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Biomedical subjects

J Yu

Publications and source records attributed to J Yu.

At least 667 records · Page 37Linked to original sources
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↗
PubMed1995

High expression of synthetic human interferon-gamma cDNA in E. coli.

Human interferon-gamma (IFN-gamma) cDNA was synthesized, and it makes the usage of favorable codons in E. coli. The authors got 9 different expression plasmids which contain the synthetic IFN-gamma-cDNA and have different spaces between SD sequence and ATG. The free energies G0f298 in the formation of stable secondary structure in the translation initiation region (TIR) are different in various expression plasmids. One of them, pLY4-gamma 5, can highly yield INF-gamma which will be about 60%-80% of the total bacterial proteins, such a high expression was hardly noted in literature. The reasons of high expression in this work are optimal spaces between SD and ATC, favorable delta G0f298, favourable condons usage for E. coli.

Amino Acid Sequence↗
PubMed1995

cDNA cloning and sequencing of 54kDa fragment of the 75kDa readthrough protein gene from beet necrotic yellow vein virus.

With viral RNA extracted from purified beet necrotic yellow vein virus (BNYVV) isolated from Inner Mongolia, the first strand of cDNA encoding a 54kDa fragment of the 75kDa readthrough protein on the RNA2 was synthesized by reverse transcription. A double-strand cDNA fragment of 1.5 kb was obtained after 30 cycles of PCR amplification. The fragment was ligated into and mapped on pGEM-7Zf(+). The result of sequence analysis shows that the 54kDa readthrough domain is 1509 nucleotides (nt). Compared with F13 isolate, the fragment shares 94.97% identity in terms of nucleotides with 3 nt deletion and 96.42% identity of deduced amino acids.

Amino Acid Sequence↗
PubMed1995

[Percutaneous absorption of venenum bufonis in vitro].

V-C horizontal diffusion cell and HPLC determination have been used to study the effect of 1,2-propanediol and azone on the percutaneous absorption Venenum Bufonis. The contents of resibufogenin have been determined through mouse skin in vitro by HPLC. The results indicate that the contents get increased when 1,2-propanediol is added and that azone can shorten the lag time of percutaneous absorption of resibufogenin through mouse skin in vitro.

Amphibian Venoms↗
PubMed1995

[Multiple analysis for the c-Ha-ras activation and DNA content in human gastric precancerous lesions].

The relationship between ras activation and over expression of p21 protein and DNA content in progression from benign to malignant of gastric mucosa was studied. The point mutation at 12 of c-Ha-ras oncogene was detected with PCR and specific oligonucleotide probe hybridization, the expression of ras p21 and DNA ploidy by flow cytometry was also carried out simultaneously on 66 human gastric tissues with gastric cancer and precancerous lesions, some of the patients were followed up for 42 to 60 months. The results showed that: activation of ras oncogene and p21 overexpression may be involved in the early stages of gastric cancer; DNA aneuploidy may not help for the early diagnosis, but can be useful for the diagnosis of gastric cancer in pathology; gastric cancer with mutational activation at 12 of c-Ha-ras may has unfavourable future. It concluded that c-Ha-ras activation and p21 overexpression may be help to early diagnosis of gastric cancer in clinic.

Aneuploidy↗