Search PubMed⌕ Search

Biomedical subjects

Y L Chan

Publications and source records attributed to Y L Chan.

At least 109 records · Page 6Linked to original sources
PubMed1996

The primary structure of rat ribosomal protein L6.

The amino acid sequence of the rat 60S ribosomal subunit protein L6 was deduced from the sequence of nucleotides in a recombinant cDNA and confirmed by determination of amino acid sequences in the protein. Ribosomal protein L6 has 296 amino acids (the NH2-terminal methionine is removed after translation of mRNA); the molecular weight is 33,417. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 7 to 10 copies of the L6 gene. The mRNA for the protein is about 1,100 nucleotides in length. Rat L6 is related to ribosomal proteins from other eukaryotes and to histone H1.

Amino Acid Sequence↗
PubMed1996

Choledocholithiasis: comparison of MR cholangiography and endoscopic retrograde cholangiography.

PURPOSE: To prospectively compare magnetic resonance (MR) cholangiography with endoscopic retrograde cholangiography (ERC) in the diagnosis of choledocholithiasis. MATERIALS AND METHODS: Forty-seven patients with suspected choledocholithiasis underwent non-breath-hold, heavily T2-weighted, respiratory-triggered turbo spin-echo MR cholangiography. They then underwent ERC within 5 hours. The results of the two procedures were compared in 45 patients. RESULTS: The absence of ductal dilatation was shown in 16 patients at MR cholangiography and at ERC. MR cholangiography showed common duct dilatation in 28 of the 29 patients with dilatation shown at ERC. MR cholangiography helped correctly identify 18 of the 19 patients with choledocholithiasis and 22 of the 26 patients without choledocholithiasis. Sensitivity with MR cholangiography was 95%, specificity was 85%, positive predictive value was 82%, and negative predictive value was 96%. Two of the false-positive findings were due to pneumobilia. CONCLUSION: Non-breath-hold MR cholangiography is as accurate for the evaluation of choledocholithiasis as ERC.

Adult↗
PubMed1996

Variability of magnetic resonance angiography and computed tomography angiography in grading middle cerebral artery stenosis.

BACKGROUND AND PURPOSE: Magnetic resonance angiography and computed tomography angiography are new, noninvasive methods to provide images of the cerebral vasculature. The reliability of magnetic resonance angiography and computed tomography angiography when used to grade middle cerebral artery stenosis remains to be established. We sought to study the interobserver and intraobserver variabilities of magnetic resonance angiography and computed tomography angiography in grading middle cerebral artery stenosis. METHODS: A total of 50 middle cerebral arteries in 25 patients were studied with magnetic resonance angiography and computed tomography angiography. All patients had a history of ischemic stroke. The films were read independently by two observers on separate occasions. Films were shown again to the same observer 4 weeks after the first reading. The degree of middle cerebral artery stenosis was categorized into four grades: normal/mild, moderate, severe, and occluded. The interobserver and intraobserver variabilities were calculated by the kappa statistic method. RESULTS: Interobserver variability for grading middle cerebral artery stenosis was good (kappa = 0.78) for magnetic resonance angiography and moderate (kappa = 0.51) for computed tomography angiography. There was perfect agreement between two observers in 86% of the vessels shown in magnetic resonance angiography and in 76% of the vessels shown in computed tomography angiography. Intraobserver variability for both imaging methods was good, with the kappa value in the range of 0.70 to 0.76. CONCLUSIONS: Our results suggest that according to our protocol, magnetic resonance angiography is more reliable than computed tomography angiography in grading middle cerebral artery stenosis.

Adult↗
PubMed1996

Role of MIBI breast scintigraphy in evaluation of palpable breast lesions.

The sensitivity and specificity of MIBI breast scintigraphy, conventional mammography and ultrasound in differentiating malignant and benign palpable breast lesions was compared in 48 women. MIBI breast scintigraphy had a sensitivity of 97% a specificity of 69%, a positive predictive value of 87.5% and a negative predictive value of 91.7%. Ultrasound and mammography had comparable results with accuracy rates of approximately 93%. We conclude that MIBI breast scintigraphy may have a complementary role in the evaluation of palpable breast lesions, but is not specific enough to replace current imaging modalities.

Adult↗
PubMed1995

The carboxyl extensions of two rat ubiquitin fusion proteins are ribosomal proteins S27a and L40.

Two rat recombinant cDNAs were characterized; they encode fusion proteins that have at their NH2 terminus the conserved 76 amino acid ubiquitin and at their carboxyl terminus the extension ribosomal proteins S27a (80 amino acids and a molecular weight of 9,397) or L40 (52 amino acids and a molecular weight of 6,177). The fusion proteins are processed in a reticulocyte lysate to ubiquitin and either S27a or L40. Hybridization of cDNAs to digests of nuclear DNA suggests that there are 14 to 19 copies of the S27a, and 6 to 10 of the L40, genes. The mRNA for ubiquitin-S27a has about 700 nucleotides and ubiquitin-L40 about 650. Ribosomal proteins S27a and L40 contain zinc finger motifs of the C2-C2 variety. S27a and L40 are related to ribosomal proteins from other species.

Amino Acid Sequence↗
PubMed1995

The primary structures of rat ribosomal proteins L4 and L41.

The amino acid sequences of the rat 60S ribosomal subunit proteins L4 and L41 were deduced from the sequences of nucleotides in recombinant cDNAs. Ribosomal protein L4 has 421 amino acids; the molecular weight is 47,280. L41 is the smallest ribosomal protein; it has 25 amino acids and a molecular weight of 3,454. Hybridization of the cDNAs to digests of nuclear DNA suggests that there are 7 to 8 copies of the L4, and 9 to 12 of the L41, genes. The mRNA for L4 is about 1,500 nucleotides in length and that for L41 about 500 nucleotides. The 5' noncoding sequence of the L4 cDNA is exceptional in that it has, in addition to a short polypyrimidine sequence at the 5' end, a second stretch of 15 consecutive pyrimidines near the site of initiation of translation. The 3' noncoding sequence of the L41 mRNA is unusual in that it is at least 246 nucleotides long. Rat L4 and L41 are related to ribosomal proteins from other eukaryotes.

Amino Acid Sequence↗
PubMed1995

The primary structures of rat ribosomal proteins: the characterization of the cDNAs for S21 and L39, corrections in the sequences of L7 and L18a, and the identification of L33.

cDNAs for rat ribosomal proteins S21 and L39 were characterized. S21 has 83 amino acids and a molecular weight of 9,121; L39 has 50 amino acids and a molecular weight of 6,271. There are 8 to 9 copies of the S21, and 9 to 11 copies of the L39 genes. The mRNA for S21 is about 500 nucleotides in length and for L39 it is about 450. Rat S21 and L39 are related to ribosomal proteins from other species. Corrections have been made in the amino acid sequences of L7 and L18a. The rat ribosomal protein designated L33 from its coordinates on two-dimensional gels has been found, from its amino acid sequence, to be identical to S24.

Amino Acid Sequence↗
PubMed1995

The primary structure of rat ribosomal protein L22.

The amino acid sequence of the rat 60S ribosomal subunit protein L22 was deduced from the sequence of nucleotides in two recombinant cDNAs. Ribosomal protein L22 has 128 amino acids; the molecular weight is 14,779. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 6 to 9 copies of the L22 gene. The mRNA for the protein is about 600 nucleotides in length. Rat L22 is related to ribosomal proteins from other eukaryotes and is identical in amino acid sequence to human EAP, the EBER 1 (Epstein-Barr virus encoded RNA) associated protein.

Amino Acid Sequence↗
PubMed1994

The primary structure of rat ribosomal protein L24.

The amino acid sequence of the rat 60S ribosomal subunit protein L24 was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein L24 has 157 amino acids; the molecular weight is 17,767. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 9 to 11 copies of the L24 gene. The mRNA for the protein is about 650 nucleotides in length. Rat L24 is related to ribosomal proteins from other eukaryotes and from archaebacteria.

Amino Acid Sequence↗
PubMed1994

The primary structure of rat ribosomal protein S15a.

The amino acid sequence of the rat 40S ribosomal subunit protein S15a was deduced from the sequence of nucleotides in two recombinant cDNAs. Ribosomal protein S15a has 129 amino acids, the NH2-terminal methionine is removed after translation of the mRNA and has a molecular weight of 14,698. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 10 to 15 copies of the S15a gene. The mRNA for the protein is about 650 nucleotides in length. Rat S15a is related to ribosomal proteins from other eukaryotes, from eubacteria, and from archaebacteria.

Amino Acid Sequence↗
PubMed1994

A leucine zipper-like motif and a basic region-leucine zipper-like element in rat ribosomal protein L13a. Identification of the tum- transplantation antigen P198.

The amino acid sequence of the rat 60 S ribosomal subunit protein L13a was deduced from the sequence of nucleotides in two recombinant cDNAs. Mature ribosomal protein L13a has 202 amino acids (the NH2-terminal methionine is removed after translation of the mRNA) and a M(r) of 23,330. Hybridization of the L13a cDNA to digests of nuclear DNA suggests that there are 9-11 copies of the L13a gene. The mRNA for the protein is approximately 800 nucleotides in length. Rat L13a is related to the Saccharomyces cerevisiae ribosomal proteins that have been provisionally designated rp22 and rp23 and to the eubacterial and archaebacterial family of L13 ribosomal proteins. The mouse tum- transplantation antigen P198 is a mutant of the mouse homolog of rat ribosomal protein L13a. Rat ribosomal protein L7 has, at its NH2 terminus, five tandem repeats of a similar sequence of 12 amino acids (Lin, A., Chan, Y. L., McNally, J., Peleg, D., Meyuhas, O., and Wool, I. G. (1987) J. Biol. Chem. 262, 12665-12671); L13a has, in its carboxyl-terminal region, amino acid sequences with significant identity to L7 repeats 1, 3, and 5. L13a also has a number of short amino acid sequences that are repeated, a leucine zipper-like motif at its NH2 terminus, and a potential basic region-leucine zipper element in its carboxyl-terminal region.

Amino Acid Sequence↗
PubMed1994

Acute scrotal swelling: a sign of neonatal adrenal haemorrhage.

Two neonates presented with acute scrotal swelling suggestive of testicular torsion. Surgical exploration in one patient revealed an infected haematoma. Subsequent investigations including ultrasonography and urinary catecholamine determination disclosed adrenal haemorrhage as the cause of the scrotal haematoma. A second patient in whom a purplish discolouration of the right hemiscrotum was noted was also investigated with ultrasonography, which revealed a normal right testis and a right adrenal haematoma. Both cases of adrenal haemorrhage resolved spontaneously on conservative treatment. Adrenal haemorrhage should be considered as a possible cause of acute scrotal swelling in neonates. Ultrasonography assessment should be performed in such cases to examine the intra-abdominal organs especially the adrenal glands.

Abscess↗
PubMed1993

The primary structure of rat ribosomal protein S9.

The amino acid sequence of the rat 40S ribosomal subunit protein S9 was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein S9 has 193 amino acids, the NH2-terminal methionine is removed after translation of the mRNA, and has a molecular weight of 22,360. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 14 to 16 copies of the S9 gene. The mRNA for the protein is about 1,000 nucleotides in length in part because of an especially long 5' noncoding region (103 nucleotides). Rat S9 is related to ribosomal proteins from other eukaryotes, Saccharomyces cerevisiae YS11 and Dictyostelium discoideum rp 1024, and to the eubacterial, archaebacterial, and chloroplast family of S4 ribosomal proteins. We have identified the product of the Trypanosoma brucei gene U as the homolog of rat ribosomal protein S9.

Amino Acid Sequence↗
PubMed1993

The primary structure of rat ribosomal protein L29.

The amino acid sequence of the rat 60S ribosomal subunit protein L29 was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein L29 has 155 amino acids, the NH2-terminal methionine is removed after translation of the mRNA, and has a molecular weight of 17,183. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 20 to 22 copies of the L29 gene. The mRNA for the protein is about 750 nucleotides in length. Rat L29 is related to yeast ribosomal protein YL43.

Amino Acid Sequence↗
PubMed1993

The primary structure of L37--a rat ribosomal protein with a zinc finger-like motif.

The amino acid sequence of the rat 60S ribosomal subunit protein L37 was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein L37 has 96 amino acids, the NH2-terminal methionine is removed after translation of the mRNA, and has a molecular weight of 10,939. Ribosomal protein L37 has a single zinc finger-like motif of the C2-C2 type. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 13 or 14 copies of the L37 gene. The mRNA for the protein is about 500 nucleotides in length. Rat L37 is related to Saccharomyces cerevisiae ribosomal protein YL35 and to Caenorhabditis elegans L37. We have identified in the data base a DNA sequence that encodes the chicken homolog of rat L37.

Amino Acid Sequence↗
PubMed1993

The primary structure of rat ribosomal protein L36.

The amino acid sequence of the rat 60S ribosomal subunit protein L36 was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein L36 has 104 amino acids, the NH2-terminal methionine is removed after translation of the mRNA and has a molecular weight of 12,128. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 8 to 11 copies of the L36 gene. The mRNA for the protein is about 500 nucleotides in length. Rat L36 is related to yeast ribosomal protein YL39.

Amino Acid Sequence↗
PubMed1993

Zinc finger-like motifs in rat ribosomal proteins S27 and S29.

The primary structures of the rat 40S ribosomal subunit proteins S27 and S29 were deduced from the sequences of nucleotides in recombinant cDNAs and confirmed by determination of amino acid sequences in the proteins. Ribosomal protein S27 has 83 amino acids and the molecular weight is 9,339. Hybridization of cDNA to digests of nuclear DNA suggests that there are 4-6 copies of the S27 gene; the mRNA for the protein is about 620 nucleotides in length. Ribosomal protein S29 has 55 amino acids and the molecular weight is 6,541. There are 14-17 copies of the S29 gene and its mRNA is about 500 nucleotides in length. Rat ribosomal protein S29 is related to several members of the archaebacterial and eubacterial S14 family of ribosomal proteins. S27 and S29 have zinc finger-like motifs as do other proteins from eukaryotic, archaebacterial, eubacterial, and mitochondrial ribosomes. Moreover, ribosomes and ribosomal subunits appear to contain zinc and iron as well.

Amino Acid Sequence↗