolution. An analysis of the reflection data indicates that the crystal system is hexagonal, space group P6122 or P6522. The crystals of phosphoglucose isomerase B complexed with 6-phosphogluconate belong to the orthorhombic space group I222 (or I212121), with cell dimensions a = 75.1 A, b = 95.7 A, c = 171.5 A, and diffract to a resolution of 2.3 A. These crystals promise to yield more detail for the substrate recognition and higher resolution structures of 6-phosphoglucose isomerase.

Crystallization↗

PubMed1997

Antiapoptotic effect of ras in the apoptosis induced by serum deprivation and exposure to actinomycin D.

Serum deprivation or exposure of NIH 3T3 cells to actinomycin D (0.25-1.0 microgram/ml; 1 h) was associated with the accumulation of numerous apoptotic cells, as identified by their condensed nuclei and the decrease in cell size. In contrasts, v-H-ras-transformed NIH 3T3 cells were found to be resistant to this apoptosis induction. When v-H-ras-transformed cells were first pretreated for 24 h with 50 microM mevastatin, an agent which is known to be capable to deactivate the ras function, cell viability decreased and apoptotic cells became abundant (approximately 60-80%) 72 h after serum deprivation or exposure to actinomycin D. During the serum deprivation of NIH 3T3 cells, appearance of the apoptotic cells was preceded by G1 phase arrest. Accumulation of cells in the G1 phase was also observed in v-H-ras-transformed cells 24 h after serum deprivation. At later times (48-72 h), v-H-ras-transformed cells seemed to be capable of breaking through the G1 arrest and were then found to be distributed normally in the cell cycle.

3T3 Cells↗

PubMed1997

The effect of accurate patient screening on the cost-effectiveness of case management programs.

Case management programs are expensive and therefore require careful screening of enrollees to ensure cost-effectiveness. Screening tools, however, are imperfect, with positive predictive values usually below 50%. This article examines the relationship between the accuracy of the screening tools and the cost-effectiveness of case management. Using data from a Medicare health maintenance organization (HMO), we develop an optimized 5-question screening tool. We then simulate the use of this screening tool and its impact on the cost-effectiveness of several hypothetical case management programs. The article demonstrates that even screening tools with only 20-30% positive predictive value could turn a case management program into a cost-effective program.

Activities of Daily Living↗

PubMed1997

Pulmonary biology of anti-interleukin 5 antibodies.

Interleukin-5 (IL-5) is a critical cytokine for the maturation of eosinophil precursors to eosinophils in the bone marrow and those eosinophils then accumulated in the lungs during asthma. We have studied anti IL-5 antibodies on allergic responses in mice, guinea pigs and monkeys and are extending this experiment into humans with a humanized antibody. In a monkey model of pulmonary inflammation and airway hyperreactivity, we found that the TRFK-5 antibody blocked both responses for three months following a single does of 0.3 mg/kg, i.v. This antibody also blocked lung eosinophilia in mice by inhibiting release from the bone marrow. To facilitate multiple dosing and to reduce immunogenicity in humans, we prepared Sch 55700, a humanized antibody against IL-5. Sch 55700 was also active against lung eosinophilia in allergic monkeys and mice and against pulmonary eosinophilia and airway hyperresponsiveness in guinea pigs. Furthermore, as opposed to steroids, Sch 55700 did not cause immunosuppression in guinea pigs. Studies with this antibody in humans will be critical to establishing the therapeutic potential of IL-5 inhibition.

Animals↗

PubMed1997

Purification and characterization of a 94 KD high molecular weight allergen from house dust mite, Dermatophagoides pteronyssinus.

House dust mite allergens from Dermatophagoides pteronyssinus is an important cause of severe allergic asthma and rhinitis in many countries. Although several low to medium molecular weight allergens had been well characterized, limited studies on the high molecular weight IgE-binding components were reported. In this study, a 94 kD high molecular weight allergen from crude mite body extract of D. pteronyssinus was purified and characterized. Monoclonal antibody (mAb) affinity chromatography and high performance liquid chromatography were used to purify 94 kD allergen. Its antigenicity and allergenicity were confirmed by in vitro and in vivo studies. Two mAbs 2205-3.45 and 2220-7.25 specific to 94 kD high molecular weight component of D. pteronyssinus were generated. The epitopes recognized by these mAbs were species-specific. Enzyme-linked immunosorbent assay (ELISA) of IgE reactivity in the sera from 40 asthmatic children allergic to D. pteronyssinus showed that 37.5% of them had significantly higher optical density values (range 0.011 to 0.452) than normal (range 0.013 to 0.035). In in vivo skin test showed that 9 out of 20 (45%) asthmatic children were positive to 94 kD allergen. The results demonstrate that 94 kD high molecular weight component is an important allergen existing in house dust mite in Taiwan.

Allergens↗

PubMed1997

Immune effector cells induced by complete Freund's adjuvant exert an inhibitory effect on antigen-specific type 2 T helper responses.

BACKGROUND: It has been well documented that environmental factors such as antigenpresenting cells and related cytokines could affect the development of T helper cells. OBJECTIVE: The purpose of this study is to investigate the effect of different adjuvants on T cell development. METHODS: Ovalbumin (OVA) combined with aluminum hydroxide (Alum) plus pertussis toxin (PT) or complete Freund's adjuvant (CFA) were used to sensitize mice; the production of IgG and IgE anti-OVA antibodies was then followed. In addition, OVA-specific proliferative responses and cytokine production by spleen cells were also investigated. RESULTS: The data showed that the adjuvants themselves could modify the pattern of immune response: (1) IgG2a anti-OVA antibody was higher in mice sensitized with OVA + CFA compared to that of mice sensitized with OVA + Alum + PT; (2) the ratio of IFN-gamma/IL-4 produced by OVA-stimulated spleen cells was higher in mice sensitized with OVA + CFA than that of mice sensitized with OVA + Alum + PT: (3) increased percentage of gamma delta T cells was noted in the peritoneal exudate cells of OVA + CFA immunized mice; and (4) the immune response of mice sensitized with OVA + Alum + PT was inhibited by the adoptively transferred ascitic cells from OVA + CFA immunized mice. CONCLUSION: In general, the data suggested higher IgG2a and the ratio of IFN-gamma/IL-4 was noted in mice sensitized with OVA + CFA. Further elucidation of the regulatory mechanism of allergen-specific T helper cells development and exploration of possible agents for immunotherapy might shed light on the management of atopic diseases.

Aluminum Hydroxide↗

PubMed1997

Latex allergy in hospital employees.

The purpose of this study was to investigate the prevalence and risk factors of latex-allergy in hospital personnel and the presence of latex-specific IgE in a latex-allergic group in Taiwan. A total of 1,021 hospital employees were initially screened for latex allergy with a questionnaire, which included sex, age, job categories, number of years of employment, daily working hours, frequency of latex glove wearing, symptoms of immediate reactions to latex gloves and history of previous atopic diseases. Among them, 70 hospital employees (6.8%; 95% confidence interval 1.9%-11.8%) had symptoms associated with glove wearing. The frequencies in different job categories were 28.3% of surgical nurses, 9.2% of surgeons, 5.8% of regular floor nurses, 5.2% of technicians, 4.6% of physicians, and 4.5% of laboratory researchers. The symptoms were significantly related to the frequency of latex glove exposure, surgical work, current hand eczema and history of atopic dermatitis. In contrast, the number of years of employment, daily working hours and previous history of hand eczema were not correlated with the symptoms of latex allergy. Latex-specific IgE was assayed by the dot blot method in 36 hospital employees of the latex allergic group (positive rate, 55.6%). We concluded that the prevalence of latex-allergy among hospital personnel was 6.9% and certain predisposing factors such as atopic dermatitis, current hand eczema ad surgical work may play a critical role in triggering and aggravating the symptoms.

Adult↗

PubMed1997

CATCH 22: deletion of locus 22q11 in velocardiofacial syndrome, DiGeorge anomaly, and nonsyndromic conotruncal defects.

DiGeorge anomaly (DGA) and velocardiofacial syndrome (VCFS) are frequently associated with monosomy of chromosomal subband 22q11. It is not clear whether individuals who present with only some of the features (e.g., isolated hypoparathyroidism or conotruncal defects) of these conditions also have the same deletion. In a prospective study of 30 children from 1994 to 1996, we used both high-resolution banding and fluorescence in situ hybridization (FISH) to assess the deletion status of children with a wide range of DGA-like or VCFS-like clinical features. Microdeletion of the chromosomal subband 22q11.22 was detected in 17 children by high-resolution banding and in two additional children with conotruncal defect (CTD) who had submicroscopic deletions proved by FISH analyses. Of the patients with microscopical deletion (n = 17), only six had classical DGA (n = 4) or VCFS (n = 2) phenotypes. The other 11 had various forms of congenital heart defects as the only presenting signs of deletion. One patient with DGA stigmata had another chromosomal aberration of monosomy 10p13. Only 10 patients were found to have neither cytogenetic nor molecular abnormalities. Therefore, it appeared that the majority, if not all, of the DGA and VCFS patients with the 22q11 deletion were identifiable using FISH with the single N25 (D22S75) probe. It would also be advisable that children with isolated CTD should be carefully examined to detect the other morphologic abnormalities of DGA and VCFS, or CATCH 22 (cardiac defects, abnormal facies, thymic hypoplasia/aplasia, cleft palate, hypocalcemia, and 22q11 deletion). Once these abnormalities are found, a molecular cytogenetic analysis for the so-called 22q11 region is indicated. Because of other associated chromosomal findings, routine or high-resolution cytogenetic analysis should be performed on patients with suspected CATCH 22.

Abnormalities, Multiple↗

PubMed1997

Application of cryoablation in the management of prostate cancer.

BACKGROUND: Radical prostatectomy is the most common and effective therapy for localized prostate cancer. But in addition to its surgical complications, even highly selected series carry a positive margin rate of 35 to 50%. Radiotherapy is another alternative for prostate cancer, but following radiotherapy there have been high positive biopsies reported. Cryosurgery, defined as in situ freezing and hence, devitalization of neoplastic tissues, has currently raised the interest of urologists in the management of localized prostate cancer or failed radiotherapy. MATERIAL: Five patients underwent transperineal cryosurgery of prostate in Chang Gung Memorial Hospital. Among them, three cases were stage D, one stage B and another failed radiotherapy of stage C prostate cancer. All patients received hormone therapy too. RESULTS: PSA declined in 3 patients and biopsies showed intraductal neoplasia. All 5 patients suffered from urine incontinence and one persisted. No mortality has been reported. CONCLUSION: Cryoablation of the prostate is an alternative for treatment of prostate cancer.

Aged↗

PubMed1997

Nutritional factors that affect the production of cholesterol oxidase by Rhodococcus equi no. 23.

Some nutritional factors affecting the production of cholesterol oxidase (COX) by Rhodococcus equi no. 23 were investigated. Cholesterol and yeast extract respectively were the best carbon source and nitrogen source for the COX production. The optimum concentration of cholesterol and yeast extract was found to be about 0.1% and 0.4-0.5% (w/v) respectively. In addition, NH4Cl, NaCl and Tween 80 also exhibited enhancing effects on COX production, being maximal at 0.1% (w/v), 0.2% (w/v) and 1.0% (v/v) respectively. Moreover, optimal enzyme production occurred in medium that had an initial pH of 7.0.

Biotechnology↗