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Biomedical subjects

C C Lee

Publications and source records attributed to C C Lee.

At least 235 records · Page 13Linked to original sources
PubMed1998

Isochromosome 18q in a fetus with congenital megacystis, intra-uterine growth retardation and cloacal dysgenesis sequence.

We present the first report of a female fetus with concomitant isochromosome 18q [i(18q)] and cloacal dysgenesis sequence. Prenatal sonographic examination at 15 weeks' gestation showed intra-uterine growth retardation, a normal brain, a normal spine, congenital megacystis and oligohydramnios. The pregnancy was terminated. The abortus displayed dysmorphic features of a high forehead, hypertelorism, a prominent nose with a bulbous tip, median cleft lip and palate, micrognathia, low-set ears, a short neck, a joint contracture at the wrist, prominent heels and pseudo-hermaphroditism. Necropsy confirmed an imperforate anus, megacystis, a phallic structure and cloacal dysgenesis sequence. Postnatal chromosomal investigation proved a pure de novo i(18q). Molecular genetic analysis by polymorphic microsatellite markers confirmed the maternal origin of the aberrant chromosome. The coexistence of cloacal dysgenesis sequence and i(18q) in this case shows a correlation between the disturbance of the caudal developmental field and the chromosomal abnormality with monosomy 18p and trisomy 18q. Our presentation also demonstrates the importance of perinatal cytogenetic analysis in malformed fetuses in order to uncover underlying genetic disorders.

Abnormalities, Multiple↗
PubMed1997

A differential response of two putative mammalian circadian regulators, mper1 and mper2, to light.

A mouse gene, mper1, having all the properties expected of a circadian clock gene, was reported recently. This gene is expressed in a circadian pattern in the suprachiasmatic nucleus (SCN). mper1 maintains this pattern of circadian expression in constant darkness and can be entrained to a new light/dark cycle. Here we report the isolation of a second mammalian gene, mper2, which also has these properties and greater homology to Drosophila period. Expression of mper1 and mper2 is overlapping but asynchronous by 4 hr. mper1, unlike period and mper2, is expressed rapidly after exposure to light at CT22. It appears that mper1 is the pacemaker component which responds to light and thus mediates photic entrainment.

Amino Acid Sequence↗
PubMed1997

Antirhino/enteroviral vinylacetylene benzimidazoles: a study of their activity and oral plasma levels in mice.

In an effort to find an orally bioavailable antiviral for the treatment of rhino/enteroviral infections, a series of vinylacetylene benzimidazoles (11a-o, 12, and 18a) was made. Initial studies of this class of antivirals showed that fluorine substitution on the left-hand phenyl ring in combination with the vinylacetylene moiety gave the requisite mix of physical properties to achieve good in vitro antiviral activity as well as respectable oral bioavailability in rhesus monkeys. To ascertain the generality of this finding and to broaden the scope of the structure-activity relationship (SAR), the present study concentrated on fluoro substitution of this class of molecules. The initial antiviral activity for each analogue was measured using human rhinovirus 14 (HRV-14). This served as an indicator of general antiviral activity for SAR purposes. Subsequently, the spectrum of antirhino/enteroviral activity of the more interesting analogues was evaluated through testing against a panel of seven additional rhino/enteroviruses. Broad-spectrum activity was present and consistent for all analogues tested, and it tracked closely with the antiviral activity observed against HRV-14. A simple screening protocol for oral bioavailability was established whereby compounds were administered orally to mice and plasma levels were measured. This procedure facilitated the evaluation of numerous analogues in a rapid manner. The Cmax was used as a measure of oral bioavailability to allow relative ranking of compounds. In general, fluorine substitution directly on the left-hand aromatic ring does give good oral blood levels. However, fluorine incorporation at other positions in the molecule was not as effective at maintaining either the activity or the oral plasma levels. The constructive combination of activity and oral plasma levels was maximized in three derivatives: 11a,e,g.

Administration, Oral↗
PubMed1997

Cyclin D1 overexpression in rat two-stage bladder carcinogenesis and its relationship with oncogenes, tumor suppressor genes, and cell proliferation.

Overexpression of cyclin D1 has been implicated in the malignant transformation of a variety of human cancers, including urinary bladder carcinomas. However, few reports have addressed the significance of cyclin D1 overexpression in chemical carcinogenesis in rodents. In the present study, we evaluated the oncogenic potential of cyclin D1 in experimental rat urinary bladder carcinogenesis and its relationships to the oncogenes cyclin E, K-ras, and H-ras as well as tumor suppressor genes p53 and p21WAF1/Cip1. In addition, proliferation status of preneoplastic lesions and tumors was assessed by proliferating cell nuclear antigen immunohistochemistry. Fisher 344 rats were initiated with 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in the drinking water for 4 weeks and then administered 5% sodium L-ascorbate in diet. Animals were sacrificed at weeks 4, 8, 12, 18, and 24. Preneoplastic lesions such as papillary or nodular hyperplasia and neoplastic lesions of the urinary bladder were observed during carcinogenesis. By immunohistochemical examination, overexpression of cyclin D1 protein was observed in 17% of papillary or nodular hyperplasias, 66% of papillomas, and 69% of transitional cell carcinomas, whereas nuclear accumulation of p53 was observed in none of the preneoplastic lesions and in fewer than 2% of transitional cell carcinomas. Overexpression of cyclin D1 in preneoplastic lesions and tumors was not dependent on the size of the tumors or their proliferation status. Quantitation of mRNA in tumors by multiplex reverse transcription-PCR showed that average mRNA expression of cyclin D1 and cyclin E was increased, whereas average p21WAF1/Cip1 mRNA expression was decreased. More than 2-fold overexpression of cyclin D1 mRNA was observed in 50 and 60% of tumors at weeks 18 and 24, respectively. Localization of cyclin D1 mRNA expression was demonstrated by in situ hybridization, and the results were comparable to immunohistochemistry findings. None of the 25 tumors we examined by PCR-single-strand conformational polymorphism analysis harbored p53 mutations, H-ras mutations, or K-ras mutations. Thus, during the promotion phase of two-stage bladder carcinogenesis, overexpression of cyclin D1 in tumor cells may provide yet another mechanism by which tumors can gain a growth advantage. In contrast, tumors with mutated p53 may not have a growth advantage. Our results suggest that overexpression of cyclin D1 plays a critical role during urinary bladder carcinogenesis.

Animals↗
PubMed1997

The effects of the cholesterol ester transfer protein gene and environmental factors on the plasma high density lipoprotein cholesterol levels in the Korean population.

The cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that transfers neutral lipids between plasma lipoproteins. The distribution of variations in the CETP gene and their influences on lipid levels were investigated among random members of the Korean population (n = 270) whose profiles of environmental factors were known. The frequencies of the major allele at BamHI, EcoNI, TaqIA, TaqIB, New HinfI RFLPs, and the D442G mutation were 0.77, 0.55, 0.84, 0.62, 0.81, and 0.94, in serial order. The significant associations of the BamHI RFLP and the D442G mutation with the plasma high density lipoprotein (HDL) cholesterol levels were observed in this population. Subjects with genotype B2B2 of the BamHI RFLP had significantly lower HDL cholesterol levels than the mean of total subjects. Subjects with D442G mutant allele had a significantly higher HDL cholesterol levels only in males. Analysis of the covariance model (ANOCOVA) showed that allelic variations in the BamHI RFLP and the D442G mutation sites accounted independently for 4.0 and 5.9% of the total inter-individual variation in plasma HDL cholesterol in males (F = 2.29, p = 0.10; F = 3.4, p = 0.03). The effect of the CETP genotype was very high (about 10%), compared to the total effects of sex, body mass index, age, and smoking habit (20%). In conclusion, the genetic variation of the CETP gene is related to the regulation of plasma HDL cholesterol levels and the extent of the effect seems to be different between male and female in the Korean population.

Adult↗
PubMed1997

RIGUI, a putative mammalian ortholog of the Drosophila period gene.

The molecular components of mammalian circadian clocks are elusive. We have isolated a human gene termed RIGUI that encodes a bHLH/PAS protein 44% homologous to Drosophila period. The highly conserved mouse homolog (m-rigui) is expressed in a circadian pattern in the suprachiasmatic nucleus (SCN), the master regulator of circadian clocks in mammals. Circadian expression in the SCN continues in constant darkness, and a shift in the light/dark cycle evokes a proportional shift of m-rigui expression in the SCN. m-rigui transcripts also appear in a periodic pattern in Purkinje neurons, pars tuberalis, and retina, but with a timing of oscillation different from that seen in the SCN. Sequence homology and circadian patterns of expression suggest that RIGUI is a mammalian ortholog of the Drosophila period gene, raising the possibility that a regulator of circadian clocks is conserved.

Adaptation, Ocular↗
PubMed1997

Epidermal growth factor and betacellulin mediate signal transduction through co-expressed ErbB2 and ErbB3 receptors.

Interleukin-3 (IL-3)-dependent murine 32D cells do not detectably express epidermal growth factor receptors (EGFRs) and do not proliferate in response to EGF, heregulin (HRG) or other known EGF-like ligands. Here, we report that EGF specifically binds to and can be crosslinked to 32D transfectants co-expressing ErbB2 and ErbB3 (32D.E2/E3), but not to transfectants expressing either ErbB2 or ErbB3 individually. [125I]EGF-crosslinked species detected in 32D. E2/E3 cells were displaced by HRG and betacellulin (BTC) but not by other EGF-like ligands that were analyzed. EGF, BTC and HRG also induced receptor tyrosine phosphorylation, activation of downstream signaling molecules and proliferation of 32D.E2/E3 cells. 32D transfectants were also generated which expressed an ErbB3-EGFR chimera alone (32D.E3-E1) or in combination with ErbB2 (32D. E2/E3-E1). While HRG stimulation of 32D.E3-E1 cells resulted in DNA synthesis and receptor phosphorylation, EGF and BTC were inactive. However, EGF and BTC were as effective as HRG in mediating signaling when ErbB2 was co-expressed with the chimera in the 32D.E2/E3-E1 transfectant. These results provide evidence that ErbB2/ErbB3 binding sites for EGF and BTC are formed by a previously undescribed mechanism that requires co-expression of two distinct receptors. Additional data utilizing MDA MB134 human breast carcinoma cells, which naturally express ErbB2 and ErbB3 in the absence of EGFRs, supported the results obtained employing 32D cells and suggest that EGF and BTC may contribute to the progression of carcinomas that co-express ErbB2 and ErbB3.

Animals↗
PubMed1997

Genetic variation of the apolipoprotein B gene in Korean patients with coronary artery disease.

In view of the clinical importance of apolipoprotein B (apo B) as a major risk factor for coronary artery disease (CAD), we investigated the two polymorphisms (signal peptide and XbaI) of the apo B gene in 235 Korean patients with CAD and in 216 normal controls. The insertion allele (INS) frequency of signal peptide polymorphism was significantly higher in cases than the controls (P<0.05). Signal peptide polymorphism was also associated with levels of plasma cholesterol, triglyceride and low density lipoprotein-cholesterol. However, XbaI polymorphism was not associated with plasma lipid levels. Therefore, our results suggest that signal peptide polymorphism of the apo B gene might be one of the factors in explaining an association in Korean CAD patients.

Adult↗
PubMed1997

Purification and characterization of the prothoracicotropic hormone of Drosophila melanogaster.

The prothoracicotropic hormone (PTTH) of Drosophila melanogaster is a modulator of ecdysteroid (molting hormone) synthesis and was isolated and characterized from extracts of whole larvae (approximately 4 x 10(5) larvae). The purification protocol included delipidation, salt-extraction, heat treatment, conventional column chromatography, and HPLC, and yielded about 50 microg of pure hormone. Biological activity was followed using a ring gland in vitro assay in which ecdysteroidogenesis by control ring glands as measured by radioimmunoassay was compared with ring gland incubations containing active fractions. The molecular weight of the purified PTTH was 45 kDa and N-terminal amino acid sequence analysis indicated that those analyzed sequences displayed no significant homology with known peptides or peptide hormones, including PTTH from the silkmoth, Bombyx mori. Western blot analysis indicated that the native form of Drosophila PTTH was a single 66-kDa polypeptide with N-linked carbohydrate chains and intrachain disulfide bonds. The purified 45-kDa peptide is the deglycosylated form, a result of glycosidase activity present during preparation of the PTTH extract. The deglycosylated form shows heterogeneity, presumably as a result of varying degrees of deglycosylation at the N terminus.

Animals↗
PubMed1997

Significance of cyclin D1 overexpression in transitional cell carcinomas of the urinary bladder and its correlation with histopathologic features.

BACKGROUND: Genetic alterations leading to neoplastic transformation of the urothelium are likely to involve the activation of oncogenes and loss of functional tumor suppressor genes. Cyclin D1 has been implicated as a putative protooncogene whereas mutations of the p53 gene occur frequently in invasive transitional cell carcinomas (TCCs) of the urinary bladder. In this study, cyclin D1 overexpression and nuclear accumulation of p53 were evaluated and the results correlated with histopathologic features. METHODS: TCCs of the urinary bladder from 161 surgical procedures were evaluated for cyclin D1 overexpression and nuclear accumulation of p53. Results were correlated with tumor grade, T classification, and papillary status. Topologic distributions of cyclin D1, p53, and proliferating cellular nuclear antigen (PCNA) were evaluated. Northern blot analysis was performed on selected specimens. RESULTS: Overexpression of cyclin D1 was observed in 47% (24 of 51) of Grade 1 TCCs and 20% (13 of 65) of Grade 2 TCCs but in no Grade 3 TCCs. Approximately 34% (14 of 41) of Ta classified TCCs and 21% (13 of 63) of T1 classified TCCs were immunoreactive for cyclin D1 whereas none of the TCCs beyond T1 was immunoreactive. Overexpression of cyclin D1 was observed only in papillary type TCCs. Results of Northern blot analysis for cyclin D1 were comparable to those of immunohistochemistry. CONCLUSIONS: The observed significant relation between cyclin D1 overexpression and tumor grade/T classification suggests that cyclin D1 may be a useful biologic marker for biopsied materials or urine cytology specimens. The prognostic significance of cyclin D1 overexpression in TCCs remains to be determined.

Adult↗
PubMed1997

Isolation of novel genes from the CMT1A duplication/HNPP deletion critical region in 17p11.2-p12.

Charcot-Marie-Tooth disease type 1A (CMT1A) is associated with a 1.5-Mb tandem DNA duplication in chromosome 17p11.2-p12, while hereditary neuropathy with liability to pressure palsies (HNPP) is associated with a 1.5-Mb deletion at this locus. The 1.5-Mb CMT1A monomer unit duplicated in CMT1A and deleted in HNPP is flanked by low-copy repeats termed CMT1A-REPs. Both diseases appear to be caused by an altered copy number of the peripheral myelin protein 22 gene (PMP22), which lies within the critical region. To identify additional genes rapidly, we used a cosmid contig of this region and reciprocal probing of arrayed chromosome 17-specific cosmid and cDNA libraries. Three cDNA clones were identified within the CMT1A duplication/HNPP deletion region and one just proximal to the critical region. The cDNA for human heme A:farnesyltransferase (COX10) mapped 10 kb centromeric to the distal CMT1A-REP. The other two cDNA clones from within the critical interval mapped to cosmid 126D1 at the mfd41 (D17S261) DNA marker, and their conceptual translation showed homology to 60S ribosomal protein L9 (RPL9) and chromosomal protein RMSA-1 (RMSA-1). A gene that is homologous to human peroxisome proliferator activated receptor alpha (hPPARA) was identified near the proximal CMT1A-REP.

Alkyl and Aryl Transferases↗
PubMed1997

Prenatal diagnosis of cephalothoracopagus janiceps monosymmetros.

We report a case of cephalothoracopagus janiceps monosymmetros that was diagnosed prenatally by ultrasound at 23 weeks' gestation. Obstetric ultrasound demonstrated conjoined female twins with a single fused cranial vault irregular in contour, duplicated cerebra, one face, two eyeballs, a fused thorax, two hearts, two thoracic spines, eight limbs, and polyhydramnios. The pregnancy was terminated and all the features described prenatally were observed at necropsy. The asymmetrical fused faces consisted of a ventral humanoid face with micrognathia, microphthalmia, low-set ears, a normal nose, and an opposite reduced face with partial facial features of a central narrowed fissure and paired synotic ears. The conjoined twins had fused umbilical cords, omphalocoele, and a single oesophagus, stomach, and duodenum, but duplicated pancreases, spleens, and central nervous, cardiopulmonary, hepatic, and genito-urinary systems. The common gastrointestinal tract bifurcated at the level of the jejunum. Our case documents a very uncommon variety of asymmetrical cephalothoracopagus janiceps with duplicated central nervous systems.

Adult↗
PubMed1997

Prenatal diagnosis of partial trisomy 12 and partial trisomy 21 due to a 3:1 segregation of maternal reciprocal translocation t(12;21) (p13.3;q21).

We describe the prenatal diagnosis and fetal phenotype of partial trisomy 12 (p13.3-pter) and partial trisomy 21 (pter-q21) due to a 3:1 segregation with tertiary aneuploidy transmitted from a maternal reciprocal translocation 12;21. Genetic amniocentesis of a 39-year-old gravida 2, para 1 woman at 19 weeks' gestation due to advanced maternal age revealed an unusual karyotype of 47,XY,+der(21)t(12;21)(p13.3;q21)mat. The pregnancy was terminated at 24 gestational weeks. The proband postnatally displayed by dysmorphic features of a round flat face with prominent cheeks and high forehead, upward slanting palpebral fissures, epicanthic folds, hypertelorism, a short nose, a broad and depressed nasal bridge, anteverted nares, a deformed philtrum, an open mouth, thin upper vermilion and broad everted lower lip, low-set ears with prominent anthelix and deep concha, broad hands with simian creases, a short neck, and cryptorchidism. The association of the involved chromosomal segments with the phenotype of Down's syndrome and trisomy 12p syndrome is discussed.

Adult↗
PubMed1997

Isolation, characterization, and chromosomal mapping of a novel cDNA clone encoding human selenium binding protein.

We have isolated the full-length human 56 kDa selenium binding protein (hSP56) cDNA clone, which is the human homolog of mouse 56 kDa selenium binding protein. The cDNA is 1,668 bp long and has an open reading frame encoding 472 amino acids. The calculated molecular weight is 52.25 kDa and the estimated isoelectric point is 6.13. Using Northern blot hybridization, we found that this 56 kDa selenium binding protein is expressed in mouse heart with an intermediate level between those found in liver/lung/kidney and intestine. We have also successfully expressed hSP56 in Escherichia coli using the expression vector-pAED4. The hSP56 gene is located at human chromosome 1q21-22).

Amino Acid Sequence↗
PubMed1997

Estrogen-induced cyclin D1 and D3 gene expressions during mouse uterine cell proliferation in vivo: differential induction mechanism of cyclin D1 and D3.

D-type cyclins are involved in the regulation of the G1/S transition of the cell cycle in various cell types cultured in vitro. Little is, however, known about the expression pattern and functional role of D-type cyclins in physiological processes in vivo. In this report, we studied whether the expression of murine D-type cyclins correlates with the states of mouse uterine cell proliferation in vivo. Time-course changes in cyclin D1 and D3 mRNA levels in the uterine tissues of immature mice primed with 17 beta-estradiol (E2) were examined by Northern blot hybridization. c-fos and thymidine kinase (TK) mRNA levels were also examined as markers for the transition from G0 to G1 and the onset of S phase, respectively. Cyclin D1 and D3 mRNAs were induced 2.5-fold between c-fos and TK mRNA peaks. The E2-induced cyclin D1 and D3 gene expressions were blocked by antiestrogens tamoxifen and ICI 182,780. We also investigated the effects of cycloheximide (CHX), a protein synthesis inhibitor, on cyclin D1 and D3 gene expressions. When CHX was treated alone, cyclin D3, but not cyclin D1, mRNA was immediately superinduced. The E2-induced cyclin D3 gene expression was shifted by approximately 6 h when CHX was pretreated 1 hr before E2 administration. Interestingly, the 3H-thymidine incorporation experiment showed that the mouse uterine cell cycle progression also shifted by 6 hr with pretreatment of CHX. The overall results suggest that both cyclin D1 and D3 mRNAs are constitutively expressed in uterine tissues and induced by E2 at G1 phase of the mouse uterine cell cycle. However, the superinducibility and temporal shift of cyclin D3 by CHX suggest that there is a different regulatory mechanism underlying cyclin D1 and D3 gene expressions in the mouse uterine cell cycle progression.

Animals↗
PubMed1997

Optic atrophy and cerebral infarcts caused by methanol intoxication: MRI.

We present the MRI findings of cerebral and optic pathway damage in the acute and subacute stages of methanol intoxication. In the acute stage, CT and MRI showed bilateral haemorrhagic necrosis of the corpus striatum and infarcts in the anterior and middle cerebral arterial territories. MRI in the subacute stage demonstrated atrophy of the optic chiasm and prechiasmatic optic nerves in addition to the cerebral infarcts. The patient survived, with total blindness.

Adult↗
PubMed1997

Two partial deletion mutations involving the same Alu sequence within intron 8 of the LDL receptor gene in Korean patients with familial hypercholesterolemia.

Twenty-eight unrelated persons heterozygous for familial hypercholesterolemia (FH) were screened to assess the frequency and nature of major structural rearrangements at the low-density lipoprotein (LDL) receptor gene in Korean FH patients. Genomic DNA was analyzed by Southern blot hybridization with probes encompassing exons 1-18 of the LDL receptor gene. Two different deletion mutations (FH29 and FH110) were detected in three FH patients (10.7%). Each of the mutations was characterized by the use of exon-specific probes and detailed restriction mapping mediated by long-PCR (polymerase chain reaction). Mutation FH29 was a 3.83-kb deletion extending from intron 6 to intron 8 and FH110 was a 5.71-kb deletion extending from intron 8 to intron 12. In FH29, the translational reading frame was preserved and the deducible result was a cysteine-rich A and B repeat truncated protein that might be unable to bind LDL but would continue to bind beta-VLDL. FH110 is presumed to be a null allele, since the deletion shifts the reading frame and results in a truncated protein that terminates in exon 13. Sequence analysis revealed that both deletions have occurred between two Alu-repetitive sequences that are in the same orientation. This suggested that in these patients the deletions were caused by an unequal crossing over event following mispairing of two Alu sequences on different chromatids during meiosis. Moreover, in both deletions, the recombinations were related to an Alu sequence in intron 8 and the deletion breakpoints are found within a specific sequence, 27 bp in length. This supports the hypothesis that this region might have some intrinsic instability, and act as one of the important factors in large recombinational rearrangements.

Adolescent↗