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Biomedical subjects

C Chien

Publications and source records attributed to C Chien.

At least 19 recordsLinked to original sources
PubMed2003

Induction of glutathione S-transferases activities in Drosophila melanogaster exposed to phenol.

Studying the toxic effects of long-term exposing fruit flies to phenol is the object of this study. The induction of the glutathione S-transferases enzymatic activities, the change in the amount of mRNA related to phenol exposure, the change in survival rate of adult fruit flies, and the chemical interaction between phenol and benzene were the problems to be investigated. Glutathione S-transferases were separated by affinity chromatography and the mRNAs levels were quantified by reverse-transcription polymerase chain reaction. Long-term feeding phenol to wild type fruit flies had caused some toxic effects included increasing the resistance to phenol toxicity, lowering the benzene toxicity, and induction of glutathione S-transferases enzymatic activities. But no significant change in the amount of glutathione S-transferases GstD1 and GstD5 mRNAs had occurred. From these results, we concluded that fruit flies could develop resistance to phenol by decreasing its toxicity; phenol was a inducer of glutathione S-transferases; phenol could increase the glutathione S-transferases enzymatic activities by increasing the amount of proteins; phenol exposure could decrease the benzene toxicity; no new glutathione S-transferase isozyme subunit was induced; and the level of GstD1 and GstD5 mRNAs did not significantly increase in phenol-treated strain.

Animals↗
PubMed2001

Fetal behavioural state changes following maternal fluoxetine infusion in sheep.

Clinical depression is diagnosed in 5-15% of women during pregnancy, increasing the risk of negative outcomes. Fluoxetine (FX), a selective serotonin reuptake inhibitor, is prescribed during pregnancy. In adults, FX alters sleep patterns with single doses decreasing total sleep time and rapid eye movement sleep. The effects of FX on sleep in the fetus are unknown. However, 5-hydroxytryptophan, the precursor of serotonin, has been reported to prolong high-voltage (HV) electrocortical (ECoG) activity and increase the incidence of fetal breathing movements (FBM) in the sheep fetus. We hypothesize that FX exposure will decrease the incidence of LV ECoG in the fetus. Twenty-one pregnant sheep were surgically prepared for chronic study of blood gases, ECoG activity, eye movements and FBM. After 3 days of recovery, ewes received a 70-mg bolus i.v. infusion of FX or sterile water followed by continuous infusion at a rate of 0.036 mg/min for 8 days. The incidence of low-voltage (LV) ECoG decreased from 54+/-4% on the preinfusion day to 45+/-5% on infusion day 1 in the FX group and remained decreased throughout the infusion period. In addition, the incidence of both eye movements and FBM was decreased on infusion day 1 compared to preinfusion day in the FX group. HV ECoG increased from 39+/-3% on preinfusion day to 68+/-14% on FX infusion day 1 and remained elevated throughout the infusion period. These data show that maternal FX administration alters fetal behavioural state.

Animals↗
PubMed2001

Mechanisms of bradykinin-mediated Ca(2+) signalling in canine cultured corneal epithelial cells.

Experiments were designed to differentiate the mechanisms of bradykinin receptors mediating the changes in intracellular Ca(2+) concentration ([Ca(2+)](i)) in canine cultured corneal epithelial cells (CECs). Bradykinin and Lys-bradykinin caused an initial transient peak of [Ca(2+)](i) in a concentration-dependent manner, with half-maximal stimulation (pEC(50)) obtained at 6.9 and 7.1, respectively. Pretreatment of CECs with pertussis toxin (PTX) or cholera toxin (CTX) for 24 h did not affect the bradykinin-induced [Ca(2+)](i) changes. Application of Ca(2+) channel blockers, diltiazem and Ni(2+), inhibited the bradykinin-induced Ca(2+) mobilization, indicating that Ca(2+) influx was required for the bradykinin-induced responses. Addition of thapsigargin (TG), which is known to deplete intracellular Ca(2+) stores, transiently increased [Ca(2+)](i) in Ca(2+)-free buffer, and subsequently induced Ca(2+) influx when Ca(2+) was readded to this buffer. Pretreatment of CECs with TG completely abolished bradykinin-induced initial transient [Ca(2+)](i), but had slight effect on bradykinin-induced Ca(2+) influx. Pretreatment of CECs with 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole (SKF96365) and 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122) inhibited the bradykinin-induced Ca(2+) release and Ca(2+) influx, consistent with the inhibition of receptor-gated Ca(2+) channels and phospholipase C (PLC) in CECs, respectively. These results demonstrate that bradykinin directly stimulates B(2) receptors and subsequently Ca(2+) mobilization via a PTX-insensitive G protein in canine CECs. These results suggest that bradykinin-induced Ca(2+) influx into the cells is not due to depletion of these Ca(2+) stores, as prior depletion of these pools by TG has no effect on the bradykinin-induced Ca(2+) influx that is dependent on extracellular Ca(2+) in CECs.

Animals↗
PubMed2001

A preliminary study on comparison and fusion of metabolic images of PET with anatomic images of CT and MRI.

OBJECTIVE: To compare and match metabolic images of PET with anatomic images of CT and MRI. METHODS: The CT or MRI images of the patients were obtained through a photo scanner, andthen transferred to the remote workstation of PET scanner with a floppy disk. A fusion method was developed to match the 2-dimensional CT or MRI slices with the correlative slices of 3-dimensional volume PET images. RESULTS: Twenty-nine metabolically changed foci were accurately localized in 21 epilepsy patients' MRI images, while MRI alone had only 6 true positive findings. In 53 cancer or suspicious cancer patients, 53 positive lesions detected by PET were compared and matched with the corresponding lesions in CT or MRI images, in which 10 lesions were missed. On the other hand, 23 lesions detected from the patients' CT or MRI images were negative or with low uptake in the PET images, and they were finally proved as benign. CONCLUSIONS: Comparing and matching metabolic images with anatomic images helped obtain a full understanding about the lesion and its peripheral structures. The fusion method was simple, practical and useful for localizing metabolically changed lesions.

Carcinoma, Squamous Cell↗
PubMed1999

Morphological, immunohistochemical and quantitative studies of murine brain mast cells after mating.

The mast cell is one of the immune cells, and can be triggered behaviorally to increase in the CNS of the sexually active dove. In the present study, we used ICR mice to investigate the number of brain mast cells in mated (one male with three female mice), non-mated (housed with female mice, but no mating) and control (four male mice housed together in one cage) male mice. We found that at least 40% of mated male mice had significant more mast cells than the maximum value seen in the controls, and that a significant correlation existed between the distribution index of mast cells and the postcoitum date. These mast cells were especially numerous in the thalamus and velum interpositum (VIP). Morphological observations showed that the increased mast cells were ultrastructurally similar to those in the controls, and displayed gonadotropin-releasing hormone (GnRH)-like immunoreactivity. Based on the facts that the number of brain mast cells in the male mice increased significantly after mating and that the change in the distribution of mast cells in the VIP and the thalamic parenchyma correlated well with time postcoitum, we speculate that, after mating, mast cells may migrate from the VIP to the thalamic parenchyma along the vascular tree of the brain. These results strongly suggest that mast cells are involved in the interaction among the immune, endocrine, and nervous systems in the mated male mouse brain.

Animals↗
PubMed1997

Automated analysis of protein NMR assignments using methods from artificial intelligence.

An expert system for determining resonance assignments from NMR spectra of proteins is described. Given the amino acid sequence, a two-dimensional 15N-1H heteronuclear correlation spectrum and seven to eight three-dimensional triple-resonance NMR spectra for seven proteins, AUTOASSIGN obtained an average of 98% of sequence-specific spin-system assignments with an error rate of less than 0.5%. Execution times on a Sparc 10 workstation varied from 16 seconds for smaller proteins with simple spectra to one to nine minutes for medium size proteins exhibiting numerous extra spin systems attributed to conformational isomerization. AUTOASSIGN combines symbolic constraint satisfaction methods with a domain-specific knowledge base to exploit the logical structure of the sequential assignment problem, the specific features of the various NMR experiments, and the expected chemical shift frequencies of different amino acids. The current implementation specializes in the analysis of data derived from the most sensitive of the currently available triple-resonance experiments. Potential extensions of the system for analysis of additional types of protein NMR data are also discussed.

Automation↗
PubMed1995

Separation of multiple forms of acidic glutathione S-transferase isozymes in a susceptible and a resistant strain of house fly, Musca domestica (L.).

The acidic glutathione S-transferases from a CSMA (susceptible) strain and a Cornell-R (resistant) strain of houseflies were purified and separated utilizing affinity chromatography followed by chromatofocusing. Nine fractions were isolated from each house fly strain. Fraction 1 had the highest 1-chloro-2,4-dinitrobenzene vs. 1,2-dichloro-4-nitrobenzene ratio (CDNB/DCNB ratio) in both strains and the ratio of all the other fractions tended to decrease as the isoelectrical points decreased except for fractions 4 and 9. Most fractions from the CSMA strain had higher CDNB conjugation activities than the fractions from the Cornell-R strain, but all the fractions from the CSMA strain had lower DCNB conjugation activities than fractions from the Cornell-R strain. Steady-state kinetics of all the fractions were examined. The Km values obtained from both strains ranged from 0.36 to 1.12 mM, while the Vmax value ranged from 3.0 to 32.6 mumol/min/mg. In the 100,000 g supernatant, the CDNB specific activities in the CSMA strain was about 1/3 of the activity in the Cornell-R strain but it was about 1.5-fold following affinity chromatography. The specific activity for DCNB measured in the CSMA strain was only 1/5 of the activities of the Cornell-R strain in the 100,000 g supernatant, but was about the same after affinity chromatography. The difference was due to the selectivity of the affinity column used in the current study.

Animals↗
PubMed1994

Immunological comparison of cytosolic glutathione S-transferases between rat and two strains of houseflies.

Five different antisera, which include three antisera raised against rat liver glutathione S-transferases (GST), one antiserum raised against human pi GST, and one antiserum raised against housefly GST1, were used to examine their cross-reactivity with different classes of GST subunits isolated from rat liver and the housefly. Two classes of rat liver GSTs, alpha and mu, were isolated from rat liver and two classes of housefly GSTs, GST1 and GST2, were isolated from both CSMA and Cornell-R strains. Antiserum against GST 3-3 was the most reactive antiserum and reacted not only with the mu class of GSTs but also with the GST1 class from both CSMA and Cornell-R strains. Antiserum against human pi GST and antiserum against housefly GST1 had weak immunological reactivity toward the GST1 class from both strains of housefly. Antiserum against GST 4-4 and antiserum against GST 1-1 had no immunological reactivity toward any class of GSTs from housefly. None of the five antisera had any immunological cross-reactivity toward subunit 2 of the alpha class of rat GST and the GST2 class of housefly GSTs from both strains.

Animals↗
PubMed1982

A study of the ecology of the house dust mite in dwelling houses.

The habitat of dust mites in dwelling houses in Japan was studied to determine the relation between mites in dust and mite allergy. Dust mites increased in the summer and decreased in the winter. Mite propagation was influenced by the temperature and relative humidity. Mites were found in higher concentrations in dust from concrete houses than that from wooden houses. Carpet dust contained numerous mites and tatami, sofas and bed mattresses were also habitats of mites. Mites existed universally in all samples of dust examined. Sensitization to mite allergen depends mainly on the atopic diathesis of patients and not on the mite count.

Animals↗
PubMed1982

Assessment of postoperative hearing in 528 middle ear and mastoid surgery cases in Tokai University Hospital.

The postoperative hearing results in cases of tympanoplasty, radical mastoidectomy, modified radical mastoidectomy and tympanoplasty combined with modified radical mastoidectomy on 528 ears, performed in the Tokai University Hospital between 1975 and 1980 were assessed. The assessment was based on pure-tone audiograms taken 3 months to 5 years after the operation. Out of 528 cases 70.5% gained better postoperative hearing, 6% showed no change of hearing and 23.5% showed deterioration of hearing. Auditory success of those who attained social hearing, air-bone gap closure to within 20dB or gained hearing of 20 dB or more was 53.4%. The results in cholesteatoma cases were poorer than those of non-cholesteatoma cases. In 44% of the cases, ossiculoplasty was performed, and the most successful ossiculoplasty results were obtained when the malleus was repositioned to the head of the stapes. Fairly good results were achieved when an artificial prosthesis, such as a Teflon-piston, Gelfoam-wire or platinum-piston, was used. The least successful results were found when the incus was transpositioned. In the non-ossiculoplasty group, type I tympanoplasty produced 59.5% auditory success whereas 37.3% auditory success was achieved in radical mastoidectomy. Better auditory success rates were obtained when the bony bridge was preserved than when it was removed. The results were identical in cases where the mastoid cavity was obliterated or when it was kept open. A new technique, "scutumplasty", was used for reconstructing the scutum. Revision surgery was required in only 3.4% of the cases.

Hearing↗