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J Yu

Publications and source records attributed to J Yu.

At least 703 records · Page 39Linked to original sources
PubMed1994

Construction and characterization of region-specific microdissection libraries and single-copy microclones for short arm of human chromosome 2.

The short arm of human chromosome 2, comprising approximately 93 million bp, has been divided into four regions to construct region-specific microdissection libraries to facilitate physical mapping and gene cloning. These four regions include 2p23-p25 (designated 2P1), 2p21-p23 (2P2), 2p14-p16 (2P3), and 2p11-p13 (2P4). Together with three previously constructed microdissection libraries of 2P1, 2P2 and 2P4, a fourth library for the region 2p14-p16 (2P3) has been constructed and characterized to complete all four region-specific libraries for the entire 2p. The 2P3 library is very large, potentially comprising 1,000,000 recombinant microclones with insert sizes ranging between 50 and 800 bp and a mean of 250 bp. Approximately 40% of the microclones contain unique sequences. Of the 77 single-copy microclones analyzed, 66 clones (86%) hybridized to both human and chromosome 2 DNAs, indicating that they were derived from human and are chromosome 2 specific. The hybridizing HindIII genomic fragments for the 66 microclones have also been determined.

Blotting, Southern↗
PubMed1994

Region-specific microdissection library and single-copy microclones for human chromosome 2p11-p13.

We report the construction and characterization of a region-specific microdissection library for human chromosome 2p11-p13. This library (designated 2P4 library) is large, comprising 600,000 recombinant microclones. Thirty to 40% of the clones contain unique sequences. The insert sizes range from 100 to 800 bp, with a mean of 380 bp. A subset of the microclones was selected, based on their weak or no hybridization to total human DNA, for further analysis. Of 50 single-copy microclones analyzed, 35 clones (70%) were derived from human and are chromosome 2-specific. The insert sizes and the hybridizing genomic HindIII fragments of these clones were also determined. The 2P4 microdissection library and the single-copy microclones from the library are useful in preparing STS (sequence-tagged site) to isolate corresponding YAC (yeast artificial chromosome) or other clones with large inserts and for isolating region-specific cDNA clones as candidate genes for cloning disease-related genes assigned to this region.

Chromosomes, Human, Pair 2↗
PubMed1994

Adhesion of coagulase-negative staphylococci and adsorption of plasma proteins to heparinized polymer surfaces.

Protease treatment of cells of coagulase-negative staphylococci reduced the adhesion of bacteria to heparinized polyethylene preadsorbed with serum. Fibronectin (Fn), fibrinogen (Fg), vitronectin, complement factor C3c, plasminogen, laminin and to a low extent albumin were detected on tridodecylmethylammonium chloride (TDMAC)-heparinized polyvinyl chloride (PVC) catheters extirpated from the circulation of patients. Using a perfusion model we show that during the first hours of perfusion with human plasma, Fn and Vn dominate, whereas after 22 h of perfusion Fg is the dominant protein. Field emission scanning electron microscopy and atomic force microscopy studies on TDMAC-heparinized catheters as well as on end-point attached heparinized PVC catheters indicate that quantitatively more Fg than Fn is exposed on these surfaces after prolonged exposure (> 22 h) to human plasma.

Adsorption↗
PubMed1994

Studying human mutations by sperm typing: instability of CAG trinucleotide repeats in the human androgen receptor gene.

Trinucleotide repeat mutations of normal alleles at the human androgen receptor locus were studied by typing approximately 4,300 sperm. Control experiments established that the mutation events were of germline origin. The mutation rate for 20-22 repeat alleles was similar to that shown by family analysis. Alleles with 28-31 repeats had a 4.4 times greater rate of mutation with contractions outnumbering expansions. Preliminary experiments on the trinucleotide repeat associated with myotonic dystrophy gave similar results although in one donor expansions were six times greater than contractions. Comparison of the sperm data to mutations of disease alleles in SBMA families suggests that expansions may have a different origin than contractions.

Alleles↗
PubMed1994

Uroplakins Ia and Ib, two major differentiation products of bladder epithelium, belong to a family of four transmembrane domain (4TM) proteins.

The mammalian bladder epithelium elaborates, as a terminal differentiation product, a specialized plasma membrane called asymmetric unit membrane (AUM) which is believed to play a role in strengthening and stabilizing the urothelial apical surface through its interactions with an underlying cytoskeleton. Previous studies indicate that the outer leaflet of AUM is composed of crystalline patches of 12-nm protein particles, and that bovine AUMs contain three major proteins: the 27- to 28-kD uroplakin I, the 15-kD uroplakin II and the 47-kD uroplakin III. As a step towards elucidating the AUM structure and function, we have cloned the cDNAs of bovine uroplakin I (UPI). Our results established the existence of two isoforms of bovine uroplakin I: a 27-kD uroplakin Ia and a 28-kD uroplakin Ib. These two glycoproteins are closely related with 39% identity in their amino acid sequences. Hydropathy plot revealed that both have four potential transmembrane domains (TMDs) with connecting loops of similar length. Proteolytic digestion of UPIa inserted in vitro into microsomal vesicles suggested that its two main hydrophilic loops are exposed to the luminal space, possibly involved in interacting with the luminal domains of other uroplakins to form the 12-nm protein particles. The larger loop connecting TMD3 and TMD4 of both UPIa and UPIb contains six highly conserved cysteine residues; at least one centrally located cysteine doublet in UPIa is involved in forming intramolecular disulfide bridges. The sequences of UPIa and UPIb (the latter is almost identical to a hypothetical, TGF beta-inducible, TI-1 protein of mink lung epithelial cells) are homologous to members of a recently described family all possessing four transmembrane domains (the "4TM family"); members of this family include many important leukocyte differentiation markers such as CD9, CD37, CD53, and CD63. The tissue-specific and differentiation-dependent expression as well as the naturally occurring crystalline state of uroplakin I molecules make them uniquely suitable, as prototype members of the 4TM family, for studying the structure and function of these integral membrane proteins.

Amino Acid Sequence↗
PubMed1994

The measurement of the lateralization of narrow bands of noise using an acoustic pointing paradigm: the effect of sound-pressure level.

The effects of varying interaural time delay (ITD) and interaural intensity difference (IID) were measured in normal-hearing subjects as a function of eleven frequencies and at sound-pressure levels (SPL) from 60 to 90 dB SPL and at 25-dB sensation level. Using an "acoustic" pointing paradigm, the IID of a 500-Hz narrow-band (100 Hz) noise (the "pointer") was varied by the subject to coincide with that of a "target" ITD stimulus. ITDs of 0, +/- 200, and +/- 400 microseconds were obtained through total waveform delays of narrow-band noise (NBN), including envelope and fine structure. The results of this experiment confirm the traditional view of binaural hearing for like stimuli: There is little perceived displacement away from 0 IID at frequencies of 1250 Hz and above. In the low frequencies, subjects required IIDs greater than the expected 10 dB to perceive a fully lateralized image, and they varied in the maximum value of IID that they required, regardless of frequency. Our subjects did not always perceive the intracranial locations of ITD targets symmetrically: When the signal was delayed to one ear, the resultant matching IID was often different in magnitude than for the same ITD target delayed to the opposite ear for the identical frequency. The results of two subjects suggested that people with asymmetric normal hearing have adapted to their asymmetry for lateralization tasks: The subjects were found to lateralize toward the ear with the greater SPL stimulus, regardless of the ear to which the signal was delayed, when signals of equal SL were presented, and toward the leading ear when signals of equal SPL were presented (unequal SL). Increasing the presentation levels above 60 dB SPL had an effect on the perception of high-frequency ITD targets: As the intensity level increased, the slopes of the IID versus ITD functions increased indicating better discrimination of ITD. This study is in agreement with other studies in providing strong evidence of individual differences in lateralization experiments. These individual differences might be attributable to differential sensitivity to ambiguous time stimulus cues, differential task sensitivity, age effects, threshold asymmetries, or criterion variability.

Adult↗
PubMed1994

MR imaging evaluation of liver enhancement by Gd-EOB-DTPA in selective and total bile duct obstruction in rats: correlation with serologic, microcholangiographic, and histologic findings.

PURPOSE: To investigate the behavior and potential application of the hepatobiliary magnetic resonance (MR) imaging contrast agent gadolinium-ethoxybenzyl (EOB)-diethylene-triamine-pentaacetic acid (DTPA) in cholestasis. MATERIALS AND METHODS: Rat models of selective biliary obstruction (SBO) (n = 20) and total biliary obstruction (TBO) (n = 14) were used. Serial Gd-EOB-DTPA-enhanced MR images were obtained, and the findings were correlated with serologic, microcholangiographic, and histologic findings. RESULTS: In SBO rats, statistically significantly prolonged enhancement of ligated lobes occurred during the acute phase (P < .01) but was absent during the chronic phase owing to bile collateral vessels. In TBO rats, statistically significantly lower liver enhancement (P < .01) was observed as long as the obstruction persisted, until collateral bile ducts developed. CONCLUSION: The distinction between obstructed and unobstructed liver on Gd-EOB-DTPA-enhanced MR images suggests a novel application for visualizing cholestasis.

Animals↗
PubMed1994

Alcohol, other drugs, and criminality: a structural analysis.

The authors examine a model which specifies the relationships among criminality and the use of alcohol and other drugs. A pattern is hypothesized: The initiation of alcohol/drug use tends to progress from legal to illicit drugs; the early initiation of drugs increases the current use of drugs; and criminality is affected by the initiation/use patterns. Analyses based on data collected from individuals in jails, drinking driver programs, alcoholism treatment centers, and on probation indicate that the early onset of legal drug use induces the onset of illicit drug use. Criminality is affected by the current use of alcohol and cocaine. Comparison and contrast of findings from the four groups are provided.

Adult↗
PubMed1994

[The clinical role of appendectomy in surgical procedures for ovarian cancer].

To assess the clinical role of appendectomy in the surgical procedures for ovarian cancer. We have evaluated retrospectively 96 cases of epithelial ovarian cancer treated from Aug. 1986 to Aug. 1993. In 19 cases the appendiceal involvement was pathologically confirmed (19.8%). All of the patients with appendiceal metastases were found in stages III-IV, with an incidence of 33.3%. There was no significant statistical difference between either the histologic type of ovarian cancer or the side (left or right) of the ovarian involvement and the incidence of metastasis in the appendix. We conclude, with these results, that the appendix was not a primary site involved in the early stages. Appendectomy is not to be regarded as a routine surgical procedures in the early I-II stages of ovarian cancer, but it may help to reduce residual disease in advanced patients.

Adenocarcinoma, Mucinous↗
PubMed1994

[Effect of kidney tonifying herbs on morphological changes of adrenal cortex in androgen-sterilized rats].

Young rats of 9-day old with testosterone propionate subcutaneously injected were used as an androgen sterilized rats (ASR) model. On 80th day, herbal extract of tonifying the Kidney was fed for 14 days, all animals were sacrificed by cardiac perfusion method on 100 days of ages. Morphological studies with light and electron microscope, immunohistochemical studies with argyrophilic nucleolar organiser region (AgNOR) and proliferating cell nucleolar antigen (PCNA) were used for observations on the morphological change of adrenal cortex. In control group (treated with testosterone propionate only) the reticular zone of the adrenal cortex extented widely in which cellular fatty drops, AgNOR and PCNA increased apparently. In animal treated with herbs, the width of the reticular zone, the numbers of AgNOR and PCNA reduced significantly to normal levels (P < 0.01, P < 0.01, P < 0.01) and numbers of fatty drops also decreased. It suggests that during inducing ovulation in ASR tonifying Kidney herbs simultaneously regulated the adrenal function besides the chief function on pituitary-ovary regulation.

Adrenal Cortex↗
PubMed1994

[Treatment of the squamous carcinoma of the middle ear].

This essay is based on the analysis of clinical data coming from 20 cases of squamous carcinoma of the middle ear and review of lectures on squamous carcinoma of the middle ear. It shows that no clinical factor has been formed which would affect the prognosis of squamous carcinoma of the middle ear except the involved lymph node around the primary focus. Because the radical scalpel would destroy the local anatomic structure and it is difficult to drawn the tumor tissue perfectly. The author suggest that radiotherapy is the first choice of the simple squamous carcinoma of the middle ear. The surgical and radiation after surgery is not suitable preventive clearance and radiation is not necessary for the patient whose lymph node is negative.

Adult↗
PubMed1994

Determination of L-glutamate using flow injection analysis with immobilized L-glutamate oxidase reactor.

L-Glutamate oxidase (GOD) and horseradish peroxidase (HRP) were covalently coupled on alkylamine pretreated controlled pore glass (CPG) by means of glutaraldehyde. The immobilized enzymes were packed into a teflon tube and used in flow injection analysis (FIA) system for L-glutamate determination. A good linearity range was obtained at 0.1-2.0 mM, and the coefficient of variation was 0.7% (n = 8). More than 80 samples were measured within an hour. The stability of the immobilized GOD reactor was good, retaining 50% of its initial activity after 4 months storage in buffer at 4 degrees C. When the concentration of L-glutamate remained lower than 2.5 mM, the determination of L-glutamate in this system was not affected by pH and temperature within the range of 6.0-8.0 and 20-35 degrees C, respectively. The system was applied to determine L-glutamate in broth samples during L-glutamate fermentation and good correlations were achieved between results obtained with the FIA system, L-glutamate oxidase kit and Warburg's method.

Amino Acid Oxidoreductases↗
PubMed1994

The glutamate biosensor and its application to flow injection analysis system.

A micro-enzyme electrode was fabricated by cross-linking L-glutamate oxidase with glutaraldehyde on aminopropyl-platinized platinum wire. A flow injection analysis system with glutamate sensor was used for L-glutamate determination. The peak current is linearly related to the L-glutamate concentration in the range of 0.02-2.0 mM, with good performance, accuracy (CV = 0.4%), fast response (< 60s), and stability (> 20 days). The system was applied to determine the concentration of L-glutamate in a fermentation broth. The recovery rate was in the range of 98.7-107.5%.

Amino Acid Oxidoreductases↗
PubMed1994

Determination of oxygen permeability and volumetric oxygen transfer rate of shaken flasks.

The oxygen permeability passing through the gauze layer and the actual and apparent volumetric oxygen transfer rate, KLa and (KLa)app, respectively, were determined in specially designed Erlenmeyer flasks, which have an oxygen electrode inserted in the middle part of flasks. The oxygen transfer rate was determined by sulfite oxidation. As a result, the oxygen permeability passing through 8 layers of gauze at 37 degrees C, 220 rpm, with 50 ml sulfite solution in a 500-ml flask was 43.7 mol/m.h atm; as the oxygen partial pressure decreased by 6.1%, the value of KLa increased by 100%; the relationship between rotational speed of shaker, n(rpm); volume of flask, V(ml); liquid content in flask, VL(ml); temperature of shaker, t(degrees C) and KLa, as well as (KLa)app (1/h) were: [formula: see text]

Chemical Engineering↗
PubMed1994

[The protection of gut mucosa with early enteral feeding in burned rabbits].

The mechanisms of the protection of gut mucosa with early enteral feeding in burns were investigated. A 25% TBSA burn rabbit model, in which a gastrostomy, and a blind segment of the jejunum were formed before the thermal injury. 39 rabbits were randomly divided into three groups: A. burn and feeding with the nutritional fluid within 30 minutes postburn through gastrostomy. B. same as A except feeding with cold water instead of nutritional fluid; and C. no burn and fed freely. The results showed that burn injury caused an increase in mucosal oxygen consumption, intestinal uric acid formation and MDA (malondialdehyde) production, and decrease in submucosal blood flow. However, these were significantly improved by early enteral feeding after burn injury. The changes in the mucosa of the jejunal blind segment were similar to that of the rest of jejunum. It indicated that the effect of enteral feeding might be a systemic as well as a local one. It is concluded that the early enteral feeding can maintain the mucosal function and structure of the gut, as evidenced by a decrease in the mucosal hypermetabolism, improvement in submucosal blood flow and reduction in gut injuries as a result of reperfusion.

Animals↗