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Biomedical subjects

J Yu

Publications and source records attributed to J Yu.

At least 487 records · Page 27Linked to original sources
PubMed1998

Perceived parental/peer attitudes and alcohol-related behaviors: an analysis of the impact of the drinking age law.

This study examined the perceived change in parental and peer attitudes toward underage drinking associated with the raising of the legal drinking age and its effect on youthful alcohol use and drinking driving. The analysis was based on the New York State Youth Alcohol Survey, a series of four surveys conducted in 1982, before the enactment of the 19 drinking age law; 1983, after the enactment of the 19 drinking age law, 1985, before the 21 drinking law; and 1986, after the 21 drinking age law. Findings indicate that the effect of perceived parental attitudes is specific to underage alcohol use, but the effect of perceived peer attitudes is general to both underage and legal drinkers. Results from this study suggest that parental supervision is a key factor in enforcing the drinking age law and reducing youthful alcohol use. Parents' participation should be included in all enforcement and prevention/intervention efforts.

Adolescent↗
PubMed1998

YUA001, a novel aldose reductase inhibitor isolated from alkalophilic Corynebacterium sp. YUA25. I. Taxonomy, fermentation, isolation and characterization.

YUA001 is a novel aldose reductase inhibitor produced from alkalophilic Corynebacterium sp. YUA25 isolated from soil. YUA001 was purified from the supernatant of culture broth by successive silica gel column chromatography, Sephadex LH20-100 gel column chromatography, and HPLC. From instrumental analysis, molecular formula of YUA001 is C13H19NO2 and its molecular weight is 221. It exhibits potent aldose reductase inhibition activity and has no antimicrobial activity against some gram-positive or gram-negative bacteria, fungi and yeast.

Aldehyde Reductase↗
PubMed1998

[Anatomical and clinical studies on the free posterior leg flap pedicled with the lateral popliteal cutaneous artery].

OBJECTIVE: To investigate the feasibility of free transference of the posterior leg flap which is supplied by the lateral popliteal cutaneous artery. METHODS: Anatomical dissection is performed in twenty-two freshly amputated adult lower extremities. RESULTS: The discovery rate of the lateral popliteal cutaneous artery is 100%. The vessel is 20.0 +/- 5.7 cm in length with an exterior diameter of 1.28 +/- 0.25 mm at the junction of the popliteal artery. The course of the artery is constant, and it is usually accompanied by the lateral sural cutaneous nerve. Seven operations using this free flap have been performed successfully. CONCLUSION: The flap is suitable for repairing medium-sized soft tissue defects or for functional reconstruction.

Adolescent↗
PubMed1998

[Significance of pathological type in cervical lymph metastasis of laryngeal cancer].

To research significance of pathological type in cervical lymph metastasis of laryngeal cancer. Observing metastasis lymph nodes in serial sections of 55 cases neck dissection specimens with microscope. Single type 21 cases, 90% of them were occult metastasis, three-year survival rate was 90%. Multiple types 10 cases, 70% of them were occult metastasis, three-year survival rate was 70%. Gathering type 24 cases, 92% of them can be palpated by physician, three-year survival rate was 54%. It is suitable that cervical metastasis lymph nodes of laryngeal cancer were divided into three types in pathology. It is significance for treatment and prognosis.

Adult↗
PubMed1998

[Alanyl-glutamine dipeptides protected the liver function by increasing the hepatic glutathione].

OBJECTIVE: Glutathione (GSH) is a major antioxidant which protects hepatic tissues from free radical injury. Alanyl-Glutamine (ALA-GLN) proved to be a precursor of GSH synthesis, was used to investigate the relationship to GSH biosynthesis which may be effective for hepatic protection. METHODS: 20 male Wistar rats were randomly divided into two groups receiving standard parenteral nutrition (STD) supplemented with or without ALA-GLN for 7 days. At 5th day 5-fluorouracil (5-FU) was injected peritoneally, the blood samples for GSH, GSSG, ALT (sGPT), AKP and TBilli tests were measured after 4-8 h. RESULTS: The concentration measurements were significantly different in ALA-GLN group compared with STD animals in serum GLN (687.3 +/- 49.8) vs (504.9 +/- 38.6) mumol/L, P < 0.05), serum GSH (14.37 +/- 5.16) vs (7.08 +/- 3.16) mumol/L, P < 0.01) and in liver GSH content (6.86 +/- 2.46) vs (4.38 +/- 1.63) mumol/g liver tissue, P < 0.05). Rats in ALA-GLN group have lesser elevations in hepatic enzymes after 5-FU administration. CONCLUSIONS: The supplemented nutrition ALA-GLN protected the liver function through increasing the glutathione biosynthesis and preserving the glutathione stores of hepatic tissue.

Animals↗
PubMed1998

[Determination of formaldehyde in indoor air by gas chromatography].

Formaldehyde in indoor air was collected by water, derivatized with 2,4-dinitrophenylhydrazine and extracted by cyclohexane. The sample was separated on an OV-17 and QF-1 mixed chromatographic column and determined by electron capture detector. The detection limit was 0.02 mg/L (solution), the minimum detectable concentration was 0.01 mg/m3 while 10 L indoor air was collected. The results show that this is a rapid and sensitive method with less interferences and fairly good precision. The recoveries were 71.0%-90.4% and coefficients of variation were 4.1%-6.5%. The development of this method has made a reliable methodological foundation for the determination of formaldehyde in indoor air.

Air Pollutants↗
PubMed1998

[Immune modulatory and therapeutic effect of lentinan on condyloma acuminatum].

OBJECTIVE: To observe the immune modulatory and therapeutic effect of lentinan on condyloma acuminatum (CA). METHODS: Thirty-six CA patients were randomly divided into two groups, 19 in the test group treated with lentinan plus CO2 laser irradiation and 17 in the control group treated with laser irradiation alone. Their T-lymphocyte subsets of peripheral blood and level of serum interleukin-2 (IL-2) and soluable interleukin-2 receptor (SIL-2R) were determined before and after treatment, and the recurrence rates of the two groups were compared. RESULTS: After treatment, in the test group, the CD4/CD8 ratio, serum IL-2 raised and serum SIL-2R lowered significantly (P < 0.05, 0.05, 0.05 respectively) as compared with before treatment, while those parameters were not changed significantly in the control group. The recurrence rate of the test group was lower than that of the control group, P < 0.05. CONCLUSION: Lentinan could modulate the cellular immunofunction of CA patients and reduce the recurrence rate of CA.

Adjuvants, Immunologic↗
PubMed1998

[Radionuclide pulmonary perfusion imaging in evaluating pulmonary hypertension in patients with congenital heart disease].

OBJECTIVE: To evaluate the degree of pulmonary hypertension in patients with congenital heart disease (CHD) by using radionuclide pulmonary perfusion imaging. METHOD: The pulmonary perfusion in 81 patients with left to right cardiac shunts was examined by scintigram with macroaggregates of (99m)Tc-labeled human serum albumin (PPS). PPS was analyzed for (1) lung regional radionuclide count (LRC), (2) right upper and lower lung count ratio (RULR), (3) kidney count ratio (KCR). The results were compared with those of cardiac catheterization exam. RESULT: There were correlation between mean pulmonary arterial pressure (mPAP), total pulmonary resistance (TPR), and PPS (KCR, RULR with mPAP gamma = 0.25, 0.35; LRC, KCR with TPR gamma = -0.34, 0.29). Five patients repeated PPS test after early operation. There were no changes in PPS. CONCLUSION: The degree of reversibility of pulmonary hypertension in patients with CHD could be quantitatively analysed by PPS.

Adolescent↗
PubMed1998

[Study on the analytical method of s-triazine herbicide residues in soil and maize].

The sample was extracted with a mixture of V(acetonitrile): V(methanol) = 1:1. After filtration, the extract was defatted with petroleum ether and then it was passed through a short C18 column for pretreatment and analysed by Nova-Pak C18 column, 150 mm x 3.9 mm i.d., with V(MeOH): V(H2O) = 55:45 as mobile phase. The recoveries were 82.4%-99.8% for cyanazine, 85.6%-102.3% for atrazine and 89.1%-108.4% for simetryne.

Atrazine↗
PubMed1998

[Studies on the chemical constituents of the leaves from Artabotrys hexapetalus].

Artabotrys hexapetalus (annonaceae) is distributed in southern China. As a Chinese folk herb medicine, its root and fruits are used to treat malaria and scrofula, respectively. Two new flavonol glycosides, artabotryside-A (1), -B (2), three known flavonoids: taxifolin (3), 7-O-glucoluteolin (4), apigenin-7-O-apiosyl(1-->2) glycoside (5), and two organic acid: succinic (6) and fumaric acid (7) have been isolated from the leaves of A. hexapetalus. The structures of 1 and 2 were elucidated as quercetin-3-O-alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinofuranoside (1) and kaempferol-3-O-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinofuranoside (2), respectively, on the basis of spectral analysis. The compounds 3 through 7 were found from A. hexapetalus for the first time.

Annonaceae↗
PubMed1998

[Fluorescence emission spectra of petroleumsulfonate and OP-10 in multi-components aqueous solutions].

The determination of surfactant(s) in the alkaline/surfactant/polymer flooding solutions was an uneasy job. For this purpose, the method of fluorescence emission by phenoxy-containing surfactants in dilute solutions is suggested. The fluorescence emission intensity changes linearly with in the extent of low surfactant concentrations below the critical micelle concentration (CMC) and is not influenced by the presence of alkali, polymer PHPAM and salts. Under certain conditions the fluorescence emission by petroleum sulfonate and OP-10 in a multi-components aqueous solution can be detected independently. This method is high-selective, sensitive (the lowest detectable concentration 10(-7) mol/L) and microanalytical (the amount of test solution 2-3 microL).

English Abstract↗
PubMed1998

mRNA stabilization by the ompA 5' untranslated region: two protective elements hinder distinct pathways for mRNA degradation.

The 5' untranslated region (UTR) of the long-lived Escherichia coli ompA transcript functions as an mRNA stabilizer that can prolong the cytoplasmic lifetimes of a variety of messages to which it is fused. Previous studies have identified two domains of this 5' UTR that together are responsible for its stabilizing effect. One is a 5'-terminal stem-loop. The other is a single-stranded RNA segment (ss2) that contains a ribosome binding site highly complementary to 16S ribosomal RNA. Here we report a detailed investigation of the function of these two stabilizing elements. Our data indicate that mRNA protection by a 5' stem-loop requires no sequence features or thermodynamic stability beyond the minimum necessary for stem-loop formation. Stabilization by ss2 appears to result not from a high frequency of translation initiation, but rather from a high degree of occupancy of this 5' UTR segment by bound ribosomes. Although close spacing of translating ribosomes is not critical for message stabilization by the ompA 5' UTR, mRNA longevity does require the periodic passage of ribosomes through the protein-coding region. Unlike bound ribosomes, which hinder mRNA cleavage by RNase E, the 5' stem-loop appears to impede degradation of ompA mRNA via a distinct pathway that is RNase E-independent. These findings imply that the ompA 5' UTR prolongs mRNA longevity by impeding multiple pathways for mRNA degradation.

Bacterial Outer Membrane Proteins↗
PubMed1997

Functional expression cloning and characterization of SFT, a stimulator of Fe transport.

A stimulator of Fe transport (SFT) was identified by functional expression cloning in Xenopus oocytes. SFT-mediated transport has properties defined for transferrin-independent Fe uptake, but its cytolocalization in recycling endosomes and the observed stimulation of transferrin-bound Fe assimilation indicate a key role in intracellular Fe membrane transport as well. SFT has six predicted transmembranous domains and a functionally important RExxE motif that resembles domains involved in yeast Fe transport and Fe-binding by ferritin L-chains. The observation that SFT oligomerizes, along with other structural and mechanistic features, suggests it may be a member of either the ATP-binding cassette or cation diffusion facilitator families. The 3' untranslated region of SFT contains a translation inhibitory element and inhibition of SFT expression in Xenopus oocytes was found to be relieved by coinjection of transcripts from other defined cDNAs that are also described in this report. SFT is the first component of the mammalian Fe membrane transport machinery to be identified.

Amino Acid Sequence↗
PubMed1997

The affected gene underlying the class K glycosylphosphatidylinositol (GPI) surface protein defect codes for the GPI transamidase.

The final step in glycosylphosphatidylinositol (GPI) anchoring of cell surface proteins consists of a transamidation reaction in which preassembled GPI donors are substituted for C-terminal signal sequences in nascent polypeptides. In previous studies we described a human K562 cell mutant, termed class K, that accumulates fully assembled GPI units but is unable to transfer them to N-terminally processed proproteins. In further work we showed that, unlike wild-type microsomes, microsomes from these cells are unable to support C-terminal interaction of proproteins with the small nucleophiles hydrazine or hydroxylamine, and that the cells thus are defective in transamidation. In this study, using a modified recombinant vaccinia transient transfection system in conjunction with a composite cDNA prepared by 5' extension of an existing GenBank sequence, we found that the genetic element affected in these cells corresponds to the human homolog of yGPI8, a gene affected in a yeast mutant strain exhibiting similar accumulation of GPI donors without transfer. hGPI8 gives rise to mRNAs of 1.6 and 1.9 kb, both encoding a protein of 395 amino acids that varies in cells with their ability to couple GPIs to proteins. The gene spans approximately 25 kb of DNA on chromosome 1. Reconstitution of class K cells with hGPI8 abolishes their accumulation of GPI precursors and restores C-terminal processing of GPI-anchored proteins. Also, hGPI8 restores the ability of microsomes from the mutant cells to yield an active carbonyl in the presence of a proprotein which is considered to be an intermediate in catalysis by a transamidase.

Acyltransferases↗
PubMed1997

Mapping the regions of the complement inhibitor CD59 responsible for its species selective activity.

CD59 is a widely distributed membrane-bound glycoprotein that inhibits the formation of the cytolytic membrane attack complex (MAC) of complement on host cells. CD59 from different species varies in its capacity to inhibit heterologous complement, and this species selective function of CD59 contributes to the phenomenon of homologous restriction. Here, we demonstrate that human CD59 is not an effective inhibitor of rat complement, although rat CD59 inhibits rat and human complement equally well. By constructing human-rat CD59 chimeric proteins, we have mapped the residues important in conferring human CD59 species selectivity to two regions; 40-47 and 47-66 in the primary structure. Analysis of a model of the molecular surface of human CD59 revealed that residues 40-66 mapped to a region in the three-dimensional structure that surrounds residues previously identified as important for CD59 function.

Amino Acid Sequence↗
PubMed1997

Ex vivo experiment on radiofrequency liver ablation with saline infusion through a screw-tip cannulated electrode.

PURPOSE: To investigate whether radiofrequency (RF) therapy with hypertonic saline infusion through a hollow screw-tip electrode can cause a lesion size suitable for liver tumor ablation. MATERIALS AND METHODS: RF tissue ablation of 180 sites was performed by using a hollow screw-tip electrode in 40 freshly excised swine livers. Under both power and temperature control modes, the ablation effects with and without various regimes of 5% hypertonic saline (1 ml/min) prior to and/or during the procedure were compared by measuring the size of lesions at dissection and confirmed by T1 and T2 weighted magnetic resonance (MR) imaging. RESULTS: The maximal lesion diameter of 5.5 cm was reached at 30 W with saline infusion 1 min prior to and during 12 min of ablation. The smaller sizes (P < 0.01) between 0.3 and 2.5 cm in diameter were met with noninfusion or preinfusion-only groups. The RF ablation lesions appeared as hyper- and hypointense areas on T1 and T2 MR images, respectively. CONCLUSIONS: RF ablation in combination with present hollow screw-tip electrode and saline infusion allows for necrotic development of suitable size for liver tumor ablation. Such ablated lesions can be visualized with MR imaging.

Animals↗