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Biomedical subjects

J R Wu

Publications and source records attributed to J R Wu.

At least 91 records · Page 5Linked to original sources
PubMed1989

[Relapse of Kawasaki disease: a case report].

Reports of the relapse in Kawasaki disease is rare in the literature. Prior to this study, it had never been reported in Taiwan. In November 1986, a 15-month-old boy developed a persistent high fever, dry red lips, conjunctivitis, neck lymph node swelling, erythema, indurated edema and desquamation of the perianal area and in areas of the palms and soles. A diagnosis of Kawasaki disease was made. Two dimensional echocardiography and cineangiography disclosed a fusiform aneurysmal dilatation of the right and left coronary arteries. He was treated with aspirin for 7 months. Nine months after the first attack of the illness, he again developed a persistent moderate rise of temperature, conjunctivitis, red lips, reddish swelling and desquamation of his palms. He was suffering from a second attack of Kawasaki disease. When comparing the clinical manifestations observed during the first attack and during the relapse of Kawasaki disease in this case, the duration of fever was found to be shorter and the severity of swelling and desquamation of palms milder.

Coronary Aneurysm↗
PubMed1988

A highly conserved repetitive DNA sequence, (TTAGGG)n, present at the telomeres of human chromosomes.

A highly conserved repetitive DNA sequence, (TTAGGG)n, has been isolated from a human recombinant repetitive DNA library. Quantitative hybridization to chromosomes sorted by flow cytometry indicates that comparable amounts of this sequence are present on each human chromosome. Both fluorescent in situ hybridization and BAL-31 nuclease digestion experiments reveal major clusters of this sequence at the telomeres of all human chromosomes. The evolutionary conservation of this DNA sequence, its terminal chromosomal location in a variety of higher eukaryotes (regardless of chromosome number or chromosome length), and its similarity to functional telomeres isolated from lower eukaryotes suggest that this sequence is a functional human telomere.

Base Sequence↗
PubMed1984

Percutaneous balloon aortic valvuloplasty: results in 23 patients.

Percutaneous balloon aortic valvuloplasty (BAV) was performed in 23 consecutive patients with valvular aortic stenosis with no associated cardiac defects. The patients were 2 to 17 years old and were referred from 12 hospitals in 4 states. The balloon was positioned across the aortic valve and inflated to pressures of 80, 100, then 120 psi. Each inflation lasted 5 to 10 seconds. The arterial and venous catheters were connected together outside the groin to avoid excessive increase in left ventricular pressure during total aortic valve occlusion with the inflated balloon. Peak systolic aortic valve pressure gradient and cardiac output were measured before and 15 minutes after BAV. There was no significant change in cardiac output, but all patients had a lessened gradient. The gradient before BAV was 113 +/- 48 mm Hg, decreasing to 32 +/- 15 mm Hg after BAV (p less than 0.01). The left ventricular peak systolic pressure decreased from 221 +/- 54 to 149 +/- 21 mm Hg (p less than 0.01). No aortic regurgitation was noted in 13 patients and very mild aortic regurgitation was noted in 10 patients after BAV. The balloons were 10 to 20 mm in diameter, chosen at least 1 mm smaller than the diameter of the aortic valve anulus. Pressures of 100 to 120 psi were required to achieve full inflation of the balloons. Six patients had repeat cardiac catheterization studies 3 to 9 months after BAV. In none was there a significant change in peak systolic aortic valve pressure gradient or cardiac output compared with the study immediately after valvuloplasty.

Adolescent↗
PubMed1984

Genetic analysis of dar, uvsW, and uvsY in bacteriophage T4: dar and uvsW are alleles.

A genetic study of the T4 dar (DNA arrested synthesis restoration) mutations was performed by two- and three-factor crosses. The dar mutations restore the viability of gene 59 mutants. Mapping studies of the dar mutations indicated that the dar gene extended over 16 map units. This high recombination frequency is attributed to an increased level of recombination in the dar region. Two other mutations, uvsY and uvsW, known to be located in the vicinity of dar, were studied. These studies indicated that the uvsY and dar mutations were located in separate genes but that dar and uvsW were allelic. The genes are ordered as follows: gene 24, dar(uvsW), uvsY, and gene 25 in clockwise order.

Alleles↗
PubMed1984

Methylation of the alpha-fetoprotein gene in productive and nonproductive rat hepatocellular carcinomas.

The extent of methylation of Hpall-Mspl and Hhal sites in DNAs isolated from normal rat livers and from the transplantable hepatocellular carcinomas (THC) THC 7777 and THC 252 was compared. It was found that the overall level of methylation of the internal cytosine in CCGG sequences was lower in the THC DNAs than in the normal liver DNAs. This difference could also be detected in the extent of methylation of CCGG sites flanking a 400-base pair repetitive sequence. Examination of methylation of specific sites within the alpha-fetoprotein gene revealed differences between the DNAs that appear to reflect both the level of activity of the gene and the overall level of methylation of cellular DNA. This gene, which is repressed in normal adult liver and the nonproductive THC 252 and highly active in the productive THC 7777 (S. Sell et al., Cell Biol. Int. Rep., 4: 235-254, 1980), contains several CCGG sites that are methylated in both normal liver and THC 252 DNA but not in THC 7777 DNA. However, Hhal (GCGC) sites in the alpha-fetoprotein gene were less methylated in both hepatoma DNAs than in liver DNA, which the exception of one site in the productive tumor found to be no longer methylated.

Animals↗
PubMed1983

Percutaneous balloon pulmonary valvuloplasty.

Percutaneous balloon pulmonary valvuloplasty (BPV) was performed in 18 consecutive patients with valvular pulmonary stenosis (PS) with no associated cardiac defects. The patients were 11 months to 19 years of age. The balloon was positioned across the pulmonary valve and inflated to pressures of 80, 100, and 120 pounds/square inch (psi). Each inflation lasted approximately 10 seconds. Peak systolic pulmonary valve gradient (delta P) and cardiac output were measured before and 15 minutes after BPV. There was no change in cardiac output, but all patients had an improved delta P. The prevalvuloplasty delta P was 81 +/- 31 mm Hg, decreasing to 23 +/- 11 mm Hg after BPV (p less than 0.01). The right ventricular peak systolic pressure decreased from 106 +/- 31 to 50 +/- 12 mm Hg (p less than 0.01). No pulmonary regurgitation was noted after BPV. The balloons were 12 or 15 mm in diameter, chosen according to the diameter of the pulmonary valve anulus. Pressures of 100 to 120 psi were required to achieve full inflation of the balloons. BPV also was performed in a patient with tetralogy of Fallot. Subsequent total repair provided an opportunity to observe the mechanism of the dilatation. Evidence of a small tear alongside the anterior valve raphe was noted. BPV induced a significant decrease in delta P and may offer an alternative method for treating PS.

Adolescent↗
PubMed1979

Determination of the size of rat ribosomal deoxyribonucleic acid repeating units by electron microscopy.

The empoyment of a novel method of affinity chromatography, which makes use of antibodies that specifically bind DNA/RNA hybrids, has made it possible to enrich for rat rDNA molecules which contain R loops formed with the 18S and 28S rRNAs. An approximately 150-fold enrichment of the ratrRNA coding sequences was obtained by this affinity chromatography procedure. This degree of enrichment made it possible to visualize these R loop containing molecules in the electron microscope and, thus, to obtain a map of the transcribed and spacer regions of rat rDNA. Eleven of the molecules that were observed contained either 3 or 4 R loops, or else 2 R loops separated by a long spacer. Thus, these molecules provided direct information in regard to the length of rat rDNA repeating units. The mean length of the repeating units was 37.2 kbp with a standard deviation of 1.3 kbp. Within the errors of the measurements, these could all represent repeating units of exactly the same length, although a certain degree of length heterogeneity, possibly up to 4 or 5 kbp, cannot be ruled out by the data. If significantly longer or shorter rDNA repeating units exist in the rat genome, they are probably much less common than the 37.2 kbp unit. These electron microscopic measurements provide the most definitive data yet available on the size of the repeating units of mammalian rRNA genes.

Animals↗
PubMed1979

The rat serum albumin gene: analysis of cloned sequences.

The rat serum albumin gene has been isolated from a recombinant library containing the entire rat genome cloned in the lambda phage Charon 4A. Preliminary R-loop and restriction analysis has revealed that this gene is split into at least 14 fragments (exons) by 13 intervening sequences (introns), and that it occupies a minimum of 14.5 kilobases of genomic DNA.

Animals↗
PubMed1978

Gene enrichment using antibodies to DNA/RNA hybrids: purification and mapping of Dictyostelium discoideum rDNA.

Antibodies, shown to be specific for DNA/RNA hybrids, have been covalently attached to CNBr-activated Sepharose. The resultant affinity resin specifically binds DNA/RNA hybrids and has been used to enrich for the DNA which codes for rRNA in the slime mold Dictyostelium discoideum. By utilizing the technique of R-loop formation, DNA molecules containing the rRNA genes were isolated from total nuclear DNA in a double-stranded form. These rDNA molecules, which were recovered by high salt elution from the affinity resin, were typically 15-40 kbp in length, and thus contained DNA sequences adjacent to the selected sequences coding for the 17S and 26S rRNAs. In addition, evidence has been obtained concerning the structure of Dictyostelium rDNA which agrees with the finding (Taylor et al. (1977) ICN-UCLA Symp. Mol. Cell. Biol. 8, 309-313) that the rDNA molecules are not covalently attached to the chromosomes of this organism.

Chromatography, Affinity↗
PubMed1978

Analysis of rat repetitive DNA sequences.

Parameters of repetitive sequence organization have been measured in the rat genome. Experiments using melting, hydroxylapatite binding, and single strand specific nuclease digestion have been used to measure the number, length, and arrangement of repeated DNA sequences. Renaturation and melting or S1 nuclease digestion of 1.0 kbp DNA fragment show about 20% of rat DNA sequences are 3000-fold repeated. Renatured duplexes from 4.0 kbp DNA fragments display two repetitive size fractions after nuclease digestion. About 60% of the repeated sequences are 0.2-0.4 kbp long while the remainder are longer than 1.5 kbp. The arrangement of the repeated sequences has been measured by hydroxylapatite fractionation of DNA fragments of varying lengths bearing a repeated sequence. Repeated DNA sequences are interspersed among 2.5 kbp long nonrepeated sequences throughout more than 70% of the rat genome. There are approximately 350 different 3000-fold short repeated sequences in the rat interspersed among 600,000 nonrepeated DNA sequences.

Animals↗
PubMed1978

Sequence organization of the rat genome by electron microscopy.

The size and arrangement of repetitive and inverted repeat (foldback) sequences in rat DNA were studied by visualization of hybrid and heteroduplex structures in the electron microscope. The self-reassociation of repetitive sequence-bearing DNA strands often results in the formation of four-ended "H" structures, whose duplex regions equal the repetitive sequence length and can be measured in the electron microscope. In this way, it was determined that the average size of the class of numerous short repetitive sequences is 0.40 +/- 0.15 kbp. Heteroduplex structures were prepared between long whole DNA single strands and short repeat-sequence-bearing strands. The analysis of these structures confirms that the size of the repetitive sequences in 0.4 kbp on average. Length measurements between adjacent duplexes show that the average spacing between two interspersed repeats is at least 1.5-1.8 kbp. By examining 29.4-kbp single strands after brief renaturation, the size and distribution of foldback sequences were determined. There are 1.9 X 10(5) foldback apirs per rat genome, spaced an average of 9.7 kbp apart according to our measurement. Repetitive, inverted repeat and unique sequences are interspersed with each other in at least half the genome.

Animals↗