Search PubMed⌕ Search

Biomedical subjects

C P Chen

Publications and source records attributed to C P Chen.

At least 19 recordsLinked to original sources
PubMed2001

Psychosis of Alzheimer's disease is associated with elevated muscarinic M2 binding in the cortex.

OBJECTIVES: Results from recent drug trials suggest a role for the cholinergic system in the manifestation of neuropsychiatric symptoms in AD. To date, the status of muscarinic acetylcholine receptor subtypes in AD in relation to accompanying behavioral disturbances is unknown. This study aimed to measure alterations of muscarinic M(1) and M(2) receptor binding in the frontal and temporal cortex of AD and to correlate the neurochemical findings with clinical features. METHODS: The cognitive and behavioral features of 26 patients with AD were assessed prospectively using standardized tests. Together with 14 matched controls, the status of muscarinic M(1) and M(2) receptors in the postmortem frontal and temporal cortex of these patients were measured by radioligand binding assays and were correlated with clinical data. RESULTS: Compared with controls, M(2) receptor density was reduced only in the frontal cortex of AD, whereas M(1) was unaffected. Within the AD group, the neurochemical variables were not affected by demographic factors, disease severity, or cognition. Instead, M(2) receptor density was increased in the frontal and temporal cortex of patients with AD with psychotic symptoms compared with those without these symptoms. CONCLUSIONS: This study suggests a role for M(2) receptors in the psychosis of AD and may provide the rationale for treatment of behaviorally perturbed patients with AD with cholinomimetics and M(2) antagonists.

Aged↗
PubMed2001

New mechanism of x-ray radiation from a relativistic charged particle in a dielectric random medium.

Based on the diffusional scattering of pseudophotons, we propose a new mechanism of x-ray radiation from a relativistic charged particle moving in a system consisting of microspheres distributed randomly in a dielectric material. The mechanism leads to a stronger dependence of radiation intensity on the particle energy, gamma = E/mc(2), than that predicted by the transition radiation, and explains recent experimental data from a detector which contains randomly distributed superconducting granules.

Journal Article↗
PubMed2001

Prenatal diagnosis of mosaic ring chromosome 13 with anencephaly.

We report on the prenatal diagnosis, genetic analysis and clinical manifestations of a second-trimester fetus with mosaic ring chromosome 13 and anencephaly. A 35-year-old, gravida 3, para 2 woman was referred for genetic counselling at 23 weeks' gestation because of an elevated maternal serum alpha-fetoprotein level of 2.386 multiples of the median. Prenatal ultrasonography showed intrauterine growth retardation and anencephaly. Amniocentesis revealed a karyotype of de novo mos 46,xx,r(13)(p11q32)/45,xx,-r(13) [corrected] (77%/23%). Molecular genetic analysis by quantitative fluorescent polymerase chain reaction (PCR) with small tandem repeat markers specific for chromosome 13 rapidly confirmed the maternal origin of the aberrant chromosome and determined the breakpoint at 13q32 between D13S225 (present) and D13S147 (absent). Our present finding indicates that anencephaly can be due to mosaic r(13) with a terminal deletion of 13q32-13q34 and an additional secondary rearrangement of loss of r(13). We propose that cytogenetic analysis is beneficial and warranted in pregnancies with fetal neural tube defects.

Adult↗
PubMed2001

Prenatal diagnosis and genetic analysis of type I and type II thanatophoric dysplasia.

Thanatophoric dysplasia (TD) is one of the most common neonatal lethal skeletal dysplasias. Prenatal sonographic and molecular genetic diagnoses of three cases of TD type I (TD1) and one case of TD type II (TD2) are presented here. Two fetuses of TD1 were characterized by polyhydramnios, macrocephaly, short limbs, a narrow thoracic cage and curved short femora, but without a cloverleaf skull at 27 and 31 weeks' gestation, respectively. The third fetus with TD1 was, however, not associated with macrocephaly, polyhydramnios, chest narrowing and severe femoral bowing on prenatal ultrasound at 18 weeks' gestation. The TD2 fetus was characterized by polyhydramnios, short limbs, a narrow thoracic cage, straight short femora, hydrocephalus and a cloverleaf skull at 24 weeks' gestation. Three-dimensional ultrasound was able to enhance the visualization of thickened, redundant skin folds and craniofacial and limb deformities associated with TD. Molecular analysis of the fibroblast growth factor receptor 3 (FGFR3) gene by restriction enzyme digestion analysis and direct sequencing using cultured amniotic fluid cells or cord blood cells revealed a missense mutation of 742C-->T (Arg248Cys) in all cases with TD1 and a missense mutation of 1948A-->G (Lys650Glu) in the case with TD2. The present report shows that adjunctive applications of molecular genetic analysis of the FGFR3 gene and three-dimensional ultrasound are useful for prenatal diagnosis of TD.

Adult↗
PubMed2001

Gender difference in DNA adduct levels among nonsmoking lung cancer patients.

Lung cancer is the leading cause of cancer mortality in Taiwanese women. Cigarette smoking cannot explain the high lung cancer mortality in this population because less than 10% of women in Taiwan are smokers. Therefore, environmental factors other than smoking may play an important role in lung cancer development in female nonsmokers. The purpose of this study was to elucidate the role of environmental carcinogen exposure in lung cancer development in Taiwanese female nonsmokers, based on DNA adduct formation. We collected nontumorous lung tissues resected from 62 nonsmoking lung cancer patients and 20 noncancer controls to investigate whether differences in susceptibility to DNA adduct formation exist between men and women. (32)P-postlabeling and ELISA (enzyme-linked immunosorbent assay) with polyclonal antibody against BPDE (7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene)-DNA adduct were used to evaluate DNA adduct levels in lung tissues of study subjects. Our data showed that the DNA adduct levels of lung cancer patients determined by both assays were significantly higher than those of noncancer controls (P = 0.0001 for (32)P-postlabeling; P = 0.01 for ELISA). Moreover, DNA adduct levels in females were markedly greater than those in males (P = 0.014 for (32)P-postlabeling; P = 0.001 for ELISA). The difference in DNA adduct levels could not be explained by genetic polymorphisms of cytochrome P-4501A1 (CYP1A1) or glutathione S-transferase (GSTM1), as determined by polymerase chain reaction and restriction fragment length polymorphism. These results demonstrate that lung cancer patients have a higher susceptibility to DNA damage than that of noncancer controls. In addition, differences in susceptibility to DNA damage derived from environmental carcinogen exposure were observed between male and female nonsmokers. In conclusion, high susceptibility to DNA damage in females may partially explain the high mortality rate of lung cancer in nonsmoking Taiwanese women.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed2001

Prenatal diagnosis of de novo distal 11q deletion associated with sonographic findings of unilateral duplex renal system, pyelectasis and orofacial clefts.

In utero diagnosis of de novo distal 11q deletion associated with renal and orofacial malformations has not been previously described. We present a 35-year-old pregnant woman with prenatal sonographic findings of a unilateral duplex renal system, pyelectasis and orofacial clefts at 20 weeks' gestation. Both genetic amniocentesis and postnatal cytogenetic analysis revealed de novo 46,XX,del(11)(q23). After birth, the fetus manifested a dysmorphic phenotype correlated with del(11q) syndrome. Genetic marker analysis showed a paternally derived distal deletion of chromosome 11q and a breakpoint centromeric to D11S1341. The present case represents the earliest prenatal diagnosis of a duplex renal system, pyelectasis and an additional feature of orofacial clefts associated with distal 11q deletion. Prenatal sonographic detection of a duplex renal system, pyelectasis and orofacial clefts should warrant a careful assessment of fetal anatomy and prompt cytogenetic analysis looking for chromosomal aberrations.

Abortion, Induced↗
PubMed2001

Prenatal diagnosis of partial monosomy 18p(18p11.2-->pter) and trisomy 21q(21q22.3-->qter) with alobar holoprosencephaly and premaxillary agenesis.

A prenatal diagnosis of partial monosomy 18p(18p11.2-->pter) and trisomy 21q(21q22.3-->qter) in a fetus with alobar holoprosencephaly (HPE) and premaxillary agenesis (PMA) but without the classical Down syndrome phenotype is reported. A 27-year-old primigravida woman was referred for genetic counselling at 21 weeks' gestation due to sonographic findings of craniofacial abnormalities. Level II ultrasonograms manifested alobar HPE and median orofacial cleft. Cytogenetic analysis and fluorescence in situ hybridization (FISH) on cells obtained from amniocentesis revealed partial monosomy 18p and a cryptic duplication of 21q,46,XY,der(18)t(18;21)(p11.2;q22.3), resulting from a maternal t(18;21) reciprocal translocation. The breakpoints were ascertained by molecular genetic analysis. The pregnancy was terminated. Autopsy showed alobar HPE with PMA, pituitary dysplasia, clinodactyly and classical 18p deletion phenotype but without the presence of major typical phenotypic features of Down syndrome. The phenotype of this antenatally diagnosed case is compared with those observed in six previously reported cases with monosomy 18p due to 18;21 translocation. The present study is the first report of concomitant deletion of HPE critical region of chromosome 18p11.3 and cryptic duplication of a small segment of distal chromosome 21q22.3 outside Down syndrome critical region. The present study shows that cytogenetic analyses are important in detecting chromosomal aberrations in pregnancies with prenatally detected craniofacial abnormalities, and adjunctive molecular investigations are useful in elucidating the genetic pathogenesis of dysmorphism.

Adult↗
PubMed2001

Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis.

The antimicrobial activity of honokiol and magnolol, the main constituents of Magnolia officinalis was investigated. The antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (MIC) were determined for each compound using a twofold serial dilution assay. The results showed that honokiol and magnolol have a marked antimicrobial effect (MIC = 25 microg/mL) against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Micrococcus luteus and Bacillus subtilis, but did not show antimicrobial activity (MIC > or = 100 microg/mL) for Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa. Our results indicate that honokiol and magnolol, although less potent than tetracycline, show a significant antimicrobial activity for periodontal pathogens. Hence we suggest that honokiol and magnolol might have the potential to be an adjunct in the treatment of periodontitis.

Actinobacillus↗
PubMed2001

Multiple globules in a cystic ovarian teratoma.

OBJECTIVE: To describe the characteristic imaging findings of multiple globules and globules-fluid level in a cystic ovarian teratoma. DESIGN: Descriptive case study. SETTING: Mackay Memorial Hospital and National Yang-Ming University, Taipei, Taiwan, Republic of China. PATIENT(S): A 20-year-old woman with left abdominal discomfort and a palpable mass on the left side of the distended abdomen. INTERVENTION(S): Surgical removal of a 10-cm cystic ovarian teratoma that contained chocolate-like fluid and multiple spheroid mobile globules consisting of yellowish sebaceous debris and fine hair shafts. MAIN OUTCOME MEASURE(S): Plain abdominal radiography, ultrasonography, and computed tomography (CT). RESULT(S): Plain abdominal radiography revealed no calcification in the mass. The first sonographic examination showed no movement by positional change of multiple rounded echogenic masses ranging from 0.5 cm to 2 cm in diameter, but the second CT examination done after the patient had spent some time lying down showed that the rounded masses arrayed in the upper portion of the cyst and displayed the characteristic level of globules-fluid. Thus, the differential diagnosis was multiple mobile globules in a cystic ovarian tumor. CONCLUSION(S): This case indicates that fatty masses need time to float upward in the fluid matrix of a cystic ovarian teratoma. This delayed effect should be considered when an ovarian cyst with multiple rounded echogenic masses is diagnosed by ultrasonography, CT, or magnetic resonance imaging.

Abdominal Pain↗
PubMed2001

Renal biopsy in pregnancies complicated by undetermined renal disease.

BACKGROUND: The aim of this retrospective study was to verify the role of renal biopsy in pregnancies complicated by renal dysfunction. METHODS: A series of 15 percutaneous renal biopsies performed in 15 pregnant women with renal disease presenting during pregnancy over the past 10 years (1990-1999) were reviewed. RESULTS: All the patients underwent renal biopsy before 30 weeks of gestation. The indications for renal biopsy were renal dysfunction of unknown cause or symptomatic nephrotic syndrome (NS). Patients with toxemia were excluded. Eight women had lupus nephritis, including five with diffuse crescenteric changes and three with a mesangial proliferative pattern. Three had chronic glomerulonephritis (CGN), two had mesangial proliferative glomerulonephritis and one each had diabetic nephrosclerosis and endocapillary proliferative glomerulonephritis. There were no significant complications except in one patient who experienced gross hematuria. Early induction of labor was recommended for the four patients with diabetic nephrosclerosis or CGM. The other 11 patients received intravenous pulse methylprednisolone or high dose oral prednisolone therapy. The responses to steroid therapy in these 11 patients were as follows: five achieved complete remission of NS, three achieved incomplete remission, and three achieved partial remission. After 2 years' follow-up, seven mothers achieved complete remission, three had died, three developed chronic renal failure (CRF), and two progressed to end stage renal failure (ESRF) requiring chronic hemodialysis. Fourteen of the 15 pregnancies resulted in live births and the other child was stillborn. CONCLUSIONS: Renal biopsy performed during pregnancy is not contraindicated. The results of histopathological studies are extremely useful in counseling regarding continuation or termination of pregnancy, potential maternal and fetal outcome, and recommending specific therapeutic modalities.

Adult↗