Biomedical subjects

J Yu

Publications and source records attributed to J Yu.

At least 37 records · Page 2Linked to original sources

PubMed1995

Effect of Helicobacter mustelae infection on ferret gastric epithelial cell proliferation.

The effect of Helicobacter mustelae infection on gastric epithelial proliferation was studied in ferrets colonized with H.mustelae and specific pathogen-free (SPF) ferrets not infected with H.mustelae. Thirteen H. mustelae-infected ferrets between the ages of 13 and 32 months and 16 SPF ferrets between 6 and 18 months were analyzed. Bacterial cultures, urease tests and Warthin-Starry stains were used to identify H.mustelae. Tissues obtained from the antrum and the body regions of the stomach were assayed by proliferating cell nuclear antigen (PCNA) immunohistochemistry and measured using a computerized color image analysis system. PCNA-expressing gastric epithelia in the antrum and the body regions were significantly increased in the H.mustelae-infected ferrets versus the SPF ferrets (P < 0.001). PCNA positivity in the antrum regions of both the H.mustelae-infected ferrets and SPF ferrets was significantly higher than that of the body regions (P < 0.001). Comparison of the histopathology of infected ferrets indicated that PCNA positivity correlated with the histological severity of gastritis. This study suggests that cell proliferation in ferret gastric mucosa increases with H.mustelae infection and provides evidence that PCNA is a useful biomarker for studying the changes in cell kinetics in the ferret stomach. The data also further support the use of the H.mustelae-infected ferret as an animal model for studying the pathogenesis of Helicobacter pylori-induced gastric diseases of humans.

Animals↗

PubMed1995

Long-term supplementation of canthaxanthin does not inhibit gastric epithelial cell proliferation in Helicobacter mustelae-infected ferrets.

The effect of canthaxanthin (CX), a nonprovitamin A carotenoid, on gastric epithelial proliferation was studied in ferrets colonized with Helicobacter mustelae, which causes a chronic gastritis and an increased gastric epithelial cell proliferation. Seven spayed female ferrets were dosed by gavage with CX beadlets (50 mg/kg body wt, 5 d/wk) over 2 y, whereas seven control animals were given placebo beadlets. At the end of the 2-y-period, ferrets were killed, and gastric tissues were obtained from the antrum and body regions. A cell-proliferating biomarker, proliferating cell nuclear antigen (PCNA), was assayed by immunohistochemistry. The PCNA positivity was measured by a computer-based image analysis system. Serum concentrations of carotenoids, retinoids and tocopherols were analyzed by HPLC. Serum antioxidant status was measured by the oxygen radical absorbance capacity (ORAC) assay. The PCNA positivity in both antrum and body regions was not significantly different between CX-fed ferrets and controls. Serum CX concentrations were significantly higher in CX-fed ferrets vs. controls (P < 0.001), whereas levels of other carotenoids, retinoids and tocopherols were not significantly different. The ORAC values were not significant different between groups. This study does not suggest inhibitory effects of CX on gastric epithelial cell proliferation in H. mustelae infected ferrets.

Animals↗

PubMed1995

Comparative mapping of aflatoxin pathway gene clusters in Aspergillus parasiticus and Aspergillus flavus.

Aflatoxins are toxic and carcinogenic secondary metabolites produced by the fungi Aspergillus flavus and A. parasiticus. Aflatoxins are synthesized by condensation of acetate units; their synthesis is estimated to involve at least 16 different enzymes. In this study we have shown that at least nine genes involved in the aflatoxin biosynthetic pathway are located within a 60-kb DNA fragment. Four of these genes, nor-1, aflR, ver-1, and omtA (previously named omt-1), have been cloned in A. flavus and A. parasiticus. In addition, five other genes, pksA, uvm8, aad, ord-1, and ord-2 have been recently cloned in A. parasiticus. The pksA, aad, and uvm8 genes exhibit sequence homologies to polyketide synthase, aryl-alcohol dehydrogenase, and fatty acid synthase genes, respectively. The cDNA sequences of ord-1 and ord-2 genes, which may be involved in later steps of aflatoxin biosynthesis, have been determined; the ord-1 gene product exhibits homology to cytochrome P-450-type enzymes. By characterizing the overlapping regions of the DNA inserts in different cosmid and lambda DNA clones, we have determined the order of these aflatoxin pathway genes within this 60-kb DNA region to be pksA, nor-1, uvm8, aflR, aad, ver-1, ord-1, ord-2, and omtA in A. parasiticus and nor-1, aflR, ver-1, ord-1, ord-2, and omtA in A. flavus. The order is related to the order in enzymatic steps required for aflatoxin biosynthesis. The physical distances (in kilobase pairs) and the directions of transcription of these genes have been determined for both aflatoxigenic species.

Aflatoxins↗

PubMed1995

Increased expression of Aspergillus parasiticus aflR, encoding a sequence-specific DNA-binding protein, relieves nitrate inhibition of aflatoxin biosynthesis.

The aflR gene from Aspergillus parasiticus and Aspergillus flavus may be involved in the regulation of aflatoxin biosynthesis. The aflR gene product, AFLR, possesses a GAL4-type binuclear zinc finger DNA-binding domain. A transformant, SU1-N3 (pHSP), containing an additional copy of aflR, showed increased transcription of aflR and the aflatoxin pathway structural genes, nor-1, ver-1, and omt-1, when cells were grown in nitrate medium, which normally suppresses aflatoxin production. Electrophoretic mobility shift assays showed that the recombinant protein containing the DNA-binding domain, AFLR1, bound specifically to the palindromic sequence, TTAGGCCTAA, 120 bp upstream of the AFLR translation start site. Expression of aflR thus appears to be autoregulated. Increased expression of aflatoxin biosynthetic genes in the transformant might result from an elevated basal level of AFLR, allowing it to overcome nitrate inhibition and to bind to the aflR promotor region, thereby initiating aflatoxin biosynthesis. Results further suggest that aflR is involved in the regulation of multiple parts of the aflatoxin biosynthetic pathway.

Aflatoxins↗

PubMed1995

The cytochrome bc complex (menaquinone:cytochrome c reductase) in Bacillus subtilis has a nontraditional subunit organization.

We have identified an operon in Bacillus subtilis, designated qcr, that is thought to encode a quinone: cytochrome c reductase. Northern (RNA blot) analysis suggests a tricistronic operon. The operon is located at about 200 degrees on the B. subtilis map. Disruption of the operon leads to loss of a 22-kDa cytochrome c from membrane preparations. The structure of the putative protein products of the qcr operon suggests a protein complex that is closely related to but distinct from known cytochrome bc1 and b6f complexes, which catalyze electron transfer from a quinol to a c-type cytochrome or to plastocyanin. QcrA is similar to Rieske-type iron-sulfur proteins; QcrB is similar in size and sequence to b-type cytochromes from b6f complexes; and QcrC has a novel structure that resembles a fusion of a subunit IV (found in b6f complexes) to a cytochrome c. Transcription of the operon is induced at the end of exponential growth from a sigma A-like promoter. This transition state induction appears to be dependent on the downregulation of abrB expression, which is mediated by Spo0A activation. As bacteria move from the transition state into sporulation, transcription of the operon is reduced in a sigma F-dependent manner.

Amino Acid Sequence↗

PubMed1995

Glenoid labrum: MR imaging with histologic correlation.

PURPOSE: To document the histopathologic basis of altered intralabral and sublabral signal intensity on magnetic resonance (MR) images. MATERIALS AND METHODS: Ten fresh cadaveric shoulder specimens underwent transaxial MR imaging with T1-weighted, proton-density-weighted, and T2-weighted spin-echo; multiplanar gradient-recalled echo (MPGR); three-dimensional Fourier transform gradient-recalled echo (GRE); spoiled gradient-recalled echo (SPGR); and T1-weighted, fat-suppressed sequences before and after intraarticular injection of gadolinium. Shoulders were then frozen and transversely sectioned, and histologic analysis of the labrum was performed. RESULTS: Altered intralabral signal intensity correlated with fibrovascular tissue, mucoid or eosinophilic degeneration, calcification, ossification, synovial tissue, or combinations of these findings. A sublabral transitional band of intermediate signal intensity correlated with a transitional zone of fibrocartilage. CONCLUSION: There are several causes of altered intralabral signal intensity. A transitional fibrocartilaginous zone correlates with sublabral increased signal intensity. Intraarticular administration of gadolinium improves evaluation of the glenoid labrum.

Aged↗

PubMed1995

A region-specific microdissection library for human chromosome 2p23-->p21 and the analysis of an interstitial deletion of 2p21.

A region-specific library of human chromosome 2p23-->p21 was constructed using microdissection and microcloning techniques. Analysis of 94 single-copy microclones from the library showed that 64% were derived from the dissected region. Ten microclones were further mapped to the 2p21 region using a patient with an interstitial deletion of 2p21 and displaying holoprosencephaly, an abnormal embryonic development in midbrain and midface.

Animals↗

PubMed1995

Drunk-driving recidivism: predicting factors from arrest context and case disposition.

OBJECTIVE: Efforts were made to examine drinking-driving recidivism in relation to arrest context and subsequent case disposition. Three specific hypotheses were tested, regarding blood alcohol concentration, time of arrest and sanctions. METHOD: Complete 1989, 1990 and 1991 traffic ticket files from the New York State police were the baseline data for the study. RESULTS: Analyses show that high recidivism rates tend to be among offenders whose alcohol tickets were not disposed in a timely manner and offenders who were able to avoid a conviction even though their tickets were disposed. Other factors, such as time of arrest and the BAC reading at the arrest, do not significantly predict drinking-driving recidivism. CONCLUSIONS: Findings indicate that, after drinking-driving laws have been dramatically reinforced, an important remaining task is to swiftly and effectively convict drinking-driving offenders. In addition, a legal mechanism should be established to monitor multiple offenders and offenders who actively delay or manipulate court processing.

Accidents, Traffic↗

PubMed1995

Decreased production of endothelin-1 in asthmatic children after immunotherapy.

Endothelin-1 (ET-1) is an endothelium-derived peptide that may be the most potent vasoconstrictor and bronchoconstrictor yet known. To investigate the role of ET-1 in the pathogenesis of bronchial asthma and the effect of immunotherapy (IT) on endothelin production, we measured the in vivo and in vitro production of ET-1 in 24 asthmatic children before and after specific allergen IT for 2 years as well as in age-matched healthy controls. Our results showed that both the plasma concentrations and in vitro production of ET-1 from the supernatants of cultured mononuclear cells (MNCs) were significantly higher in asthmatic children than in control subjects. The mean plasma levels of ET-1 in asthmatic children before or after IT were significantly higher than in controls (49.4 +/- 26.5 and 30.6 +/- 20.7 ng/L vs. 13.2 +/- 8.5 ng/L, p < 0.05 and p < 0.01, respectively). When stimulated with phytohemagglutin (PHA) (1 microgram/ml) or mite extract (10 micrograms/ml) for 3 days, mononuclear cell from asthmatic children before IT produced significantly higher ET-1 than did those after IT (31.8 +/- 23.0 vs. 18.0 +/- 15.7 ng/L, stimulated with mite, and 67.9 +/- 22.4 vs. 25.0 +/- 13.3 ng/L, stimulated with PHA). The decreased production of ET-1 in MNCs culture supernatant of asthmatic children after IT indicated that immunotherapy may result in an immune nonresponsive state, which may reverse the abnormal secretory pattern of ET-1 production in asthmatic children and partly account for its clinical effectiveness in treating atopic patients.

Allergens↗

PubMed1995

Alcohol purchase age laws and the serial beginning drinker in New York.

Raising the drinking age twice in New York State in the 1980s might have created a generation of "serial beginning drinkers." Findings indicate that when young adults become beginning drinkers, their chances of drinking-driving increase; when they become serial beginning drinkers, their involvement in drinking-driving remains high over time. The beginning drinkers belong to a special historical period and are only composed of birth cohorts of 3 or 4 years (mainly early 1960s). The effect of the serial beginning drinker should fade out as those birth cohorts grow into maturity.

Adolescent↗

PubMed1995

Construction and expression of 75kDa readthrough protein gene from beet necrotic yellow vein virus.

Using DNA recombinant techniques, coat protein (CP) gene and 54kDa fragment from beet necrotic yellow vein virus (BNYVV) RNA2 were ligated to construct 75kDa readthrough protein gene. Comparing with wild-type 75kDa readthrough protein gene, four nucleotides of the constructed gene were replaced, including CP amber termination codon UAG to AUG. Correspondingly, two amino acids were changed. The temperature inducible expression vectors containing 75kDa readthrough protein gene or its 54kDa fragment were constructed and transformed into E. coli BL21 (DE3), respectively. The results of SDS-PAGE and Western blotting showed that (1) the 75kDa readthrough protein gene was expressed specifically by temperature induction and some smaller protein components, one of which is 37 kDa, were observed as well; (2) only a 37kDa protein was produced from the 54kDa fragment.

Base Sequence↗

PubMed1995

[Histopathologic study on the anterosuperior spreading of supraglottic carcinoma].

Pathologic characteristic of supraglottic carcinoma spreading anterosuperiorly in 100 cases was investigated by whole-organ sections of the larynx. The results showed that 75% of supraglottic carcinomas were found to spread anterosuperiorly. In these cases, carcinoma in the epiglottis-ventricular fold accounted for 90%; epiglottic carcinoma 81.8%; and carcinoma in the ventricular fold 33.3%. Carcinoma in the aryepiglottic fold and arytenoid region was not noted to spread anterosuperiorly. In the cases with anterosuperior spreading of supraglottic carcinoma, the pre-epiglottic space was most commonly involved, which accounted for 60% of the cases; while the lingual surface of the epiglottis 42%; the vallecula 17%; the base of the tongue 12%; and the anterosuperior part of the thyroid cartilage 7%.

Adult↗

PubMed1995

[Treatment of breast cancer with ipsilateral supraclavicular node metastases].

During 1954-1977, among 2803 cases of breast cancer 99 (3.5%) had ipsilateral supraclavicular node mestastases. The results of treatment are reported, based on follow-up for more than 10 years. According to the treatment modality, the patients were divided into 4 groups: I. surgery with postoperative adjuvant chemotherapy and radiation therapy; II. radiation and chemotherapy; III. chemotherapy; IV. no treatment. In group I, surgical procedures consisted of segmental mastectomy in 6; simple mastectomy in 7; modified radical mastectomy in 16; standard radical mastectomy in 12, and extended radical mastectomy in 3. The over-all five-year survival rate was 9%. It was 18% (8/44) in group I, but only 5% (1/21) in group II. None survived for 5 years in group III and group IV. The results seem to indicate that more aggressive multi-modality treatment of breast cancer with ipsilateral supraclavicular lymph node metastases is indicated to expect better survival.

Adult↗

PubMed1995

Vitamin D analogs: new therapeutic agents for the treatment of squamous cancer and its associated hypercalcemia.

We have examined the in vitro effects of 1,25 dihydroxy-vitamin D3 [1,25(OH)2D3] and of two side-chain modified analogs of 1,25(OH)2D3 (EB1089 and MC903) on cell growth and parathyroid hormone related peptide (PTHRP) production in immortalized (HPK1A) and neoplastic (HPK1A-ras) keratinocytes. Cell proliferation was strongly inhibited by 1,25(OH)2D3 and its analogs in HPK1A cells, and in this system EB1089 was 10-100 times more potent than 1,25(OH)2D3 or MC903. A similar effect on cell proliferation was observed in HPK1A-ras cells; however, 10-fold higher concentrations of 1,25(OH)2D3 or its analogs were required. We also observed a strong and dose-dependent inhibitory effect of these compounds on PTHRP secretion and gene expression. In both immortalized and neoplastic keratinocytes, EB1089 was 10-100 times more potent than 1,25(OH)2D3 or MC903 on inhibiting PTHRP production. However, although effective in HPK1A-ras cells, 10-fold higher concentrations of 1,25(OH)2D3 or its analogs were required to produce similar actions in this neoplastic model. These studies therefore demonstrate that a 1,25(OH)2D3 analog with low calcemic potency in vivo (EB1089) can inhibit keratinocyte proliferation and PTHRP production by such cells with greater potency than 1,25(OH)2D3. The observed effects of such analogs in neoplastic keratinocytes predicts their potential usefulness in vivo in inhibiting squamous cancer growth and its associated hypercalcemia.

Animals↗

PubMed1995

[Predictors of hepatic functional reserve in cirrhotic patients].

We have determined the interstitial ratio, hepatocyte numerical density on area (NA) by the method of Luzex-F Image Analyser, and the level of serum prealbumin (PA), choline esterase activity (ChE) by agarose immunodiffusion and ratemetry in control group (14 cases) and 25 cirrhotic patients undergoing pericardial devascularization. The results were compared with traditional hepatic function grade (Child's Grade). We found that NA, PA, and ChE are independently useful in evaluating the hepatic functional reserve in cirrhotic patients.

Adult↗

PubMed1994

Clinical significance of p53 mutations in relapsed T-cell acute lymphoblastic leukemia.

In T-cell acute lymphoblastic leukemia (T-ALL), p53 gene mutations were found in 12 of 51 patients in first relapse (24%). In a retrospective study, bone marrow samples at diagnosis were obtained from 9 of the 12 relapsed patients with p53 mutation; only one patient was found to harbor a p53 mutation at diagnosis. No further p53 mutations were identified in 18 unpaired diagnosis T-ALL samples. This is the first report of a p53 mutation in T-ALL at diagnosis. p53 mutations in relapsed T-ALL were clinically relevant. Patients with p53 mutations experience a shorter duration of survival than those patients without p53 mutations. Additionally, patients with p53 mutations were significantly less likely to have achieved a complete second remission from reinduction therapy than those patients without p53 mutations and experience a shorter duration of survival from relapse even when a second reinduction is obtained. Though primarily identified only at relapse, p53 mutations were also associated with a decreased duration of first remission and overall decrease in survival from diagnosis. Patients with p53 mutations had a 3.8-fold increase in risk of death than those patients without p53 mutations. These findings suggest that p53 mutation is associated with poor clinical outcome that is characterized by (1) a shortened duration of survival after first relapse; (2) a reduced response to reinduction therapy; (3) a shortened duration of first remission; and, hence, (4) an overall decreased duration of survival and increased risk of death.

Base Sequence↗

PubMed1994

Ankyrin and beta-spectrin accumulate independently of alpha-spectrin in Drosophila.

We report the identification and initial characterization of Drosophila melanogaster ankyrin. Oligonucleotide primers based on the spectrin-binding domain of human brain ankyrin were used to amplify Drosophila genomic DNA. A cloned 184-bp PCR product was used to isolate Drosophila ankyrin cDNAs. Ankyrin cDNA probes detected a 5.5-kb transcript from embryonic poly(A)+ RNA and a single polytene chromosome locus (101F-102A). The cDNA sequence encodes a 170-kDa protein that is 53% identical to human brain ankyrin (Ank2). Antibodies directed against a recombinant fragment of Drosophila ankyrin reacted with a 170-kDa polypeptide from Drosophila embryos, larvae, S2 cells, and adult flies. The ankyrin antibody coimmunoprecipitated alpha- and beta-spectrin with ankyrin in detergent extracts of Drosophila embryo membranes. Antibodies against Drosophila ankyrin, alpha-spectrin and beta-spectrin were used to detect these proteins in wild-type and alpha-spectrin-mutant larvae. alpha-Spectrin levels were greatly diminished in mutant larvae, but levels of ankyrin and beta-spectrin were indistinguishable from wild type. The persistence of ankyrin and beta-spectrin may explain the relatively mild phenotype of alpha-spectrin mutants during early Drosophila development.

Amino Acid Sequence↗

PubMed1994

Solid-phase derivatization reactions for biomedical liquid chromatography.

Polymeric reagents have been developed for performing off- and on-line derivatizations of numerous organic analytes in HPLC-detection modes. Such reagents utilize ionic or covalent attachment of labile tags that possess specific detector enhancement properties: ultraviolet, electrochemical, fluorescence, and so forth. Specific synthetic procedures have evolved to generate various linkages of the tag to the underlying, polymeric support, usually involving activated ester connections (leashes). The polymer itself may play a number of roles in the nature of the overall reactions, such as hydrophobic-hydrophillic exclusion, pore size restriction, stabilization of the attachment leashes, and protection of the tags from hydrolysis in aqueous media. The basic, underlying chemistry of polymeric reagents has evolved to the point where it is possible to engineer the polymer support itself, the attachment leash, and the various tags that are then transferred to the analyte molecules. These procedures have now reached the stage of commercialization and practical applicability for real-world drugs and bioorganics in complex biofluid type samples. Polymer supported reagents can now be used for direct injection of biofluids with solid-phase (hydrophobic) extraction of the analytes of interest, followed by sample cleanup, derivatization, elution onto the HPLC column, peak compression, gradient HPLC elution, multiple detection, and final data interpretation with quantitation. This review summarizes much or most of what has been described in the scientific literature over the past decade in the various areas where polymeric reagents are being used for derivatization in HPLC and in capillary electrophoresis as well.

Chemistry Techniques, Analytical↗