Biomedical subjects

C I Chen

Publications and source records attributed to C I Chen.

24 records · Page 2Linked to original sources

PubMed1997

Metacercariae in fishes of Sun Moon lake which is an endemic area for Clonorchis sinensis in Taiwan.

The Sun Moon lake in Central Taiwan is a known endemic area for clonorchiasis. Of the 45 fresh water fish, Hemiculter leucisculus, from the lake that were examined by artificial gastric juice digestion in October 1995, all were found to harbor metacercariae in their muscle. The number of metacercariae isolated from each fish ranged from 2 to 2,185, with an average of 254. A total of 11,443 metacercariae was collected from the 45 fish. Of the 4,223 metacercaria that were examined under light microscope, 4,064 (96.23%) were found to belong to Haplorchis taichui, 90(2.13%) to H. pumilio, 2(0.05%) to C. sinensis and 67 (1.59%) to unknown species due to the metacercariae being not yet developed or immature. The 2 C. sinensis metacercariae were obtained from 2 out of 45 fish examined. Our results contrast with reports of a decade ago which stated that all the fish of the Sun Moon lake examined were positive for C. sinensis. Possible reasons for the decrease of C. sinensis metacercariae are the disappearance of pig farms around the lake, increased awareness of the trematode by the lakeside inhabitants and probably the exclusive use of mammals as its definitive host by C. sinensis. In contrast, besides mammals, Haplorchis spp also use birds as their definitive hosts.

Animals↗

PubMed1996

Coronary microvascular dysfunction is associated with ischemic-like electrocardiogram during exercise in patients with anginal chest pain and normal coronary angiograms.

To determine the possible mechanism of the ischemic-like electrocardiogram (ECG) during exercise in the presence of anginal chest pain and normal coronary angiograms, both a treadmill exercise test (TET) and coronary hemodynamic study were prospectively performed in 33 consecutive patients (18 females and 15 males, aged 48 +/- 10 years) with angina of unknown cause. Although baseline characteristics and coronary hemodynamics were similar between patients with (TET+, n = 17) and those without (TET-, n = 16) ischemic-like ECG during TET, effort angina was more frequently seen in the former group (p < 0.01). Compared to TET- patients, TET+ patients had a significantly lower maximum great cardiac vein flow (GCVF, 108.8 +/- 47.0 vs 146.4 +/- 23.4 ml/min, p = 0.007), higher minimum coronary vascular resistance (0.94 +/- 0.41 vs 0.61 +/- 0.09 mmHg/ml/min., p = 0.003), and lower corrected GCVF (GCVF/rate-pressure product, 0.0087 +/- 0.0036 vs 0.0125 +/- 0.0019, p = 0.001) after dipyridamole infusion (0.56 mg/kg for 4 min). Though coronary flow reserve was significantly lower in TET+ than in TET- patients (2.26 +/- 0.59 vs 3.08 +/- 0.48, p = 0.0001), myocardial oxygen consumption and myocardial efficiency (rate-pressure product/myocardial oxygen consumption) were still similar between these two groups after dipyridamole infusion. Thus, coronary microvascular dysfunction rather than altered cardiac metabolism could contribute to effort angina and ischemic-like ECG during exercise in patients with anginal chest pain and normal coronary angiograms.

Adult↗

PubMed1995

Peroxisomal activation of long- and very long-chain fatty acids in the yeast Pichia pastoris.

In mammals, beta-oxidation of very long-chain fatty acids (VLCFA) takes place in peroxisomes. This process is impaired in X-linked adrenoleukodystrophy (XALD) patients as a result of decreased activity of peroxisomal very long-chain acyl-CoA synthetase (VLCS). We investigated VLCFA and long chain fatty acid (LCFA) activation in the yeast Pichia pastoris. Both VLCFA and LCFA were activated to their CoA derivatives in an organelle fraction. When organelles were fractionated on a sucrose gradient, VLCS activity co-localized with peroxisomes while long chain acyl-CoA synthetase activity associated primarily with mitochondria. Consistent with these findings, only VLCS activity was reduced in organelle fractions from peroxisome assembly (pas) mutants. Furthermore, no VLCS activity was detected in pas mutants at the density of normal peroxisomes. Thus, we conclude that VLCS is a peroxisomal enzyme in P. pastoris and this organism may serve as an excellent model system to investigate the molecular basis of XALD.

Adrenoleukodystrophy↗

PubMed1994

Comparison of respiratory activity and culturability during monochloramine disinfection of binary population biofilms.

Biofilm bacteria challenged with monochloramine retained significant respiratory activity, even though they could not be cultured on agar plates. Microbial colony counts on agar media declined by approximately 99.9% after 1 h of disinfection, whereas the number of bacteria stained by a fluorescent redox dye experienced a 93% reduction. Integrated measures of biofilm respiratory activity, including net oxygen and glucose utilization rates, showed only a 10 to 15% reduction. In this biofilm system, measures of microbial respiratory activity and culturability yielded widely differing estimates of biocide efficacy.

Chloramines↗

PubMed1989

Cytoplasmic CD3+ surface CD8+ lymphocytes develop as a thymus-independent lineage in chick-quail chimeras.

We have analyzed the embryonic development of a population of lymphoid cells that express a CD3 antigenic determinant in the cytoplasm but not on the cell surface. Since these cells lack T cell receptor (TcR) molecules, we have provisionally named them TCRO cells. Their development, expansion and distribution was investigated following transplantation of splenic and bursal fragments from chicken embryos into quail embryos. Since quail cells are not recognized by our panel of monoclonal antibodies against chicken TcR1, TcR2, TcR3, CD3, CD4 and CD8 molecules, these antibodies provided reliable markers for donor chick lymphocytes in the tissues of the quail recipients. Transplanted spleen and bursa both generated CD3+ cells, the number of which increased as a function of age. Notably, approximately half of these CD3+ cells expressed surface CD8, but none acquired TcR1 (gamma/delta), TcR2 (alpha/beta) or TcR3 expression. Since TCRO cells normally appear first in the spleen of 8-day chick embryos (E8), their generation in E6 splenic transplants indicated an extrathymic origin. The TCRO cells of chick splenic origin migrated to the spleen, bursa and thymus of the quail recipients. In six of seven chimeras acquiring CT3+ cells in the recipient thymus, these cells were restricted to the medulla and displayed the typical TCRO phenotype: CD3+CD8+TcR1-TcR2-TcR3-. These intrathymic TCRO cells also lacked the CT1 thymocyte antigen. We conclude that the TCRO cells represent a thymus-independent lineage of lymphoid cells that can migrate into a receptive thymus by rarely, if ever, differentiate into conventional T cells.

Animals↗

PubMed1987

Prevalence and significance of group B Streptococcus in a large obstetric population.

Between Jan. 1 and Dec. 31, 1985, vaginal swabs were obtained for culture for group B beta-hemolytic Streptococcus (GBS) from 3078 women admitted for labour and delivery to Regina General Hospital. Seventy-one women had positive results; thus, the colonization rate was only 2.3%. The charts of the 71 women and their 73 babies were analysed. Of the 58 babies from whom swabs were obtained, 20 had GBS at one or more sites; the transmission rate was therefore 34%. Early-onset GBS disease developed in one infant. Two infants died within the first month; however, death was not directly attributable to GBS. Higher rates of preterm delivery and of low birth weight were noted among the babies of the colonized women than among the babies of all women admitted for labour and delivery in 1985. Given the low rate of GBS disease in our centre, we suggest that emphasis be placed on GBS as a possible source of obstetric complications such as preterm labour.

Adolescent↗